Bounce Laser Research Articles

1.2 MW peak power, all-solid-state picosecond laser with a microchip laser seed and a high gain single-passing bounce geometry amplifier

A semiconductor saturable absorber mirror (SESAM) based passively Q-switched microchip Nd:YVO4 seed laser with pulse duration of 90ps at repetition rate of 100kHz is amplified by single-passing a Nd:YVO4 bounce amplifier with varying seed input power from 20µW to 10mW. The liquid pure metal greasy thermally conductive material is used to replace the traditional thin indium foil as the thermal contact material for better heat load transfer of the Nd:YVO4 bounce amplifier. Temperature distribution at the pump surface is measured by an infrared imager to compare with the numerically simulated results. A highest single-passing output power of 11.3W is obtained for 10mW averaged seed power, achieving a pulse peak power of ~1.25MW and pulse energy of ~113µJ. The beam quality is well preserved with M2 ≤1.25. The simple configuration of this bounce laser amplifier made the system flexible, robust and cost-effective, showing attractive potential for further applications.

Broadband terahertz light source pumped by a 1 μm picosecond laser

We obtained a frequency tunable, low-coherence, picosecond, terahertz (THz) output with a high repetition rate from a picosecond Nd:YVO4 bounce laser in combination with tandem periodically poled stoichiometric lithium tantalate and 4′-dimethylamino-N-methyl-4-stilbazolium tosylate crystals. The frequency of the THz output was tunable in the range 2.1–7.1 THz with a linewidth of ~3.5 THz at 2.2 THz. The THz output had a maximum peak power of ~180 mW and an average power of ~0.65 μW at 3.9 THz. This system has the potential to realize ultra-high speed, THz coherence tomography.

Influence of energy transfer upconversion on thermal lens of Nd:YVO_4 bounce laser amplifier

Detrimental thermal effects affecting optical performances of a Nd:YVO4 bounce laser amplifier are investigated numerically under small-signal gain conditions. Thermally induced lens is stronger due to the increase of the fractional thermal loading with the pump irradiance, which is caused by the Auger energy-transfer upconversion (ETU). At a pump power of 100 W, the focal length of the thermal lens (TL) is comparable to the length of the laser crystal and is shorter than without Auger ETU by a factor of 3 and 2.5 in the bounce plane and, respectively, in the plane orthogonal to bounce. This deleterious influence of Auger ETU on the TL of the bounce laser amplifier can be alleviated by the increase of the pump spot area and by the mismatch between the diode pump spectrum and the absorption band of the crystal.

High efficiency 1341 nm Nd:GdVO4 bounce laser in-band pumped at 879 nm

A high-efficiency Nd:GdVO4 bounce laser in-band pumped at 879 nm is demonstrated for the first time. From a side-pumped Nd:GdVO4 crystal, 8.2 W output was obtained with 18.5 W absorbed pump power. Corresponding slope efficiency with respect to the absorbed pump power was 51.4%, and the beam quality factor M2 is 1.13 and 1.15 for tangential direction and sagittal direction, respectively. Effects of crystal’s doping concentration and temperature on laser power and conversion efficiency were also investigated.

Dual-frequency picosecond optical parametric generator pumped by a Nd-doped vanadate bounce laser

Dual-frequency MHz-repetition 1.5-μm optical parametric generation is demonstrated from a tandem system pumped by a picosecond Nd:YVO₄ bounce laser. An average power of 1.0 W is obtained over the range 1571-1630 nm, corresponding to an optical-optical conversion efficiency and slope efficiency of 16% and 23%, respectively. Terahertz-wave with a frequency of 3.2 THz is also generated from the system in combination with an organic nonlinear DAST crystal.

1.3-µm passive Q-switching of a Nd-doped mixed vanadate bounce laser in combination with a V:YAG saturable absorber

6.5-W, 1.3-µm passively Q-switched output was demonstrated from a side-pumped Nd-doped Gd0.6Y0.4VO4 bounce laser in combination with a V:YAG saturable-absorber crystal. Experimental output powers of 6.5 W and 6 W were measured at a maximum pump level in multi- and TEM00-mode operations, corresponding to optical-to-optical efficiencies of 17.5% and 16.2%, respectively.

