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    Tytuł:
    Doctor Honoris Causa of the Adam Mickiewicz University for Professor Brian C. J. Moore
    Doktor Honoris Causa Uniwersytetu Adama Mickiewicza dla prof. Briana C. J. Moore’a
    Autorzy:
    Sęk, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/177129.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Brian Cecil Joseph Moore
    Opis:
    On November 9th, a.d. 2015, Professor Brian Cecil Joseph Moore from Cambridge University (UK), received the title of Doctor Honoris Causa of Adam Mickiewicz University from the hands of His Magnificence, the Rector of the AMU. Professor Brian Moore is a great scholar with a broad, in-depth knowledge and extremely wide research interests in many areas that go far beyond the mainstream of his research. He is a physicist, an acoustician and a psychologist.
    Źródło:
    Archives of Acoustics; 2016, 41, 2; 351-354
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Frequency Discrimination for Amplitude Modulated Sinusoidal Signals at High Carrier Frequencies
    Autorzy:
    Sęk, A.
    Kordus, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1359956.pdf
    Data publikacji:
    2014-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    43.66.Fe
    43.66.Hg
    Opis:
    The current study is a continuation of experiments presented by Sęk and Bukała (Acta Physica Polonica A 123, 1106 (2013)). The purpose of the present study was to investigate frequency discrimination of amplitude modulated high frequency carriers. Using 2AFC procedure, the subjects were presented with two observation intervals of which the first interval contained four pulses of the same high frequency signal (called SSSS), while in the second interval (called SHSH) the second and fourth pulses had higher frequencies values (i.e. shifted upwards by Δ f). The carrier frequency (in S pulses) was fixed and equal to 10 kHz. Modulation rates were equal to 100, 200, 337, 500, 600, 733, and 800 Hz. The value of the modulation rate was limited to keep all components of the sinusoidal modulation within one auditory filter (17% of the center frequency) centered at the carrier frequency. Two different types of modulation were used: a simple sinusoidal modulation with the modulation depth m set to 100%, and a logarithmic modulation with the modulation depth m set to 50 dB. Results indicate a strong relationship between frequency discrimination threshold and modulation type. The thresholds are significantly higher for logarithmic modulation in comparison to sinusoidal modulation. Amplitude modulation as well as logarithmic modulation applied to the high frequency carrier cause significant increase in the frequency discrimination threshold. For high frequency sinusoidal signal carriers (i.e. close to 10 kHz), frequency discrimination thresholds do not depend on amplitude modulation rates up to about 800 Hz. In general, the excitation pattern mechanism was a primary cue enabling frequency discrimination of modulated and unmodulated signals to compare with the mechanism based on the temporal fine structure. However, the excitation pattern was not the only mechanism responsible for the frequency discrimination.
    Źródło:
    Acta Physica Polonica A; 2014, 125, 4A; A-149-A-154
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Use of the Phase Locking Information in the Human Auditory System for Frequencies Above 5 kHz
    Autorzy:
    Sęk, A.
    Bukała, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1400102.pdf
    Data publikacji:
    2013-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    43.66.Fe
    43.66.Hg
    Opis:
    Accurate allocation of neural impulses to the same phase (i.e. phase locking) in the auditory system, ceases for frequencies above 5 kHz. However, some recent works suggest that it may have a much higher value. A discrimination of harmonic complex and inharmonic complex sound, formed using sound harmonic complex, in which all components were shifted towards higher frequency by the same number in hertzs, was analyzed. Fundamental frequency was $F_0$=1 kHz and signals were bandpass filtered by a fixed filter center frequency of which was $11F_0$ and bandwidth $5F_0$. Discrimination threshold was $\Delta F=0.089F_0$ for 10 normal-hearing subjects. However, replacing the sinusoidal components with the noise bands brought about a significant increase in thresholds. The largest increase was observed for 700 Hz bandwidth. The replacement of sinusoidal components with noisebands reduces information conveyed by phase locking. The differences in excitation pattern for harmonic complex and inharmonic complex signals, for the average threshold, did not exceed 0.7 dB. Therefore they could not be a useful cue for harmonic complex and inharmonic complex discrimination. A simplified model of phase locking showed that the substitution of sinusoids with bands of noise significantly reduced number of intervals between successive neural spikes corresponding to the virtual pitch of harmonic complex and inharmonic complex sounds. This degradation of discrimination suggests that the main source of information about the pitch of harmonic complex and inharmonic complex, especially for sinusoidal components, was the phase locking.
    Źródło:
    Acta Physica Polonica A; 2013, 123, 6; 1106-1113
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Binaural masking of amplitude modulation
    Autorzy:
    Kordus, M.
    Sęk, A.
