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Wyświetlanie 1-11 z 11
Tytuł:
Influence of InGaN waveguide on injection efficiency in III-nitride laser diodes
Autorzy:
Hajdel, Mateusz
Muzioł, Grzegorz
Nowakowski-Szkudlarek, Krzesimir
Siekacz, Marcin
Wolny, Paweł
Skierbiszewski, Czesław
Powiązania:
https://bibliotekanauki.pl/articles/173219.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
InGaN
laser diode
waveguide
injection efficiency
Opis:
The influence of using InGaN waveguides on blue laser diodes was theoretically studied using 1D drift diffusion model and 2D optical mode calculation. Despite of the known effect of increased confinement of an optical mode, especially for long wavelengths, an unexpected influence on the efficiency of carrier injection into the active region is discussed. It is found that InGaN-AlGaN interface is crucial to achieving high injection efficiency. A numerical model is created, which describes the influence of InGaN waveguide and Mg doping of electron blocking layer on basic properties of laser diodes. It is found that an increase of injection efficiency allows to reduce the doping level in an electron blocking layer and take advantage of decreased optical losses.
Źródło:
Optica Applicata; 2020, 50, 2; 311-321
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Emission-intensity-enhanced GaN-based LED based on multilayer grating structures
Autorzy:
Li, Xin
Sun, Dejie
Han, Kun
Cao, Lijun
Guo, Shiliang
Li, Zhiquan
Powiązania:
https://bibliotekanauki.pl/articles/2033893.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
light-emitting diode
surface plasmon
grating
quantum well
Opis:
A novel surface-plasmon-enhanced GaN-LED is proposed to improve the emission efficiency of the traditional LED. The SiO2 film, Ag triangular structure and ITO film were coated on the rectangularly-patterned p-GaN layer sequentially, which can form the quasi-symmetrical waveguide structure to enhance the internal quantum efficiency and the light extraction efficiency. The COMSOL software is used to simulate the LED structure. The radiated powers, absorbed powers and distribution of electric field are obtained and analyzed. The results reveal that emission efficiency of the proposed GaN-LED can be greatly improved.
Źródło:
Optica Applicata; 2021, 51, 4; 529-540
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
How to enhance a room-temperature operation of diode lasers and their arrays
Autorzy:
Sarzała, R. P.
Sokół, A. K.
Kuc, M.
Nakwaski, W.
Powiązania:
https://bibliotekanauki.pl/articles/174004.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
diode laser
thermal management
thermal crosstalk
semiconductor arrays
Opis:
A key problem to be solved during designing productive diode lasers and their lasing arrays is their proper thermal management enabling efficient high-power operation. Strictly speaking, the above demand leads to optimization of their structures to enhance lasing performance for high operation currents. It is well-known that deterioration of laser performance is mostly induced by excessive temperature increases within their volumes. In diode-laser arrays, additionally thermal crosstalk between array emitters should be taken into account. In the present paper, physics of heat-flux generation within the laser-diode volume and its extraction from it is analysed and described with the aid of our self-consistent simulation procedure. Then their thermal optimization is discussed including a proper design of a heat-flux generation within the laser volume, enhancement of its transport towards a laser heat-sink and, additionally in laser arrays, reduction of a thermal crosstalk between individual array emitters. The analysis is carried out using modern nitride edge-emitting ridge-waveguide lasers and their one-dimensional arrays as well as arsenide semiconductor disk lasers as typical examples of modern diode-laser designs. Physical processes responsible for heat-flux generation within these devices and heat-flux extraction from their volumes are analysed and an impact of some construction details on these processes is explained.
