Beam quality improvement by controlling thermal lens spherical aberration in an end-pumped Nd:YVO₄laser

Abstract

We present for the first time, to the best of our knowledge, the influence of spherical aberration on the beam quality of a single-stage laser amplifier. We set up an amplifier with a special structure to measure the spherical aberration distribution in the cavity. The output power of the oscillator was controlled, and the pump power of the amplifier was adjusted to improve the beam quality. The results show that there is an optimal amplifier pump power, which maximizes the output laser beam quality. In the presented experiment, an optimal laser beam was achieved with an output power of 10.54 W and beam quality of Mx2=1.54, My2=1.39 for a pump power of 9.33 W, oscillator output power of 9.2 W, and a beam quality of Mx2=2.10, My2=2.03.

Research on temperature stability of multi-segmented Nd:YAG/Nd:GdVO4 crystals laser

“…For LD powers not exceeding 50W, thermoelectric coolers (TECs) can be used to precisely control the LD temperature. However, at high LD powers, the heat dissipation capability of TECs becomes inadequate for the precise temperature regulation required [9][10] . The second method entails selecting gain media with broad absorption spectra.…”

The effect of the pumping inhomogeneity factor on spherical aberration in a dynamic stability cavity

“…In 2016, Liu et al compared spherical aberration at different positions of crystal end faces in symmetric and asymmetric cavities [7]. In 2018, Yao et al put forward the spherical aberration effect on the beam quality of a single-stage laser amplifier, and gave the connection among a spherical aberration coefficient, the output power and wavefront phase distribution at a lower pump power [8]. In the same year, Wang et al used the Hartmann-Shack wavefront sensor to reconstruct the relevant wavefront information of an end-pumped Nd:YVO 4 crystal, which proves that beam quality is affected by the thermal focal length and spherical aberration [9].…”

Dynamic effects of temperature-dependent aberration factors on the beam quality of LD end-pumped lasers

“…16) The deterioration of the beam quality of a Gaussian beam by the quartic phase term can be analyzed by applying second-order intensity moments to the aberrated Gaussian beam. Using one transit through the lens, beam propagation factor M 2 after the lens can be expressed: 17,18)…”