Walk-off corrected KTP crystal for low pulse energy pumped optical parametric oscillation

Optical parametric oscillations based on multiple-layer-bonded walk-off-compensated KTiOPO<inf>4</inf> stacks

“…In such alignment, the PB-WOC composite shows NCPM properties with close-to-zero spatial walk-off and nearly N fold larger angular acceptance compared with the single crystal device, where N is an even number that represents the crystal number used in the composite [4]. It is worth mentioning that the PB-WOC composite still has the same wavelength bandwidth as a single bulk crystal because the Δk that is caused by wavelength mismatch will be the same sign for all the bonded KTP layers and therefore will be accumulated instead of compensated in the WOC composite.…”

“…In Ref. [4,6], QNCPM OPO and dual-wavelength QPM OPO have been demonstrated in 16-layer PB-WOC KTP stacks. In Ref.…”

“…To overcome the problem, a common method is to use one or more oppositely orientated crystal pairs to compensate the spatial walk-off [1][2][3]. This not only increases the beam overlap, but also increases the angular acceptance of the nonlinear process [3,4]. In principle, the shorter the single crystal length that is used, the better the beam overlap and the larger the angular acceptance that can be achieved.…”

Adhesive-free bond quasi-noncritical phase-matched and quasi-phase-matched optical parametric oscillations

“…In order to reduce the OPO threshold and increase its efficiency, a common method is using a walk-off compensated (WOC) KTP pair to replace the single KTP crystal, in which oppositely oriented KTP crystals can be arranged separately [5] or bonded together [6,8,9]. Although the output wavelengths of the later one cannot be tuned through the crystal polar angle (θ), it can have the following advantages [9]: 1. No complicated synchronous tuning setups are required as in the separated WOC geometry.…”

“…As a result, large-scale pump lasers with pulse energy at least above several millijoules are usually required [3,4]. In order to reduce the OPO threshold and increase its efficiency, a common method is using a walk-off compensated (WOC) KTP pair to replace the single KTP crystal, in which oppositely oriented KTP crystals can be arranged separately [5] or bonded together [6,8,9]. Although the output wavelengths of the later one cannot be tuned through the crystal polar angle (θ), it can have the following advantages [9]: 1.…”