Abstract
A novel method of thermal imaging based on the up-conversion of infrared radiation in nonlinear optical crystals is analyzed. An equation is derived giving the temperature resolution in terms of the pump laser energy Ep. For a proustite–ruby system based on the 8–13-μ band, a temperature resolution of better than 1 °C is predicted when the number of resolvable spots is 100 × 100 and Ep = 10 J. Numerical results are also provided for eighteen possible systems having different combinations of pump laser (neodymium or ruby), infrared band (3–5 μ or 8–13 μ), nonlinear crystal (Ag3AsS3, AgGas2, ZnGeP2, or LiNbO3), and imaging photocathode [S-1,S-20, GaAs/(Cs,O), or In(As,P)/(Cs,O)].