Frequency stabilization of a semiconductor laser using the Rb saturated absorption spectroscopy

Abstract

ABSTRACT We report on the stabilization of a semiconductor laser’s frequency, using Rb absorption lines. In order to improve overall frequency stability within our system, we adjusted the setup used in Rb- saturated absorption spectroscopy, and optimized modulation parameters such as modulation - frequency and -width, to more accurately detect the error signal. When we stabilized laser frequency using a Doppler-free absorption line of Rb atoms, a time-constant of 0.01sec, and a modulation frequency of 7.77kHz, relative optical frequency stability of 2.12×10 -12 (2, ) 5.88×10 -11 was achieved, in averaging time for 0.04s 65s. Keywords : semiconductor laser, frequency stabilization, Rb absorption line, saturated absorption spectroscopy 1. INTRODUCTION Because of the inherent difficulty of maintaining the stability of semiconductor lasers’ oscillation frequencies, if either their temperatures or bias current are altered, during experiments employing them as light sources for optical frequency-, or phase-based systems, such as laser interferometers, they are the subject of countless reports