Micrometric Atomic Layer Saturated Absorption Spectroscopy for Studying Cesium 6S1/2 → 7P3/2 Transitions at 456 nm

Features of Doppler-free resonances formed during scanning of Cs-atom 6S_1/2 → 7P_3/2 transitions at 456 nm in a micrometer cell are presented. The saturated absorption technique in a cell with a thickness of L = 40 μm was used. The oscillator strength of these transitions is 60 times weaker than for Cs 6S_1/2 → 6P_3/2 transitions at 852 nm. The Doppler-free resonances have a spectral line width of <20 MHz, which is 38 times smaller than the Doppler line width of 750 MHz at 120°C. These narrow resonances are of interest for both high-resolution spectroscopy and instrumentation, in particular, the creation of compact frequency references in the blue region.