Noncollinear difference frequency mixing of dye laser and Nd:YAG second har
monic (fundamental) radiation from a commercial laser system is employed fo
r the generation of 2.7-5.3 mu m (1.6-1.7 mu m) radiations in a flux-grown
KTiOAsO4 crystal. The generated radiation is used to scan the methane absor
ption in the fundamental (upsilon(3)) and its first overtone (2 upsilon(3))
band at pressure 90 torr in a laboratory made single pass gas cell of leng
th 33 cm.