    Kociński, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/177557.pdf
    Data publikacji:
    2005
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    masking
    masking in the modulation domain
    modulation filterbank
    Opis:
    A new concept concerned with the transformation of acoustic stimuli in the auditory system postulates the existence of a form of spectral analysis applied to the amplitude changes of the stimuli. It is assumed that this analysis takes place in the so-called modulation filters, i.e. bandpass linear filters tuned to different rates of the amplitude changes. The most striking argument supporting this idea is an effect of masking in the amplitude modulation domain whose nature can be easily explained basing on this concept. As the modulation filters are situated on the higher levels of the auditory system, it is also assumed that this form of masking is entirely a central process. However, most of the studies concerned with masking in the modulation domain used monaural listening only. Therefore, the main purpose of the presented here experiments was to investigate whether this type of masking is entirely a central process. Using a Three-Alternative Forced-Choice (3AFC) procedure the binaural and monaural masked thresholds of amplitude modulation were determined. A sinusoidal carrier at a frequency of 4 kHz was amplitude modulated by a specially designed band of noise characterized by a very low value of the crest factor, which was used as a masking signals. Different bandwidths of the modulating masking signals were used as well as different center frequencies to investigate whether the masking patterns in the modulation domain depend on the masker bandwidth and its center frequency. The modulating target (masked) signal was a pure tone at a frequency range from 2 to 256 Hz. Both modulating signals were applied to the same sinusoidal carrier signal. The most effective masking was noticed when the rate of the sinusoidal modulation was close to the center frequency of the masking signal or when it was in its spectral range and decreased outside of this range. The character of this dependence confirms the existence of some form of a frequency selectivity in the modulation rate domain similarly to the audible frequency domain. The thresholds for monaural and binaural listening were very close to each other. This implies that masking in the modulation domain is a central process.
    Źródło:
    Archives of Acoustics; 2005, 30, 1; 5-17
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Influence of the Semantic Material on the Assessment of Speech Reception Threshold
    Autorzy:
    Krenz, M.
    Wicher, A.
    Sęk, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/178107.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    speech intelligibility
    speech test
    speech reception threshold
    Opis:
    To determine speech intelligibility using the test suggested by Ozimek et al. (2009), the subject composed sentences with the words presented on a computer screen. However, the number and the type of these words were chosen arbitrarily. The subject was always presented with 18, similarly sounding words. Therefore, the aim of this study was to determine whether the number and the type of alternative words used by Ozimek et al. (2009), had a significant influence on the speech intelligibility. The aim was also to determine an optimal number of alternative words: i.e., the number that did not affect the speech reception threshold (SRT) and not unduly lengthened the duration of the test. The study conducted using a group of 10 subjects with normal hearing showed that an increase in the number of words to choose from 12 to 30 increased the speech intelligibility by about 0.3 dB/6 words. The use of paronyms as alternative words as opposed to random words, leads to an increase in the speech intelligibility by about 0.6 dB, which is equivalent to a decrease in intelligibility by 15 percentage points. Enlarging the number of words to choose from, and switching alternative words to paronyms, led to an increase in response time from approximately 11 to 16 s. It seems that the use of paronyms as alternative words as well as using 12 or 18 words to choose from is the best choice when using the Polish Sentence Test (PST).
    Źródło:
    Archives of Acoustics; 2015, 40, 1; 41-50
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Convolutive Blind Signal Separation Spatial Effectiveness in Speech Intelligibility Improvement
    Autorzy:
    Kociński, J.
    Sęk, A.
    Libiszewski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1504381.pdf
    Data publikacji:
    2011-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    43.72.-p
    43.60.-c
    43.60.+d
    Opis:
    Blind signal separation is one of the latest methods to improve the signal to noise ratio. The main objective of blind source separation is the transformation of mixtures of recorded signals to obtain each source signal at the output of the procedure, assuming that they are statistically independent. For acoustic signals it can be concluded that the correct separation is possible only if the source signals are spatially separated. That finding suggests analogies with the classical spatial filtering (beamforming). In this study we analyzed an effect of the angular separation of two source signals (i.e. speech and babble noise) to improve speech intelligibility. For this purpose, we chose the blind source separation algorithm based on the convolutive separation, based on second order statistics only. As a system of sensors a dummy head was used (one microphone inside each ear canal), which simulated two hearing aids of a hearing impaired person. The speech reception threshold, before and after the blind source separation was determined. The results have shown significant improvement in speech intelligibility after applying blind source separation (speach reception threshold fell even more than a dozen dB) in cases where the source signals were angularly separated. However, in cases where the source signals were coming from the same directions, the improvement was not observed. Moreover, the effectiveness of the blind source separation, to a large extent, depended on the relative positions of signal sources in space.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 6A; 996-999
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Influence of a Single Therapeutic Dose of Methadone on Selected Auditory Functions in Patients Addicted to Opioids and Undergoing Substitution Therapy – a Preliminary Study
    Autorzy:
    Tarnowska, E.
    Wicher, A.
    Sęk, A.
    Gorzelańczyk, E. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/176565.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    methadone
    opioids
    speech intelligibility
    otoacoustic emissions
    hearing threshold
    Opis:
    The main purpose of this research was to determine the influence of a therapeutic dose of an opioid drug (methadone) on selected auditory functions in patients addicted to opioids (recognition ICD-10; F11) and undergoing substitution therapy. Various hearing tests were used in this research – pure tone audiometry, impedance audiometry, otoacoustic emission measurement, and a speech in noise test – in two sessions, before and after methadone intake. It was found that methadone causes an improvement in speech intelligibility when speech is presented in speech-like noise, and slightly decreases hearing thresholds [dB HL]. Methadone consumption has no significant impact on distortion product otoacoustic emissions levels (DPOAE). In summary, a prescribed methadone dose does not worsen the hearing of opioid-dependent subjects.
    Źródło:
    Archives of Acoustics; 2018, 43, 1; 137-146
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Symulacje numeryczna procesu koalescencji w emulsjach spożywczych
    Numerical simulations of coalescence proces in food emulsions
    Autorzy:
    Sęk, J.
