Periodically Poled Lithium Niobate Crystal Research Articles

25-W, continuous-wave, 629-nm solid-state laser source

We report an efficient, high-power, cw, 629-nm laser source based on a diode-pumped Nd:YAG laser and a periodically poled lithium niobate (PPLN) frequency converter. This device integrates two separate frequency-conversion steps in a single crystal, taking advantage of the ability to fabricate PPLN with nearly arbitrary grating periods and phase-matching temperatures. This device uses a single PPLN crystal that has two grating regions in series. The first region quasi-phase matches a standard optical parametric oscillator process (1064nm?1540nm +3450nm), and the second region quasi-phase matches a sum-frequency process whereby the pump and the signal light make red light (1064nm+1540nm ?629nm). Using a four-mirror ring cavity, we were able to convert 21% of the 1064-nm pump to 629-nm output, yielding 2.5W of red output with 11.8W of input.

Second harmonic generation around 0.53 [micro sign]m of seeded Yb fibre system in periodically-poled lithium niobate

Fibre-integrated, seeded, high-power Yb-doped fibre amplifiers have been used in combination with periodically-poled lithium niobate crystals in simple experimental configurations to give second harmonic generation to the visible both in CW and pulsed formats with conversion efficiencies as high as 41% in compact configurations.