Photonic Crystal Quantum Well Infrared Photodetectors
Due to quantum mechanical selection rules QWIPs are only sensitive to light with the electric field
polarized perpendicular to the surface and therefore cannot detect surface incident light.
One of the main application fields though is thermal imaging, which calls for surface-sensitive
photodetectors. In our group we fabricate GaAs/AlGaAs QWIPs as 2D photonic crystals (PhCs).
They can diffract incident light and make these detectors sensitive to surface incident light -
a necessity for the realization of pixel arrays. As the in-coupling is highly resonant it is
possible improve signal-to-noise performance and rise operating temperature. Additionally the
unique symmetry/polarization properties of PhCs are believed to increase functionality of the devices.
SEM image of a photonic crystal QWIP device