    Strzelecka, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/2071653.pdf
    Data publikacji:
    2011
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    emulsja
    koalescencja
    śmietankowanie
    symulacja numeryczna
    emulsions
    coalescence
    creaming
    numerical simulation
    Opis:
    Badano numerycznie proces koalescencji i śmietankowania w emulsjach. Stworzono modele numeryczne układów dwufazowych zawierających regularnie rozmieszczone krople fazy rozproszonej. Przeprowadzono symulacje zachowania się takich rojów w warunkach różnych wartości sił masowych i przy różnej średnicy kropel. Wykazano zgodność wyników uzyskanych za pomocą modeli numerycznych z wartościami wynikającymi z zależności teoretycznych. Stwierdzono również różny przebieg procesów śmietankowania i koalescencji w zależności od warunków przepływu.
    Coalescence and creaming of emulsions were investigated numerically. Numerical models of two-phase systems containing regularly distributed droplets of dispersed phase were created. Numerical simulation of flow and behavior of those systems of droplets were performed for different values of body forces and for different droplet diameter. It was proved that the numerical models were compatible with the theoretical equations. A different course of coalescence and creaming process was observed depending on flow conditions.
    Źródło:
    Inżynieria i Aparatura Chemiczna; 2011, 1; 41-42
    0368-0827
    Pojawia się w:
    Inżynieria i Aparatura Chemiczna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Badanie procesu nasiąkania struktur porowatych
    Investigation on imbibition of porous structures
    Autorzy:
    Sęk, J.
    Tryluk, M.
    Kucharek, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/2070553.pdf
    Data publikacji:
    2009
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    ciała porowate
    nasiąkanie
    równanie Washburna
    porous media
    imbibition
    Washburn equation
    Opis:
    Podjęto próbę zaproponowania zależności, które pozwalałyby z większą dokładnością niż powszechnie stosowane równanie Washbuna przewidywać przebieg procesu nasiąkania materiałów porowatych. Zaproponowano wykorzystanie czterech takich równań sprawdzając ich przydatność w oparciu o własne dane doświadczalne.
    An attempt was carried out to provide dependences that would allow one to predict a course of imbibition processes with higher accuracy then the commonly used Was/t6HrM equation. Four such formulae were proposed and yerified using own experimental data.
    Źródło:
    Inżynieria i Aparatura Chemiczna; 2009, 4; 112-113
    0368-0827
    Pojawia się w:
    Inżynieria i Aparatura Chemiczna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Badanie procesu przesiąkania wody przez warstwy ziarniste w warunkach nieustalonych
    Non-steady water percolation into granular beds
    Autorzy:
    Sęk, J.
    Stopczyk, A.
    Browarski, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/2070939.pdf
    Data publikacji:
    2010
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    warstwa ziarnista
    przesiąkanie wody
    opory przepływu
    granular beds
    percolation
    flow resistance
    Opis:
    Przeprowadzono badania procesu przesiąkania wody w warunkach nieustalonych przez warstwy ziarniste o różnej granulacji i różnej zawartości początkowej wilgoci. Wykazano, że proces ten może być podzielony na dwa etapy. W czasie pierwszego z nich zachodzi saturacja warstwy porowatej, a przebieg tego zjawiska ma charakter liniowy. Zaproponowany opis matematyczny pozwalający wyznaczyć prędkość wsiąkania w warstwę nieza-wierającą wilgoci. Przebieg drugiego etapu opisano za pomocą zależności potęgowej wprowadzając pojęcie współczynnika oporów przepływu, korzystając przy tym z zasad opisujących przebieg zjawisk grawitacyjnego wypływu cieczy ze zbiornika
    Investigations concerning the non-steady water percolation into granular beds were performed. Two process stages were distinguished. In the first one rising saturation of the bed occurred and it can be described using linear equations. The applied procedure aHowed one to determine the percolation velocity in beds during a dry state. The second process stage was described using the approach typical for gravitational flow from a tank. A concept of flow resistance coefficient was introduced.
    Źródło:
    Inżynieria i Aparatura Chemiczna; 2010, 2; 111-112
    0368-0827
    Pojawia się w:
    Inżynieria i Aparatura Chemiczna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optical Trapping and Propagation of Nonresonantly Driven One-Dimensional Exciton-Polariton Condensate
    Autorzy:
    Opala, A.
    Pieczarka, M.
    Sęk, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1033879.pdf
    Data publikacji:
    2017-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    67.85.De
    71.36.+c
    03.75.Kk
    Opis:
    We study theoretically a nonresonant optical creation of a one-dimensional exciton-polariton condensate in a semiconductor microcavity. The polariton condensate is treated in the mean-field approach, taking into consideration an antitrapping potential created by the reservoir of noncondensed particles. Polariton condensates are excited by multiple lasers, with a combination of continuous wave and pulsed sources. The proposed pump-probe configuration leads to the realisation of various experimental schemes, e.g. optical trapping of a polariton condensate in real space. Moreover, it can be utilised for investigation of elementary excitations in the time domain when polariton condensates from two sources interact with each other.
    Źródło:
    Acta Physica Polonica A; 2017, 132, 2; 401-404
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On a small Cochleosaurus described as a large Limnogyrinus [Amphibia, Temnospondyli] from the Upper Carboniferous of the Czech Republic
    Autorzy:
    Milner, A R
    Sequeira, S.E.K.
