TY  - JOUR
A1  - Schade, A.
A1  - Bader, A.
A1  - Huber, T.
A1  - Kuhn, S.
A1  - Czyszanowski, T.
A1  - Pfenning, A.
A1  - Rygała, M.
A1  - Smołka, T.
A1  - Motyka, M.
A1  - Sęk, G.
A1  - Hartmann, F.
A1  - Höfling, S.
T1  - Monolithic high contrast grating on GaSb/AlAsSb based epitaxial structures for mid-infrared wavelength applications
JF  - Optics Express
N2  - We demonstrate monolithic high contrast gratings (MHCG) based on GaSb/AlAs0.08Sb0.92 epitaxial structures with sub-wavelength gratings enabling high reflection of unpolarized mid-infrared radiation at the wavelength range from 2.5 to 5 µm. We study the reflectivity wavelength dependence of MHCGs with ridge widths ranging from 220 to 984 nm and fixed 2.6 µm grating period and demonstrate that peak reflectivity of above 0.7 can be shifted from 3.0 to 4.3 µm for ridge widths from 220 to 984 nm, respectively. Maximum reflectivity of up to 0.9 at 4 µm can be achieved. The experiments are in good agreement with numerical simulations, confirming high process flexibility in terms of peak reflectivity and wavelength selection. MHCGs have hitherto been regarded as mirrors enabling high reflection of selected light polarization. With this work, we show that thoughtfully designed MHCG yields high reflectivity for both orthogonal polarizations simultaneously. Our experiment demonstrates that MHCGs are promising candidates to replace conventional mirrors like distributed Bragg reflectors to realize resonator based optical and optoelectronic devices such as resonant cavity enhanced light emitting diodes and resonant cavity enhanced photodetectors in the mid-infrared spectral region, for which epitaxial growth of distributed Bragg reflectors is challenging.
KW  - monolithic grating
KW  - high contrast
KW  - mid-infrared wavelength applications
KW  - epitaxial structures
KW  - GaSb/AlAsSb
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-350346
VL  - 31
IS  - 10
ER  - 
TY  - JOUR
A1  - Winkler, Karol
A1  - Fischer, Julian
A1  - Schade, Anne
A1  - Amthor, Matthias
A1  - Dall, Robert
A1  - Geßler, Jonas
A1  - Emmerling, Monika
A1  - Ostrovskaya, Elena A.
A1  - Kamp, Martin
A1  - Schneider, Christian
A1  - Höfling, Sven
T1  - A polariton condensate in a photonic crystal potential landscape
JF  - New Journal of Physics
N2  - The possibility of investigating macroscopic coherent quantum states in polariton condensates and of engineering polariton landscapes in semiconductors has triggered interest in using polaritonic systems to simulate complex many-body phenomena. However, advanced experiments require superior trapping techniques that allow for the engineering of periodic and arbitrary potentials with strong on-site localization, clean condensate formation, and nearest-neighbor coupling. Here we establish a technology that meets these demands and enables strong, potentially tunable trapping without affecting the favorable polariton characteristics. The traps are based on a locally elongated microcavity which can be formed by standard lithography. We observe polariton condensation with non-resonant pumping in single traps and photonic crystal square lattice arrays. In the latter structures, we observe pronounced energy bands, complete band gaps, and spontaneous condensation at the M-point of the Brillouin zone.
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125050
VL  - 17
ER  -