Generation of 656 nm coherent red-light by frequency-doubled Nd:YLiF₄/β-BaB₂O₄ laser for a compact silver atoms optical clock

¹ LISV, University of Versailles, 78035 Versailles, France
² CNRS/Insu LATMOS-IPSL, University of Versailles, 78280 Guyancourt, France
³ LNE-INM/CNAM, 93210 Saint-Denis, France

^⋆ Correspondence: suat.topsu@uvsq.fr

Received: 26 March 2012
Accepted: 26 March 2012

Abstract

We describe an efficient continuous-wave diode-pumped Nd:YLiF₄ laser oscillating on the σ-polarized ⁴F_3/2-⁴I_13/2 transition at λ_ω = 1312 nm. With a simple linear cavity laser, we reached an intracavity power of 310 W at λ = 1312 nm for 16 W of absorbed pump power (λ_p ~ 806 nm). A 0.25 W of tunable radiation (λ_2ω = 656−658 nm) was obtained by intracavity second-harmonic generation (SHG) with a 5 × 5 × 7 mm³β-BaB₂O₄ crystal. Up to 10 mW of tunable single-frequency operation was observed using a 200 μm thin fused silica intracavity solid etalon. The optimal waist for a maximum conversion efficiency has been calculated theoretically using Boyd and Kleiman model. For the 1312–656 nm SHG, we found a walk-off parameter B = 8.99 and an optimal waist of 25 μm. Comparing to the experimental measurement of the optimal waist, we found a relative discrepancy of 2.84 × 10^-2. This laser is dedicated to the spectroscopic study of silver atoms trapped in a buffer-gas-free paraffin coated Pyrex cell that will be used in a compact atomic optical clock.