Intracavity absorption spectroscopy with a Nd^3+-doped fiber laser

Abstract

A broadband Nd(3+)-doped fiber laser has been operated in an external cavity by pumping with an Ar(+)-ion laser. The emission spectrum of the fiber laser shows high sensitivity to intracavity absorption. The equivalent absorber path length is 15 km; with a loss-reduced setup that includes pumping by a diode laser this path length is 150 km. The spectrum of atmospheric absorption in the range from 1.065 to 1.145 microm has been recorded by stepwise tuning of the 0.3-nm-wide laser emission band by an intracavity prism.