Continuous wave tunable laser from 616 nm to 637 nm based on a compact sum frequency generation setup

Ruizhe Gu, Dia Darwich, Germain Guiraud, Mathieu Chauvet, Coline Mahob, Christof Janssen, Giorgio Santarelli, and Adèle Hilico

Abstract

We report on a compact sum frequency generation (SFG) setup generating continuously tunable single-frequency visible radiation from 616 nm to 637 nm, starting from two tunable laser sources at 1 µm and 1.5 µm. We compare two types of crystals: periodically poled lithium niobate (PPLN) and periodically poled magnesium oxide-doped lithium niobate (PPMgOLN), both custom-made such that the tunability range is achieved via temperature control only. We achieve a Watt level of power over the entire tunability range in PPMgOLN, with a mode profile enabling 80% coupling efficiency in a single-mode fiber, limited by the IR sources' tunability, while keeping the system easy to operate.