Nonlinear infrared spectrograph with 1 cm–1 resolution

A theoretical and experimental investigation was made of the possibility of constructing a nonlinear proustite spectrograph for the λ = 10μ range in which the infrared absorption spectrum would be obtained as a result of dispersion of the phase-matching angle in the conversion of the infrared frequency to the visible or near infrared range. Panoramic and scanning spectrograph systems were considered. It was found that a considerable improvement in the spectral characteristics should result from the use of the interaction characterized by a large angle between the pump and signal wave vectors. The dispersion and resolving power were determined for conversion of CO₂ laser radiation in proustite pumped with a YAG laser.