Observation of Rb Two-Photon Absorption Directly Excited by an Erbium-Fiber-Laser-Based Optical Frequency Comb via Spectral Control

TL;DR

This paper reports the direct excitation of rubidium two-photon absorption using an erbium-fiber-laser-based optical frequency comb, with spectral control enhancing transition strength and resolution, advancing optical frequency standards.

Contribution

It introduces a spectral control method to enhance two-photon transition detection at fiber communication wavelengths, enabling potential high-stability optical clocks.

Findings

Resolved two-photon transition spectrum with clear lines

Enhanced second harmonic comb generation through spectral control

Potential for high-precision optical frequency standards at 1.5 μm

Abstract

We demonstrated the observation of Rb two-photon absorption directly excided by an optical frequency comb at fiber communication bands. A chain of comb spectral control is elaborately implemented to increase the power of the second harmonic optical frequency comb generation and the two-photon transition strength. A two-photon transition spectrum is obtained with clearly resolved transition lines. It provides a potential approach to realize the optical frequency comb or optical clock at ~1.5{\mu}m with high stability and accuracy.