    Powiązania:
    https://bibliotekanauki.pl/articles/21039.pdf
    Data publikacji:
    2003
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Carboniferous
    Temnospondyli
    Limnogyrinus
    Czech Republic
    Amphibia
    Limnogyrinus elegans
    Cochleosaurus
    paleontology
    Upper Carboniferous
    Opis:
    Limnogyrinus elegans (Fritsch) is the most primitive micromelerpetontid temnospondyl from the Upper Carboniferous of Nýřany, Czech Republic. Arecent revision of the taxon by Werneburg (1994) attributed to this species a skull in dorsal aspect which was significantly larger than any previously reported and showed evidence of snout elongation. Restudy of this specimen demonstrates it to be a skull, visible in ventral aspect, of a juvenile of Cochleosaurus bohemicus, a more primitive edopoid temnospondyl, which is frequent in the Nýřany assemblage. Werneburg’s diagnosis of Limnogyrinusis revised and the problems of constructing ontogenetic series are discussed.
    Źródło:
    Acta Palaeontologica Polonica; 2003, 48, 1
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Revision of the amphibian genus Limnerpeton [Temnospondyli] from the Upper Carboniferous of the Czech Republic
    Autorzy:
    Milner, A R
    Sequeira, S.E.K.
    Powiązania:
    https://bibliotekanauki.pl/articles/22128.pdf
    Data publikacji:
    2003
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Temnospondyli
    Carboniferous
    Amphibia
    Czech Republic
    amphibian
    Limnerpeton
    paleontology
    Dissorophoidea
    Upper Carboniferous
    Opis:
    The Late Carboniferous amphibian genus Limnerpeton Fritsch, 1881 is revised on the basis of the type specimens of the eight original species described by Fritsch using material from Nýřany, Třemošná and Kounov, now in the Czech Republic. The type species Limnerpeton modestum is a nomen dubium restricted to a mandible that almost certainly belongs to an amphibamid temnospondyl but is not critically diagnostic. “Limnerpeton” laticeps and “Limnerpeton” macrolepis lectotypes are both small individuals of the same taxon as the later described Mordex calliprepes Steen, 1938 and thus form part of the hypodigm of Mordex laticeps comb. nov. “Limnerpeton” elegans is now Limnogyrinus elegans and is a member of the temnospondyl family Micromelerpetontidae. “Limnerpeton” obtusatum is a specimen of the microsaur Microbrachis pelikani. “Limnerpeton” dubium is an indeterminate tetrapod, probably either a temnospondyl or a pelycosaur. “Limnerpeton” difficile is a nomen dubium but the type is probably a small specimen of the tuditanomorph microsaur Crinodon limnophyes. “Limnerpeton” caducum is almost certainly a specimen of the ophiderpetontid aïstopod Oestocephalus granulosus. Several other described small temnospondyls from Nýřany are discussed and shown to be specimens of either Limnogyrinus elegans, Mordex laticeps or Amphibamidae incertae sedis. The tetrapod fauna at Nýřany includes four dissorophoid temnospondyls as proposed by Milner (1986) but with two changes in nomenclature. They comprise the branchiosaurid Branchiosaurus salamandroides, the micromelerpetontid Limnogyrinus elegans, the amphibamid Platyrhinops cf. lyelli and the primitive trematopid Mordex laticeps. These represent four of the five major dissorophoid families and demonstrate that the group had already diversified by the late Westphalian.
    Źródło:
    Acta Palaeontologica Polonica; 2003, 48, 1
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Phonon-Assisted Radiative Recombination of Excitons Confined in InAs Quantum Dashes
    Autorzy:
    Dusanowski, Ł.
    Musiał, A.
    Sęk, G.
    Machnikowski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1399092.pdf
    Data publikacji:
    2013-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.Hc
    63.20.kk
    Opis:
    In this report we have investigated theoretically the phonon-assisted recombination process of excitons confined in strongly elongated semiconductor nanostructures, called quantum dashes. Interaction with phonon bath leads to the occurrence of phonon-assisted recombination, which in the case of acoustic phonons is manifested in the optical spectra as a deviation of the homogeneously broadened emission line shape from expected Lorentzian profile via occurrence of the so-called phonon sidebands. Hereby, we have modeled the influence of the quantum dash geometry on this spectral feature proving pronounced suppression of phonon-induced decoherence for strongly elongated nanostructures. Furthermore, the importance of different phonon coupling mechanisms has been evaluated and the spectral diffusion effects, unavoidable in the time-integrated photoluminescence experiments, have been accounted for.
    Źródło:
    Acta Physica Polonica A; 2013, 124, 5; 813-816
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Badanie procesu przesiąkania roztworów olejów roślinnych i substancji ropopochodnych przez ośrodek porowaty
    Investigation of the percolation of the solutions of vegetable oils and crude oil derivatives through porous bed
    Autorzy:
    Sęk, J.
    Dziubiński, M.
    Błaszczyk, M.
