2. Photon Management

Various methods of photon management used to enhance the detector response are systematized and analyzed. The proposed classification points out to some possible novel approaches to photon management optimization, as well as to certain methods that until now were used only in other fields of optical engineering. Various light trapping methods in the far or in the near field are described. The analyzed structures include those for incident optical flux increase (imaging and nonimaging concentrators – e.g. refractive and diffractive lenses, reflective structures, etc.), antireflection structure (interference films and diffractive subwavelength reliefs), light trapping structures for optical path increase and radiative lifetime increase through photon recycling (total internal reflection reliefs, high reflection films and structures, resonant cavity enhancement, radiative shields and photonic crystal enhancement. The possibility of the use of plasmonics in infrared detector enhancement is considered since it ensures the possibility of electromagnetic field concentration in subwavelength domains. Different novel structures like nanoantennas, negative index metamaterials, etc. are considered as means to improve light management in a photo detector. Although described primarily from the point of view of semiconductor infrared detectors, a majority of these methods can be applied to other devices, most notably solar cells.