Abstract

Absorptive loss in the resonator of a multimode laser can be measured with high sensitivity provided that (i) the spectral width of the absorption is much narrower than the emission band, (ii) the duration of unperturbed generation of light in the individual modes is long, and (iii) the modes remain uncoupled. Ti: Sapphire has a gain band that extends from 700nm through 1µm.^[1] A cw laser with high-quality resonator shows typical 1.8% loss per round trip, and a long time of light generation ensues. An estimate based on observed data but neglecting mode coupling gives 100s.

© 1992 IQEC