    Padyk, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/401223.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Inżynierii Ekologicznej
    Tematy:
    przesiąkanie
    złoża porowate
    zanieczyszczenie gleb
    turbidymetria
    percolation
    porous bed
    turbidymetry
    Opis:
    Ropa naftowa i jej pochodne stanowią jedno z ważniejszych źródeł zanieczyszczeń gruntów i wód gruntowych. Postępująca industrializacja oraz rozwój motoryzacji są przyczyną większego zapotrzebowania na produkty naftowe. Wzrost wydobycia, przetwórstwa i zużycia ropy naftowej nieuchronnie pociąga za sobą zwiększenie przypadków zanieczyszczenia środowiska związkami ropopochodnymi. W pracy tej przedstawione zostały badania przesiąkania cieczy o różnych właściwościach fizykochemicznych przez warstwy ziarniste w warunkach nieustalonych. Podjęta została próba opisu zjawiska przesiąkania płynów modelowych za pomocą równań matematycznych uwzględniających wpływ lepkości cieczy na przebieg tego procesu. Podjęto także próbę oszacowania łatwości wymywania związków ropopochodnych z warstwy ziarnistej za pomocą wody.
    Crude oil and its derivatives are one of the major sources of pollution of land and groundwater. Increasing industrialization and development of automotive industry are causing a greater demand for oil products. The increase in mining, processing and consumption of oil will inevitably entail an increase in cases of environmental pollution with these compounds. In this work were presented penetration research liquids with different physical and chemical properties of granular layer in transients term. Attempt is made to describe the phenomenon of percolation fluid models using mathematical equations taking into account the effect of viscosity on this process. An attempt to estimate the ease of leaching of petroleum compounds from the granular layer by water. The aim of this study was to determine the efficiency of migration processes of high-viscosity substance in the soil.
    Źródło:
    Inżynieria Ekologiczna; 2011, 26; 48-58
    2081-139X
    2392-0629
    Pojawia się w:
    Inżynieria Ekologiczna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Electronic Structure of Elongated $In_{0.3}Ga_{0.7}As//GaAs$ Quantum Dots
    Autorzy:
    Pieczarka, M.
    Musiał, A.
    Podemski, P.
    Sęk, G.
    Misiewicz, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1399091.pdf
    Data publikacji:
    2013-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.Hc
    73.21.La
    73.22.-f
    Opis:
    In this contribution the electronic structure of large $In_{0.3}Ga_{0.7}As//GaAs$ quantum dots is studied theoretically by means of 8 band k · p modeling. These quantum dots constitute unique physical system due to the low strain limit of the Stranski-Krastanow growth mode resulting in relatively large physical volume and elongation of the quantum dots in [1-10] direction. As a result of these critical growth conditions the electronic structure is expected to be very sensitive to the nanostructure size, shape, and composition of the quantum dot as well as the accompanying wetting layer. Another peculiarity of investigated system is the confining potential which is rather shallow and weakened in comparison to standard quantum dots. It makes them very interesting in view of both fundamental study and potential applications. To reveal physical mechanisms determining the optical properties of the investigated system, the electronic structure, mainly the number of confined states, and the wave function extension as a function of both quantum dot size and geometry have been simulated numerically and the importance of electron-hole Coulomb interactions has been evaluated.
    Źródło:
    Acta Physica Polonica A; 2013, 124, 5; 809-812
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of Confinement Anisotropy on Excitonic Properties in InAs/InP Quantum Dashes
    Autorzy:
    Mrowiński, P.
    Musiał, A.
    Sęk, G.
    Misiewicz, J.
    Höfling, S.
    Somers, A.
    Hein, S.
    Forchel, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1399087.pdf
    Data publikacji:
    2013-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.-y
    71.70.Gm
    78.67.Hc
    73.21.-b
    81.07.Ta
    Opis:
    The influence of confinement potential anisotropy on emission properties of strongly elongated single InAs/InGaAlAs/InP quantum dashes has been investigated by polarization-resolved microphotoluminescence spectroscopy at around 1.5 μm. There have been determined the exciton fine structure splitting, degree of linear polarization of surface emission and biexciton binding energy. The investigated dashes exhibited usually: the exciton anisotropy splitting larger than 100 μeV, the corresponding biexciton binding energy of about 3 meV, and the degree of linear polarization values in the range from 24% to 55%. Here, we presented a correlation of these parameters for several quantum dashes, which can be attributed either to a change in lateral aspect ratio within the ensemble, or the carrier localization on random fluctuations of the dash confinement potential.
    Źródło:
    Acta Physica Polonica A; 2013, 124, 5; 801-804
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optical, Structural, and Electrical Properties of Aromatic Triphenylamine-Based Poly(azomethine)s in Thin Layers
    Autorzy:
    Palewicz, M.
    Iwan, A.
    Sikora, A.
    Doskocz, J.
    Strek, W.
    Sek, D.
    Mazurek, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1490096.pdf
    Data publikacji:
    2012-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    77.84.Jd
    73.61.Ph
    78.66.Qn
    Opis:
    Spectroscopic and photophysical properties of the poly(azomethine)s with triphenylamine moieties were investigated by UV-vis, X-ray diffraction and atomic force microscopy methods. Current-voltage measurements were performed on ITO/polymer/$Alq_3$/Al, ITO/PEDOT/polymer:MWCNT/Al and ITO/polymer:MWCNT/Al devices. Multiwall carbon nanotubes were blended with polymer in the ratio 1:1. The lowest optical band gap value at 2.33 eV was detected. Moreover, an absorption coefficient α was calculated from transmission and reflectivity measurements. In this paper, we presented photophysical and structural properties of the poly(azomethine)s in solid state of great interest for the emerging field of molecular electronics and for their uses as active layers in (opto)electronic devices such as solar cells.