Źródło:
Optica Applicata; 2016, 46, 2; 213-226
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
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:
Delayed differential detection for absorption spectroscopy recovery
Autorzy:
Cong, Menglong
Sun, Dandan
Powiązania:
https://bibliotekanauki.pl/articles/173211.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wavelength modulation spectroscopy
WMS
absorption
derivative spectrum
harmonic detection
laser diode
Opis:
An elaborately designed system has been devoted to the recovery of the line shape function of absorption spectrum. Laser power passing through trace gas has been divided into the real-time and delayed components, and their difference, i.e. the equivalent of the first-order derivative spectrum, is recorded and integrated to reconstruct the absorption line profile. Since the real-time and delayed signals are derived from the only gas cell and photodetector, the elimination of background is more effective, relative to the general used double beam detection that involves two gas cells and photodetectors. Compared with the 1st harmonic detection used in the wavelength modulation spectroscopy, here the generation of derivative spectrum is achieved without modulating the injection current of laser. Additionally, the expensive lock-in amplifier working for wavelength modulation spectroscopy is replaced by a homemade device, which is made of an all-pass filter and an instrumentation amplifier. Therefore, the complexity and cost are significantly reduced, and the stability is improved. For the purpose of validation, recovering of the absorption spectroscopy is carried out using a methane sample at its R(3) absorption line of the 2ν3 overtone, and the obtained data are found to be in a high agreement with theoretical deductions.
Źródło:
Optica Applicata; 2019, 49, 2; 303-315
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigation of the two-dimensional gas temperature distribution based on tunable diode laser absorption spectroscopy
Autorzy:
Shao, J
Wang, L
Ying, C
Powiązania:
https://bibliotekanauki.pl/articles/174322.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
tomographic
modified adaptive algebraic reconstruction technique (MAART)
tunable diode laser absorption spectroscopy (TDLAS)
Opis:
Based on tunable diode laser absorption spectroscopy and modified adaptive algebraic reconstruction technique, two-dimensional tomographic reconstruction was derived for the gas temperature distribution in the range of 600–1400 K in the controlled projections. It is explicitly shown that the quality of temperature reconstruction is heavily dependent on the relative sensitivity of the selected spectrum and the algorithm of modified adaptive algebraic reconstruction technique but independent of the complexity of the present field distribution. When the relative sensitivity is less than 1.5, the accuracy of reconstruction relates to the relative sensitivity of the selected spectrum and improves with the increase in relative sensitivity. When the relative sensitivity is larger than 1.5, the accuracy is mainly limited by the algorithm of modified adaptive algebraic reconstruction technique.
Źródło:
Optica Applicata; 2015, 45, 2; 183-198
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multiple fiber Bragg grating sensing system based on active mode-locking fiber laser
Autorzy:
Meng, Delong
Yu, Xiaolei
Zhao, Zhimin
Shan, Shilei
Li, Hongzhe
Powiązania:
https://bibliotekanauki.pl/articles/2172831.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fibre optics
Fabry-Perot laser diode
fibre laser
active mode-locking
fibre Bragg grating
Opis:
In this paper, a new multiple fiber Bragg grating (FBG) sensing system based on active mode-locking fiber laser is proposed. The active mode-locking fiber laser is composed of a linear cavity with an Fabry–Perot laser diode (F-P LD) as a reflective cavity mirror, and the erbium-doped fiber as the gain medium. Meanwhile, the F-P LD is also used as the modulating element of the fiber laser. Multiple FBGs cascaded in a long fiber are used as both the sensors in the system and the components for wavelength selection in the active mode-locking fiber laser. The capacity of the proposed sensing system to interrogate multiple FBGs in wavelength and spatial domain is investigated. The proposed sensing system has the characteristics of low cost, good stability, good compatibility, and can be used in quasi-distributed multi-point sensing.
Źródło:
Optica Applicata; 2022, 52, 3; 375--384
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of technology of diode laser mirror processing to maximize the threshold of catastrophic optical degradation
Autorzy:
Dąbrowska, Elżbieta
Teodorczyk, Marian
Szymański, Michał
Maląg, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/1835816.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
laser diode
catastrophic optical damage
COD
laser mirror
semiconductor surface passivation
optical coating
electroluminescence
Opis:
In this paper, optimization works on the technology of passivation and optical coatings of laser diode facets are described. The main goal is to increase the optical power at which the catastrophic optical mirror damage occurs. The coatings and passivation processes have been done in an ion source-aided electron-beam evaporator. The essence of passivation was to remove native oxides and produce a native thin nitride layer with simultaneous saturation of the dangling atomic bonds. The procedure has been realized with the help of nitrogen or forming gas (N2 + H2) beam. As a result, we present sets of technological parameters allowing to increase the catastrophic optical mirror damage threshold of diode lasers.