Passive Q-switching of a diode-side-pumped Nd doped 1.3m ceramic YAG bounce laser

Abstract High power passive Q-switching of a diode-side-pumped Nd:YAG ceramic bounce laser at 1.3 μm is demonstrated. The laser operates from 18 to 114 kHz pulse repetition frequency, producing pulses of 55–140 ns duration. Average output power of 5.8 W was obtained from 52 W of pump power. Five Watts of high beam quality output was also achieved in an asymmetric cavity geometry.

Passive Q-switching of a diode-side-pumped Nd-doped mixed gadolinium yttrium vanadate bounce laser

High power passive Q-switching was achieved with a pulse width of 18–32 ns by using a diode-side-pumped Nd:Gd0.6Y0.4VO4 bounce amplifier. An average output power of > 8 W was obtained at a pump power of 39 W. The peak power of the Q-switched output was adjusted within 1.9–5.2 kW by changing the Nd concentration. The mixed vanadates showed significantly higher Q-switching performances in comparison with pure Nd:GdVO4.

Thermal-lens measurement in a side-pumped 1.3 μm Nd:YVO4 bounce laser

We investigated thermal-lensing effects in a side-pumped 1.3μm Nd:YVO4 slab laser amplifier having a bounce geometry. The thermal-lens power during 1.3μm laser action was 1.3-times larger than that without laser action. Excited-state absorption is the main cause for increased heat loading during laser operation. The heat-loading formula in end-pumped 1.3μm vanadate lasers having low Nd doping can be extended to account for heat generation in diode-side-pumped vanadate bounce lasers having high Nd doping.

Direct generation of high power Laguerre–Gaussian output from a diode-pumped Nd:YVO_4 1.3-μm bounce laser

We demonstrate direct production of a high power Laguerre-Gaussian mode from a diode-pumped Nd:YVO(4) 1.3-mum bounce amplifier with an asymmetric cavity configuration. A maximum LG output of 7.7 W is obtained.

High power scaling of a passively modelocked laser oscillator in a bounce geometry

In this paper we present the first operation and power scaling of a modelocked Nd:YVO4 bounce laser oscillator at 1064 nm. We obtain up to 16.7 W of average output power from 38 W of pump power, in a continuous-wave modelocked pulse train with 30 ps pulses at a repetition rate of 78 MHz. We then use a Master Oscillator Power Amplifier (MOPA) configuration utilising another bounce amplifier, to achieve 60 W of modelocked output power.

High repetition rate Q-switching performance in transversely diode-pumped Nd doped mixed gadolinium yttrium vanadate bounce laser

Up to 650kHz high repetition active Q-switching was achieved with a pulse-width of <40ns by using a diode-side-pumped Nd:Gd(x)Y(1-x)VO(4) bounce amplifier. An average output power of 17.5W was obtained at a pump power of 41W. The pulse repetition frequency range of the stable Q-switching operation was adjusted without any loss of the average output power by changing the Gd:Y mixture ratio.

High-power TEM00 grazing-incidence Nd:YVO4 oscillators in single and multiple bounce configurations

We describe single and multiple grazing incidence bounce laser configurations and present results of scaling a diode-pumped Nd:YVO4 amplifier to higher powers than previously demonstrated using these schemes. In a Nd:YVO4 slab amplifier laser employing a single total internal reflection bounce configuration 50.3 W of multimode and 46.2 W of TEM00 output power is demonstrated. This is the highest power demonstration to our knowledge of the grazing incidence Nd:YVO4 laser geometry. We further describe the design of novel multiple bounce geometries, in which the laser mode can take more than one total internal reflection path through the amplifier, and show it can offer advantages especially in terms of spatial quality. A demonstration of a double bounce laser oscillator configuration shows high power 41 W of TEM00 output power with high conversion efficiency but superior spatial beam quality compared to the TEM00 single bounce laser oscillator.