    Źródło:
    Acta Physica Polonica A; 2012, 121, 2; 439-444
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of Built-in Electric Field on Forbidden Transitions in In_xGa$\text{}_{1-x}$As/GaAs Double Quantum Well by Three-Beam Photoreflectance
    Autorzy:
    Sęk, G.
    Ryczko, K.
    Misiewicz, J.
    Bayer, M.
    Wang, T.
    Forchel, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/2028844.pdf
    Data publikacji:
    2001-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.20.-r
    78.66.-w
    Opis:
    Photoreflectance spectroscopy has been used to study optical transitions in In$\text{}_{0.045}$Ga$\text{}_{0.955}$As/GaAs double quantum well at 80 K. The derivative nature of this contactless electromodulation technique allows for the observation of excited state transitions in the low-dimensional structure including the symmetry-forbidden ones. Excitonic symmetry-forbidden transitions can be observed due to the effect of mixing of heavy and light hole excitons and/or due to some asymmetry in the structure. We have shown that the built-in electric field in the region of double quantum well is weak enough (less than 0.5 kV/cm) not to cause any significant energetic shift of features due to quantum confined Stark effect, on one hand. On the other hand, it is sufficient to change strongly the oscillator strength of forbidden transitions. To change the internal electric field, we have used photoreflectance in the three-beam mode with a third beam continuously illuminating the sample and causing changes of the built-in electric fields due to the photovoltage effect. This method works as a contactless forward bias and allows for a change of the field down to the flat band conditions. We have shown that changes of built-in electric field by amount of a few tenths of kV/cm can modify the intensity of forbidden transitions significantly. We show that, although the mixing of excitons is still important, a very weak built-in electric field can be dominant in the observation of forbidden excitonic transitions in double quantum well.
    Źródło:
    Acta Physica Polonica A; 2001, 100, 3; 417-424
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Hole Subband Mixing and Polarization of Luminescence from Quantum Dashes: A Simple Model
    Autorzy:
    Kaczmarkiewicz, P.
    Musiał, A.
    Sęk, G.
    Podemski, P.
    Machnikowski, P.
    Misiewicz, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/2048063.pdf
    Data publikacji:
    2011-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.Hc
    73.22.-f
    Opis:
    In this paper, we address the problem of luminescence polarization in the case of nanostructures characterized by an in-plane shape asymmetry. We develop a simple semi-qualitative model revealing the mechanism that accounts for the selective polarization properties of such structures. It shows that they are not a straightforward consequence of the geometry but are related to it via valence subband mixing. Our model allows us to predict the degree of polarization dependence on the in-plane dimensions of investigated structures assuming a predominantly heavy hole character of the valence band states, simplifying the shape of confining potential and neglecting the influence of the out-of-plane dimension. The energy dependence modeling reveals the importance of different excited states in subsequent spectral ranges leading to non-monotonic character of the degree of polarization. The modeling results show good agreement with the experimental data for an ensemble of InAs/InP quantum dashes for a set of realistic parameters with the heavy-light hole states separation being the only adjustable one. All characteristic features are reproduced in the framework of the proposed model and their origin can be well explained and understood. We also make some further predictions about the influence of both the internal characteristics of the nanostructures (e.g. height) and the external conditions (excitation power, temperature) on the overall degree of polarization.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 5; 633-636
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Temperature Dependence of Photoluminescence from Epitaxial InGaAs/GaAs Quantum Dots with High Lateral Aspect Ratio
    Autorzy:
    Musiał, A.
    Sęk, G.
    Maryński, A.
    Podemski, P.
    Misiewicz, J.
    Löffler, A.
    Höfling, S.
    Reitzenstein, S.
    Reithmaier, J.
    Forchel, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1492876.pdf
    Data publikacji:
    2011-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.Hc
    65.80.-g
    Opis:
    Hereby, we present a study of a thermal quenching of emission from self-assembled epitaxial highly asymmetric quantum dots in InGaAs/GaAs material system for both ensemble and single dot regime. Pronounced interplay between the intensity of wetting layer and quantum dots originated emission was observed as the temperature was increased, evidencing a thermally activated energy transfer between the two parts of the system and an important role of the wetting layer in determining the optical properties of these anisotropic nanostructures. The carrier activation energies have been derived and possible carrier loss mechanisms have been analyzed. Single dot study revealed activation energies slightly varying from dot to dot due to size and shape distribution. The problem of the shape uniformity of individual quantum dot has also been addressed and possibility of additional carrier localization within the investigated structures has been found to be insignificant based on the recorded spectroscopic data.
    Źródło:
    Acta Physica Polonica A; 2011, 120, 5; 883-887
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    InAs on InP Quantum Dashes as Single Photon Emitters at the Second Telecommunication Window: Optical, Kinetic, and Excitonic Properties
    Autorzy:
    Mrowiński, P.
    Dusanowski, Ł.
    Somers, A.
    Höfling, S.
    Reithmaier, J.
    Misiewicz, J.
