This paper presents the phenomenology of different approaches to the frequency-shifting (upconversion) of infrared radiation into the visible and discusses the practical aspects of designing systems to up-convert IR images. The recently discovered process of upconverting infrared radiation into the visible or the ultraviolet using two-photon-pumped alkali-metal vapors and the more familiar method of frequency-mixing using single-photon-pumped nonlinear crystals are described and compared. In addition to these coherent processes, the use of quantum-counter action in certain crystals to convert an IR photon into a visible photon by an incoherent process is discussed. The important performance parameters of an IR imaging system are briefly discussed and the considerations and constraints involved in the design of coherent and incoherent image upconverter systems are presented. Using this background, practical system designs are developed for both active and passive imaging. The expected performances of these systems are compared with those of IR imaging systems based on direct-detection of IR photons with semiconductor detectors.
Infrared Imaging Using Nonlinear Optical Upconversion
Advances in Laser Engineering I ; 1977 ; San Diego,United States
Proc. SPIE ; 0122
1977-10-20
Conference paper
Electronic Resource
English