High-resolution Resonance Bragg-scattering spectroscopy of an atomic transition from a population difference grating in a vapor cell

TL;DR

This paper introduces a high-resolution resonance Bragg-scattering spectroscopy technique using a population difference grating in a vapor cell, achieving high signal-to-noise ratio and sub-natural linewidth for precise optical frequency measurements.

Contribution

It presents a novel RBS spectroscopy method based on a PDG formed by a standing-wave pump in thermal rubidium vapor, with theoretical explanation and experimental validation.

Findings

High S/N ratio in RBS spectrum

Sub-natural linewidth achieved

Effective modulation of atomic population distribution

Abstract

The laser spectroscopy with a narrow linewidth and high signal to noise ratio (S/N) is very important in the precise measurement of optical frequencies. Here, we present a novel high-resolution backward resonance Bragg-scattering (RBS) spectroscopy from a population difference grating (PDG). The PDG is formed by a standing-wave (SW) pump field in thermal 87Rb vapor, which periodically modulates the space population distribution of two levels in the 87Rb D1 line. A probe beam, having the identical frequency and the orthogonal polarization with the SW pump field, is Bragg-scattered by the PDG. Such Bragg-scattered light becomes stronger at an atomic resonance transition, which forms the RBS spectrum with a high S/N and sub-natural linewidth. Using the scheme of the coherent superposition of the individual Rayleigh-scattered light emitted from the atomic dipole oscillators on the PDG, the experimentally observed RBS spectroscopy is theoretically explained.