The Optimization Of Optical Antenna For Quantum Well Infrared Photodetectors

As a hot area of research for infrared detector, Quantum Well Infrared photo-detector technology shows more advantages in product rate than conventional infrared photo-detector, since it can fabricate an imaging system with large area, lower power, lower cost, high uniformity and high sensitivity focal plane array. By control the composition of material and depth of well and barrier height, the detected wavelength can be obtained. The transition within the same conduction band between different sub-bands rely on the direction of light polarization field, so it becomes one important directions of QWIP to couple more incident light into QW(quantum well).Since the emerging of QWIP, all kinds of coupling method appeared. In this paper, we focus on the two-dimensional(2D) optical antenna. It can increase the rate of light absorption by coupling far field light into near field optical mode. The optical antenna is a golden film with nanohole array, surface plasmon resonate wavelength is highly dependent on the periodicity of nanohole array. Simulation was carried out using FDTD solutions software, because the feature size of the optical antenna and wavelength have the same order of magnitude. By tuning structure parameters of 2D optical antenna, we achieve the best coupling efficiency for detecting wavelength of 8.5um.