Compact high-pulse-energy passively Q-switched Nd:YLF laser with an ultra-low-magnification unstable resonator: application for efficient optical parametric oscillator

Abstract

We exploit an ultra-low-magnification unstable resonator to develop a high-pulse-energy side-pumped passively Q-switched Nd:YLF/Cr⁴⁺:YAG laser with improving beam quality. A wedged laser crystal is employed in the cavity to control the emissions at 1047 nm and 1053 nm independently through the cavity alignment. The pulse energies at 1047 nm and 1053 nm are found to be 19 mJ and 23 mJ, respectively. The peak powers for both wavelengths are higher than 2 MW. Furthermore, the developed Nd:YLF lasers are employed to pump a monolithic optical parametric oscillator for confirming the applicability in nonlinear wavelength conversions.

Nd:YLF laser at cryogenic temperature with orthogonally polarized simultaneous emission at 1047 nm and 1053 nm

“…However, due to the large difference of the stimulated emission cross section between the 1047-nm and 1053-nm emissions at room temperature [9][10][11], it is a critical issue to balance the gains for achieving the orthogonally-polarized simultaneous emission with equal output powers for two wavelengths. In earlier works [12,13], a wedged acut Nd:YLF crystal together with its birefringence property was employed to select the emission at 1047 nm and 1053 nm by separating the resonant path in the cavity. Even though this approach could be used to obtain the simultaneous emission by aligning the optical path just between two resonant paths, the total output power certainly suffered considerable losses arising from the misalignment for balancing the gains.…”

Investigating the Threshold Conditions of Air Breakdown with Mode-Locked Q-Switched Laser Pulses, and the Temporal Dynamics of Induced Plasma with Self-Scattering Phenomenon

“…The Nd:YAG rod and the flash lamp were placed inside a pumping enclosure consisting of reflectors coated with silver on the inside surface to improve the pump efficiency. The laser resonator was designed as a convex-concave cavity to enlarge the laser mode volume for achieving high pulse-energy output with good beam quality [32]. The radius of curvature of the convex front mirror was −500 mm, and the surface was coated for high reflection (HR, R > 99.9%) at 1064 nm.…”

“…A Cr 4+ :YAG crystal with initial transmittance of 35% was employed as the saturable absorbe The effective cavity length was chosen to be 90 mm. With a weak thermal lensing effect the laser was operated in a stable region [32,34]. The output pulse energy was able to b stabilized around 21 mJ with one-sigma stability of 1% under continuous-firing operation at a repetition rate of 0.2 Hz after warm-up.…”

“…In this work, we utilized the lamp-pumped high-energy Q-switched Nd:YAG laser to explore the threshold conditions of the air breakdown. Based on the designed convexconcave resonator for good beam quality [32] and wedged gain crystal to avoid etalon effect for simultaneously mode-locking [33,34]. The mode-locking modulation may have suffered from the instabilities caused by the inhomogeneous thermal loading and cavity misalignment [35,36].…”

A millijouleα-BaTeMo2O9Raman laser driven by a diode-pumped Nd:YLF laser

“…The Nd:YLF crystal is another excellent gain medium with longer fluorescence lifetime and its dn/dt coefficient is negative. The better energy storage capability and weaker thermal lensing effects make the Nd:YLF crystal suitable for high pulse energy laser operation [14][15][16][17].…”