Measurement of frequency sweep nonlinearity using atomic absorption spectroscopy

TL;DR

This paper presents a low-cost method using atomic absorption spectroscopy to measure and correct frequency sweep nonlinearity in laser systems, enabling precise real-time frequency monitoring.

Contribution

The authors introduce a novel, cost-effective technique that simultaneously measures optical frequency and path difference, improving accuracy in frequency sweep characterization.

Findings

Frequency sweep nonlinearity is approximately 7.68%.

Average frequency modulation rate is around 28.95 GHz/s.

Method agrees well with theoretical predictions.

Abstract

A low cost scheme to determine the frequency sweep nonlinearity using atomic saturated absorption spectroscopy is demonstrated. The frequency modulation rate is determined by directly measuring the interference fringe number and frequency gap between two atomic transition peaks of rubidium atom. Experimental results show that the frequency sweep nonlinearity is ~7.68%, with the average frequency modulation rate of ~28.95 GHz/s, which is in good agreement with theoretical expectation. With this method, the absolute optical frequency and optical path difference between two laser beams are simultaneously measured. This novel technique can be used for applications such as optical frequency sweep nonlinearity correction and real-time frequency monitor.