- Tytuł:
- Study of thin, achromatic diffractive structures to focus terahertz radiation on a detector
- Autorzy:
-
Liebert, Karolina
Rachon, Martyna
Kolodziejczyk, Andrzej
Sypek, Maciej
Ducin, Izabela
Zagrajek, Przemysław
Siemion, Agnieszka - Powiązania:
- https://bibliotekanauki.pl/articles/1835798.pdf
- Data publikacji:
- 2020
- Wydawca:
- Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
- Tematy:
-
terahertz
diffractive optics
axicon
high order kinoform
spherical lens
light sword optical element
chromatic aberration - Opis:
- Thin and lightweight achromatic focusing elements with F-number close to 1 are desirable in many practical applications. We present the idea to use diffractive structures designed to work for the substantially increased THz frequency range. The paper analyses mono- and multi-focal lenses forming point-like foci as well as axicon and light sword optical elements focusing THz radiation into line segments located along the optical axis. We consider diffractive elements in a form of the first and the second order kinoforms having various thicknesses. Designed and fabricated elements were numerically and experimentally examined to verify their achromatic functioning. We present point spread functions (XY scans) and 2D energy maps (XZ scans) for different THz frequencies. Moreover, a diagram of chromatic aberration is created by registering energy distribution along the optical axis for different frequencies. The distance corresponding to the highest energy is chosen for each frequency. Therefore, we can compare broadband working of designed structures. The spherical lens coded as kinoform of the second order provides the best broadband functioning, however it is two times thicker than structures providing extended depth of focus (light sword and axicon) working with slightly smaller efficiency but being much thinner.
- Źródło:
-
Optica Applicata; 2020, 50, 3; 463-476
0078-5466
1899-7015 - Pojawia się w:
- Optica Applicata
- Dostawca treści:
- Biblioteka Nauki
Artykuł