High-power, continuous-wave, singly resonant, intracavity optical parametric oscillator

Abstract

A high-power continuous-wave optical parametric oscillator based on the nonlinear material KTiOAsO4 and pumped internal to a tunable Ti:sapphire laser is described. The use of the intracavity pumping approach has enabled operation of a singly resonant oscillator (SRO), resulting in the generation of as much as 1.46 W of infrared power in a 11.5-mm-long crystal. Amplitude-stable signal and idler outputs, each in excess of 500 mW, over the respective wavelength ranges of 1.11–1.20 and 2.44–2.86 μm have been extracted from the SRO. We demonstrate up to 90% down-conversion of the optimum Ti:sapphire output power to the SRO, confirming our recent theoretical predictions. The performance characteristics of the device demonstrate that practical, stable, and efficient operation of continuous-wave SROs at watt-level output power can be readily achieved in conventional birefringent materials by exploiting the intracavity pumping approach.

Practical Continuous-Wave Intracavity Optical Parametric Oscillators

“…In this final section we shall discuss the elimination of ICOPO relaxation oscillations by devising a system such that the upper-state and cavity photon lifetimes are comparable by the use of laser gain materials which exhibit very short upper-state lifetimes. The pioneering early cw-ICOPO work (Colville, Dunn et al 1997;Turnbull, Edwards et al 1997;Edwards, Turnbull et al 1998) was carried out using argon-ion pumped Titanium:Sapphire (Ti:S) lasers, and as such did not experience any problems with the transient instability which have plagued similar systems predicated upon Nd lasers. This is, of course, due to the short upper-state lifetime exhibited by Ti:S of ~3μs (approximately two orders of magnitude less than Nd:YAG) in addition to the longer cavity photon lifetimes resulting from the somewhat lengthier cavities used in these systems.…”

Multifunctional Optical Crystals for All-Solid-State Raman Lasers

“…KTA crystal has an orthorhombic structure with non-centro-symmetric point group C 2v (mm 2 ) and space group Pna2 1 (Z58). Due to the high nonlinear coefficient (d 33 = 16.2 pm/V) and high damage threshold (>300 MW/cm 2 ), KTA crystal has been used in optical parametric oscillators (OPOs) since the 1990s [111,112]. In 1996, Tu et al [113] proved that KTA is an excellent Raman medium with Raman gain coefficients of~2.5 cm/GW at 234 cm −1 and~0.6 cm/GW at 671 cm −1 , respectively, and corresponding Raman line widths of 5.8 and 19 cm −1 .…”

Femtosecond Laser Micromachining of Cladding Waveguides in KTiOAsO4 Crystal for Second‐Harmonic Generation

“…Potassium titanyl arsenate (KTiOAsO 4 , KTA), as a fascinating isomorphic nonlinear optical crystal, intrinsically possesses preferable effective nonlinear optical coefficients (i.e., d 31 and d 33 ), [ 1 ] extended optical transmission range up to 5.3 μm, [ 2 ] higher optical damage threshold at 1064 nm, and reduced optical absorption in comparison with potassium titanyl phosphate (KTiOPO 4 or KTP). [ 3,4 ] Benefiting from its outstanding nonlinear optical and Raman properties, [ 5,6 ] KTA exhibits intriguing performance in nonlinear optics, [ 3,7–9 ] Raman lasers, [ 10–12 ] electro‐optic Q ‐switched laser, [ 13 ] and so on. Numerous studies on the nonlinear optical properties of KTA at midinfrared (MIR) wavelengths have been demonstrated.…”