Singly resonant cw OPO with simple wavelength tuning

Markku Vainio,Lauri Halonen,Stefan Persijn,Jari Peltola,Frans J M Harren

doi:10.1364/oe.16.011141

Abstract

A singly resonant continuous-wave optical parametric oscillator (cw OPO) is described. The OPO contains no intracavity etalon, which makes its wavelength tuning simple and straightforward, including only temperature tuning of the nonlinear crystal and wavelength tuning of the pump laser. The OPO provides watt-level output in the mid-infrared region and operates reliably without mode hops for several hours.

Highlights

Continuous-wave optical parametric oscillators have become important spectroscopic tools in the mid-infrared region, where the availability of tunable laser sources is otherwise limited
We present the first demonstration of a cw singly resonant OPO that reliably operates in a single longitudinal mode without the need for an intracavity etalon
We have shown that it is possible to obtain reliable single-mode operation of a singly resonant continuous-wave optical parametric oscillator (cw OPO) without any etalon or other frequency selective intracavity elements

Summary

Introduction

Continuous-wave optical parametric oscillators (cw OPOs) have become important spectroscopic tools in the mid-infrared region, where the availability of tunable laser sources is otherwise limited. Resonant OPOs are of particular interest because of their large output powers of up to several watts [1,2]. In the 3-μm-band OPOs, the most commonly used nonlinear crystal is MgO-doped, periodically poled lithium niobate (MgO:PPLN). Coarse wavelength tuning of several hundred cm-1 can be attained by selecting appropriate crystal poling period and by tuning the crystal temperature for the desired phase-matching wavelength. Mode-hop free fine tuning, is more difficult to obtain over a frequency range that would be large enough for practical applications. The most promising method is pump-tuning, in which the OPO signal wavelength is kept fixed while the pump laser is tuned. Recent advances with the widely tunable high-power pump lasers have made it possible to obtain mode-hop free idler tuning of more than 100 GHz [1,3]

Methods

Findings

Discussion

Conclusion