Źródło:
Optica Applicata; 2020, 50, 4; 593-607
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensitive detection of acetylene by second derivative spectra with tunable diode laser absorption spectroscopy
Autorzy:
Deng, H.
Sun, J.
Li, P.
Liu, Y.
Yu, B.
Li, J.
Powiązania:
https://bibliotekanauki.pl/articles/174963.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
tunable diode laser absorption spectroscopy
TDLAS
signal processing
Savitzky–Golay filter
trace gas detection
Opis:
A tunable diode laser absorption spectrometer was developed for trace acetylene gas analysis, the system performance was evaluated by combing an appropriate digital signal processing methods, i.e., Savitzky–Golay smoothing and differentiation algorithm. The calculation of the derivative spectra by this method is accompanied by simultaneous data smoothing. Based on the 2nd deriv- ative spectra detection method, the Allan variance technique indicates a C2H2 detection limit of 1.7ppm for 1-s averaging time, and a minimum noise level of 62ppb (parts per billion), at the optimum integration time of ~60s. The calculated 2nd derivative spectra with better resolution, lower detection limits, save signal processing time, and improve the ability to distinguish unresolved spectral signals.
Źródło:
Optica Applicata; 2016, 46, 3; 353-363
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of a weak ion beam treatment of emission layer on the top emission polymer light-emitting diode
Autorzy:
Gong, T
Gwag, J S
Powiązania:
https://bibliotekanauki.pl/articles/174367.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
organic light emitting diode
light-emitting polymer
top emission
optical device
ion beam
surface treatment
Opis:
This study examined the influence of a weakly treated emission layer on ion beam processing for the performance of top emission polymer light-emitting diodes with an invert structure (top ITO as the anode). The emission layer used in this experiment was a polymer type SY, Livilux PDY-132 provided by Merck & Co. The surface of the emission layer was modified by a low energy ion beam treatment to obtain hydrophilic functional groups and improve the wettability. As a hole transfer layer, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS, CLEVIOS AI 4083, Heraeus) was spin-coated on the ion beam treated emission layer and showed good adhesion properties. Consequently, through such an ion beam treatment that promotes the interface properties of these two layers, a uniform light emitting area was obtained and the light intensity in a top emission polymer light-emitting diode was improved.
Źródło:
Optica Applicata; 2014, 44, 4; 567-574
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A diode-pumped high-repetition-frequency passively Q-switched Nd:LaMgAl11O19 laser
Autorzy:
Xu, Yan
Gao, Ziye
Xia, Guangqiong
Wu, Zhengmao
Powiązania:
https://bibliotekanauki.pl/articles/1835801.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Nd:LaMgAl11O19 disordered crystal
Q-switched laser
high pulse repetition frequency
PRF
semiconductor saturable absorber mirror
SESAM
laser diode
LD
Opis:
High-repetition-frequency Q-switched laser is realized through adopting a Nd:LaMgAl11O19 (Nd:LMA) disordered crystal as the gain material, a laser diode lasing at 796 nm as the pumped source, and a semiconductor saturable absorber mirror (SESAM) as the Q-switched device. The out-put characteristics are analyzed under using different transmittance T plane mirrors as an output coupler. Without adopting SESAM, the laser is operating at a CW state, and a relatively high transmittance is helpful for achieving high output power, slope efficiency and light-to-light efficiency. ForT = 7.5% and an absorbed power of 6.17 W, the output power arrives at its maximum of 1160 mW,and the corresponding slope efficiency and light-to-light efficiency are 20.71% and 18.78%, respectively. After introducing SESAM into the cavity, the laser operates at a passively Q-switched state, and the largest slope efficiency is 13.14% under T = 5.0%. Adopting five different output couplers, with the increase of the absorbed power, the pulse repetition frequencies, the pulse energies and the peak powers will ascend while the pulse widths will decline. The observed narrowest pulse width, the maximum pulse repetition frequency, the highest pulse energy and peak power are 1.745 μs, 175.88 kHz, 3.21 μJ and 1.84 W, respectively.
Źródło:
Optica Applicata; 2020, 50, 3; 415-423
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-11 z 11

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