Microwave Light Modulation by an Optically PumpedRb87Vapor

Abstract
We have observed appreciable light modulation at the 6.835-GHz hfs transition frequency of optically pumped Rb87 vapor. The frequency separation between the levels involved in the transition exceeded the total spectral width of the initial lamp profile. These observations indicate that persistent doubts as to the feasibility of a transmission-light-modulation experiment under such conditions are groundless.