75%-efficiency blue generation from an intracavity PPKTP frequency doubler

Rodolphe Le Targat (1) , Jean-Jacques Zondy (1) , Pierre Lemonde (1)

1 SYRTE - Systèmes de Référence Temps Espace

We report on a high-efficiency 461 nm blue light conversion from an external cavity-enhanced second-harmonic generation of a 922 nm diode laser with a quasi-phase-matched KTP crystal (PPKTP). By choosing a long crystal (LC=20 mm) and twice looser focusing (w0=43μm) than the öptimal\" one, thermal lensing effects due to the blue power absorption are minimized while still maintaining near-optimal conversion efficiency. A stable blue power of 234 mW with a net conversion efficiency of eta=75% at an input mode-matched power of 310 mW is obtained. The intra-cavity measurements of the conversion efficiency and temperature tuning bandwidth yield an accurate value d33(461 nm)=15 pm/V for KTP and provide a stringent validation of some recently published linear and thermo-optic dispersion data of KTP.

Mots clés: Second harmonic generation; PPKTP; strontium; thermal effects

Domaines: Optique [physics.optics]

Rodolphe Le Targat, Jean-Jacques Zondy, Pierre Lemonde. 75%-efficiency blue generation from an intracavity PPKTP frequency doubler. Optics Communications, 2005, 247, pp.471. ⟨10.1016/j.optcom.2004.11.081⟩. ⟨hal-00002488⟩