    Sęk, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1033861.pdf
    Data publikacji:
    2017-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    photoluminescence
    quantum dash
    excitonic complexes
    antibunching
    autocorrelation
    single photon source
    telecommunication
    time-resolved
    Opis:
    In this work, InAs/InGaAlAs/InP quantum dashes have been investigated in terms of their optical, kinetic, and excitonic properties with respect to their application within the 1300± 40 nm spectral range, i.e. the O-band of the telecommunication technologies. We focused on the basic excitonic complexes such as neutral exciton, biexciton, and charged exciton, which have been identified by means of photoluminescence measurements. Emission and carriers' dynamics have been analyzed using rate equation model and fitting the experimental data obtained for both continuous-wave and pulsed excitation regimes. There has been found a significant impact of the charge carrier imbalance in the system and electron capturing rate on the dynamics of the optical and electronic transitions, which results in a high occupation of the negatively charged trion state. Autocorrelation measurements show clear antibunching of trion emission for non-resonant excitation which indicates a potential of such kind of emitters as single photon sources for short-range quantum communication schemes.
    Źródło:
    Acta Physica Polonica A; 2017, 132, 2; 382-386
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Energy Transfer Processes in InAs/GaAs Quantum Dot Bilayer Structure
    Autorzy:
    Pieczarka, M.
    Maryński, A.
    Podemski, P.
    Misiewicz, J.
    Spencer, P.
    Murray, R.
    Sęk, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1185237.pdf
    Data publikacji:
    2016-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.Hc
    71.35.-y
    78.55.-m
    Opis:
    We investigate double layer InAs/GaAs quantum dots grown in the Stransky-Krastanov mode by molecular beam epitaxy. The sample consists of two layers of InAs quantum dots separated by 10 nm thick GaAs layer, where the top quantum dot layer of an improved homogeneity is covered by an InGaAs cap. This configuration has allowed for the extension of the dots' emission to longer wavelengths. We probed the carrier transfer between the states confined in a double quantum well composed of InGaAs cap and the quantum dots wetting layer to the states in the quantum dots by means of photoluminescence excitation and photoreflectance spectroscopies. Efficient emission from quantum dots excited at the double quantum well ground state energy was observed. There is also presented a discussion on the carrier injection efficiency from the capping layer to the quantum dots.
    Źródło:
    Acta Physica Polonica A; 2016, 129, 1a; A-59-A-61
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Oscillator strength of optical transitions in InGaAsN/GaAsN/GaAs quantum wells
    Autorzy:
    Mika, A
    Sek, G
    Ryczko, K
    Kozub, M
    Musial, A
    Marynski, A
    Misiewicz, J
    Langer, F
    Höfling, S
    Appel, T
    Kamp, M
    Forchel, A
    Powiązania:
    https://bibliotekanauki.pl/articles/173586.pdf
    Data publikacji:
    2013
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    dilute nitride
    quantum well
    oscillator strength
    Opis:
    Experimental and theoretical considerations and results on the effect of nitrogen incorporation on the oscillator strength of optical transitions in InGaNAs/GaAs quantum wells (QWs) are presented. Therefore, a set of dilute nitride quantum well structures was grown by molecular beam epitaxy. Optical investigation via spectroscopic methods have been performed at various temperatures for both the as-grown samples, and after rapid thermal annealing. The fundamental transition energy and its oscillator strength vs. the QW composition have been systematically investigated. Additionally, the effect of the bandgap discontinuities on the transitions intensity has also been considered. The experimental data have been confronted with the band structure calculations within the effective mass approximation employing a two level repulsion model for the nitrogen-containing structures. The obtained results are crucial for possible future applications employing the quantum well in cavity structures and bringing the practical exploitation of quantum electrodynamics phenomena to the telecommunication spectral range.
    Źródło:
    Optica Applicata; 2013, 43, 1; 53-60
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    GaAs-Based Quantum Well Exciton-Polaritons beyond 1 μm
    Autorzy:
    Pieczarka, M.
    Podemski, P.
    Musiał, A.
    Ryczko, K.
    Sęk, G.
    Misiewicz, J.
    Langer, F.
    Höfling, S.
    Kamp, M.
    Forchel, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1399094.pdf
    Data publikacji:
    2013-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.21.-b
    78.67.-n
    78.67.Pt
    Opis:
    Realization of the Bose-Einstein condensate can provide a way for creation of an inversion-free coherent light emitter with ultra-low threshold power. The currently considered solutions provide polaritonic emitters in a spectral range far below 1 μm limiting their application potential. Hereby, we present optical studies of InGaAs/GaAs based quantum well in a cavity structure exhibiting polaritonic eigenmodes from 5 to 160 K at a record wavelength exceeding 1 μm. The obtained Rabi splitting of 7 meV was almost constant with temperature, and the resulting coupling constant is close to the calculated QW exciton binding energy. This indicates the very strong coupling conditions explaining the observation of polaritons at temperatures where the exciton dissociation is already expected, and allows predicting that room temperature polaritons could still be formed in this kind of a system.
    Źródło:
    Acta Physica Polonica A; 2013, 124, 5; 817-820
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimizing the InGaAs/GaAs quantum dots for 1.3 μm emission
    Autorzy:
    Maryński, A.
    Mrowiński, P.
    Ryczko, K.
    Podemski, P.
    Gawarecki, K.
    Musiał, A.
    Misiewicz, J.
    Quandt, D.
    Strittmatter, A.
    Rodt, S.
    Reitzenstein, S.
