Pumped Slab Laser Research Articles

Quasi-Continuous Wave Pumped Slab Laser Based on Nd:CTGS Crystal

Quasi-Continuous Wave Pumped Slab Laser Based on Nd:CTGS Crystal

Design and simulation of locally enhanced microchannel heat sink for diode partially pumped slab laser

With the power level of diode-pumped solid-state laser (DPSSL) rising continuously, its thermal effect has become the main problem limiting the laser performance. In this paper, based on the heat distribution of diode partially end-pumped slab (Innoslab) laser, a shunt rectangular microchannel heat sink with locally enhanced heat dissipation is designed. Firstly, multi-stage parallel short channels are designed in the heat concentration area to enhance the solid-liquid heat exchange in this area, and the effects of structure and working conditions on its heat dissipation performance are investigated. Secondly, the copper layer is introduced into the end face of the low thermal conductivity crystal to form a high thermal conductivity path, which alleviates the heat accumulation inside the crystal. Under a certain condition, compared with the traditional liquid-cooled plate system, the maximum temperature of the laser crystal is reduced from 169.62 to 118.18 °C, the pressure drop is reduced by 66.75%, and the total mass of the system is reduced to 4.87% of the original system, which effectively improves the practical performance of the device.

Investigation on efficiency declines due to spectral overlap between LDAs pump and laser medium in high power double face pumped slab laser

Abstract In high power diode lasers, the input cooling water temperature would affect both output power and output spectrum. In double face pumped slab laser, the spectrum of two laser diode arrays (LDAs) must be optimized for efficiency reason. The spectrum mismatch of two LDAs would result in energy storing decline. In this work, thermal induced efficiency decline due to spectral overlap between high power LDAs and laser medium was investigated. A numerical model was developed to describe the energy storing variation with changing LDAs cooling water temperature and configuration (series/parallel connected). A confirmatory experiment was conducted using a double face pumped slab module. The experiment results show good agreements with simulations.

Conductively-cooled, high-energy, single-frequency diode pumped slab laser for space applications

A laser-diode-pumped high efficiency, high pulse energy and single-frequency oscillator and amplifier for potential space environment applications have been developed and demonstrated using conductively-cooled heat removal. A diode-pumped injection seeded single-frequency oscillator was achieved by using the resonance-detection technique in Q-Switching operation, and Nd: YAG zigzag slabs based on “pump on bounce” are used in power amplifier stage for high-efficiency pulse energy extraction. Output pulse energy of 800 mJ with 11 ns pulse duration is obtained at a repetition rate of 100 Hz, with a near 3× diffraction-limit beam and an optical-to-optical efficiency of 18%. The experimental result shows that the laser has compact structure, high efficiency, reliability, conductive cooling and can be used for space environments.

Thermal lens and beam properties in multiple longitudinally diode laser pumped Nd:YAG slab lasers

The focal length of the thermal lens and the beam quality factor (beam propagation factor) M/sup 2/ for a multiple longitudinally diode pumped slab laser is deduced for pump and output powers up to 16 and 4.5 W, respectively. Due to the geometry of the arrangement, a stronger thermal lens is observed in the plane with the larger pump spot radius as predicted by an analytical model for slab geometries. In addition, the second stable zone of an asymmetric resonator is found to be advantageous for improved beam properties at high output powers.

Determination of the thermal lens in solid-state lasers with stable cavities

A useful method to determine the thermal lens in a thermally loaded material inside a laser resonator under operation is presented. The laser beam emitted is focused with a lens placed exactly at the distance of its focal length behind the output mirror. For stable spherical resonators this focusing is not astigmatic even for an astigmatic cavity. This fact is used to experimentally determine the thermal lens including the beam quality factor (beam propagation factor) M/sup 2/ of the laser beam. Measurements are presented for an end-pumped rod and a longitudinally pumped slab laser serving as an example for an astigmatic cavity.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

High average powers diode pumped slab laser

The authors have developed and tested stackable microchannel cooled laser bar diode pump packages suitable for direct pumping of slab lasers at high duty factor. A stack of 41 diode packages gives a pump array of 13.5 cm/sup 2/ and produces a peak power of 4000 W and an average power of 1000 W for an average irradiance of 75 W/cm/sup 2/. A high average power, total internal reflection face pumped Nd:YAG laser using 80 diode packages has been constructed. Preliminary testing of the slab laser using a 20% subset of diode packages arranged to pump a 4 mm*4 mm*80 mm volume of the slab has been completed. Seventy watts average power is obtained at 2.5 kHz pulse repetition rates and 100 mu s pulse widths. >

Average power limits of diode-laser-pumped solid state lasers

We investigated the average power limits of diode laser pumped slab lasers and present design calculations for several laser configurations. In the laser designs, a number of diode lasers, each one of which is coupled to an optical fiber are employed to pump a solid state laser material in a zigzag slab or a disk geometry. The systems described here can produce multiple kilowatts of average output power with currently available diode lasers in a cost-effective manner.