Electromagnetic modeling of multi-wavelength QWIP optical coupling structures

Quantum-well infrared photodetector (QWIP) materials can be engineered to be optically absorbing over a wide range of wavelengths. This enables multi-band focal plane arrays to be realized. However, some of this flexibility is lost due to the required optical coupling structure that converts normally incident light to horizontal propagation to allow absorption. Such coupling structures are typically strongly wavelength-dependent and must be tuned to the waveband of interest. In this study, we perform electromagnetic simulations to understand and optimize optical coupling structures for multi-band QWIPs.