Single-crystal sum-frequency-generating optical parametric oscillator

Abstract

Cataloged from PDF version of article.We report a synchronously pumped optical parametric oscillator that generates the sum frequency of the pump and the signal wavelengths. A single KTiOPO4 (KTP) crystal is used for both parametric generation and sum-frequency generation in which these two processes are simultaneously phase matched for the same direction of propagation. The parametric oscillator, pumped by a femtosecond Ti:sapphire laser at a wavelength of 827 nm, generates a blue output beam at 487 nm with 43% power-conversion efficiency. The polarization geometry of simultaneous phase matching requires rotation of the pump polarization before the cavity. Adjusting the group delay between the two orthogonally polarized pump components to compensate for the group-velocity mismatch in the KTP crystal increases the photon-conversion efficiency more than threefold. Angle tuning in conjunction with pump wavelength tuning provides output: tunability in the 484-512-nm range. A planewave model that takes group-velocity mismatch into account is in good agreement with our experimental results. (C) 1999 Optical Society of America [S0740-3224(99)01309-0]

Nanosecond sum-frequency generating optical parametric oscillator using simultaneous phase matching

“…This technique has been demonstrated to provide efficient frequency conversion to wavelengths that cannot be reached via a single nonlinear process [7][8][9][10][11][12][13][14][15]. In particular, both femtosecond and continuous-wave Ti:sapphire laser beams were upconverted to visible wavelengths by combining sum-frequency generation (SFG) [10,11] or second-harmonic generation [11,13,14] with optical parametric oscillation.…”

Highly Efficient Wavelength Conversion of Q-Switched Nd:YAG Lasers Into a Red Wavelength

“…Digital Object Identifier 10.1109/JQE.2006.876711 Combining two steps of frequency conversion within the same nonlinear crystal using simultaneous phase matching facilitates efficient frequency conversion to wavelengths that cannot be reached via a single nonlinear process [17]- [26]. In particular, both femtosecond and cw Ti:sapphire laser beams have been upconverted to visible wavelengths by combining sum-frequency generation (SFG) [20], [21] or second-harmonic generation [21], [23], [24] with optical parametric oscillation. We recently reported a sum-frequency generating OPO (SF-OPO) that extends this approach to the nanosecond regime [26].…”

Simultaneous phase matching of optical parametric oscillation and second-harmonic generation in aperiodically poled lithium niobate

“…3 In second-order nonlinear crystals, the phase-matching condition is most commonly satisfied either by birefringent phase matching (BPM), in which the natural birefringence of the crystal is utilized, 30 or by quasi-phase matching (QPM), in which periodic domain reversals fabricated into the crystal lead to a grating momentum that cancels the natural phase mismatch. [31][32][33] Both BPM [1][2][3][4] and QPM [8][9][10][11][12][13] have been used for simultaneous phase matching of two separate processes within the same nonlinear crystal. When the BPM method is used, the two phase-matching conditions are simultaneously satisfied for a set of wavelengths and polarization directions, a particular direction of propagation, and a particular temperature.…”

“…This is the result of a coincidental crossing of the phase-matching curves of the two processes. [1][2][3][4] In the case of QPM, the phase-mismatch term of one process is canceled by the fundamental Fourier component of the grating momentum; the grating period is chosen to this end. The phase-mismatch term of the second process has to coincide with one of the harmonics of the grating momentum for simultaneous phase matching to occur.…”