    Sęk, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1055140.pdf
    Data publikacji:
    2017-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.30.Fs
    78.67.-n
    78.67.Hc
    73.22.-f
    Opis:
    Hereby we present comprehensive experimental and theoretical study on fundamental optical properties and electronic structure of GaAs-based quantum dots grown using metalorganic chemical vapor deposition technique. The substantial redshift of emission, to the second telecommunication window of 1.3 μm, in comparison to standard InGaAs/GaAs quantum dots is obtained via strain engineering utilizing additional capping layer of In_{0.2}Ga_{0.8}As in this context referred to as strain reducing layer. It ensures lowering of the energy of the ground state transition to more application relevant spectral range. Optical properties of the quantum dot structure has been experimentally characterized by means of photoreflectance spectroscopy and power-dependent photoluminescence revealing 3 transitions originating from hybrid states confined in an asymmetric double quantum well formed of the wetting layer and strain reducing layer, as well as higher states of the quantum dots themselves with the first excited state transition separated by 67 meV from the ground state transition. Origin of the observed transitions was confirmed in theoretical modelling using 1-band single-particle approach for the quantum well part, and excitonic quantum dot spectrum obtained within 8 band k·p formalism followed by configuration interaction calculations, respectively. Additionally, photoluminescence excitation spectroscopy measurements allowed to identify a spectral range for efficient quasi-resonant excitation of the investigated quantum dots into the 2D density of states to be in the range of 835-905 nm.
    Źródło:
    Acta Physica Polonica A; 2017, 132, 2; 386-390
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Peculiarities in optical response of hybrid-barrier GaSb/InAs/AlSb resonant tunneling diode structure
    Autorzy:
    Dyksik, M.
    Motyka, M.
    Rygała, M.
    Pfenning, A.
    Hartmann, F.
    Weih, R.
    Worschech, L.
    Höfling, S.
    Sęk, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1835778.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    resonant tunneling diode
    quantum well
    optical spectroscopy
    photoluminescence
    photoreflectance
    Opis:
    We present comprehensive investigation of the optical properties of hybrid-barrier GaSb-based resonant tunneling structures, containing a bulk-like GaInAsSb absorption layer and two asymmetric type II GaSb/InAs/AlSb quantum wells. Methods of optical spectroscopy by means of Fourier-transformed photoluminescence and photoreflectance are employed to probe optical transitions in this complex multilayer system. Based on the comparison between the absorption-like and emission-like spectra (also in function of temperature) confronted with band structure calculations four main transitions could be resolved and identified. For one of them, there has been observed unusually strong linear polarization dependence never reported in structures of that kind. It has been interpreted as related to a transition at the GaSb/GaInAsSb interface, for which various scenarios causing the polarization selectivity are discussed.
    Źródło:
    Optica Applicata; 2021, 51, 2; 171-180
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigation of the Non-Square InGaAsP/InP Quantum Wells in the Electric Field by Photoreflectance
    Autorzy:
    Kudrawiec, R.
    Sęk, G.
    Rudno-Rudziński, W.
    Misiewicz, J.
    Wojcik, J.
    Robinson, B. J.
    Thompson, D. A.
    Mascher, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/2035600.pdf
    Data publikacji:
    2002
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.63.Hs
    78.67.-n
    66.10.Cb
    Opis:
    Non-square quantum wells in electric field have been investigated by photoreflectance and photoluminescence spectroscopies. The structures have been obtained by a post-growth modification (rapid thermal annealing) of standard 1.55μm InGaAsP-based laser structures that were grown by gas source molecular beam epitaxy. During rapid thermal annealing a migration of semiconductor atoms across quantum well interfaces changes the quantum well profile from a square well to a rounded well. The modification of the profile changes energy levels in the quantum well and in consequence a blue shift of the quantum well emission peak is observed in photoluminescence. In this paper the blue shift of the ground state transition of post-growth modified quantum well structures has been investigated by both photoluminescence and photoreflectance techniques. Also a blue shift of excited state transitions has been observed in photoreflectance spectra. Generally, a stronger blue shift for the ground state transition than for excited state transitions has been observed. Additionally, oscillator strengths for all quantum well transitions have been determined from photoreflectance spectra. It has been found that the oscillator strength is constant for all quantum well transitions despite of modification of the quantum well profile.
    Źródło:
    Acta Physica Polonica A; 2002, 102, 4-5; 649-657
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of dielectric medium anisotropy on the polarization degree of emission from a single quantum dash
    Autorzy:
    Mrowiński, P.
    Tarnowski, K.
    Olszewski, J.
    Somers, A.
    Kamp, M.
    Höfling, S.
    Reithmaier, J.
    Urbańczyk, W.
    Misiewicz, J.
    Machnikowski, P.
    Sęk, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1159588.pdf
    Data publikacji:
    2016-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.Hc
    71.35.-y
    78.55.-m
    Opis:
    Excitonic emission from single InAs/InGaAlAs/InP quantum dashes has been investigated in the context of degree of linear polarization by post-growth modification of its surrounding dielectric medium. We present optical spectroscopy measurements on a symmetric squared pedestal structures (mesas), and asymmetric rectangular ones oriented parallel or perpendicular to the main in-plane axis of the dashes [1-10]. Polarization resolved microphotoluminescence shows a significant quantitative modification of the degree of linear polarization value from -20% up to 70%. These results have been confronted with calculations of the coupling between the exciton transition dipole moment and electromagnetic field distributed in the vicinity of a quantum dash inside a processed mesa.
    Źródło:
    Acta Physica Polonica A; 2016, 129, 1a; A-48-A-52
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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