High-stability single-frequency green laser with a wedge Nd:YVO4 as a polarizing beam splitter

Continuous-wave single-frequency 532 nm laser source emitting 130 W into the fundamental transversal mode

“…In some setups, the optical resonator was realized by the primary laser resonator itself. But such intracavity doubling schemes were limited by instabilities (e.g., [11,12]). Therefore, we decided to place the nonlinear crystal within an external optical resonator.…”

Broadband tunable single-frequency Nd:YVO4/LBO green laser with high output power

“…In this case, the depletion of the main mode during frequency upconversion will unavoidably increase the possibility of the oscillation of other unexpected polarization modes. For solving the problem, in our design an end face of the laser crystal (Nd:YVO 4 ) is cut in a wedge shape with a suitable angle (the angle depends on the pump power of the laser; see [8] for details) to serve as a polarizing beam splitter for suppressing the oscillation of unexpected polarization modes and enhancing the superiority of the main polarization mode in the mode competition. According to [8], for a pump power of 47 W used in our experiment, the calculated minimum wedge angle for suppressing completely the σ-polarization laser equals 1.2°, so we cut an end facet of the Nd:YVO 4 crystal in a wedge shape of α 1.5°with respect to the c axis of the crystal and made its front facet parallel to the c axis, which is enough to suppress the oscillation of the unexpected σ-polarization mode and enhance the superiority of the π-polarization mode in the mode competition.…”

“…1) of the laser to resonate in the resonator by adjusting its incident direction on the wedge-shaped end facet of the laser crystal and to suppress those unexpected modes (dashed line shown in Fig. 1) [8]. At the same time, the wedgeshaped end facet is also used for eliminating the influence of the etalon effect resulting from the two plano-plano faces of crystal on the frequencytuning characteristics of the laser [25].…”

“…For example, for spectroscopy applications of molecular iodine with the transition of 532.245 nm and I 2 -stabilized laser systems, singlefrequency green radiation around 532 nm with high output power above several watts and a significant tuning range over 10 GHz are required. High-power single-frequency green lasers using the ring cavity geometry were reported by several groups [6][7][8].…”

240-GHz continuously frequency-tuneable Nd:YVO_4/LBO laser with two intra-cavity locked etalons

“…Single-frequency ring Nd:YVO 4 lasers with intra-cavity frequency doubling by nonlinear crystals (NC) are widely used in a variety of applications requiring powerful and stable green radiation with long coherence length. Because of a relatively narrow spectral gain profile of their active medium, these lasers are often considered "single-wave", even though the gain bandwidth in Nd:YVO 4 (257 GHz [1,2]) is as much as 4-5 orders of magnitude wider than the typical fundamental radiation line width of a single-frequency Nd:YVO 4 laser without frequency stabilisation (~1.2-25 MHz [3][4][5]). In this relation, it is quite natural to consider a single-frequency Nd:YVO 4 laser as a tuneable one, capable of relatively wide frequency tuning within tens and hundreds of GHz.…”