In addition, the effect of pump and gain medium properties on the optimal fundamental beam by taking into account thermal aberration are investigated.
In this paper, with the example of transversally pumped, high-power Nd YAG lasers, we show the importance of the thermal dependence of the gain medium's physical properties such as the thermal conductivity, the dn/dT and the expansion coefficient on the thermal aberration and thermal lensing values; we also prove that the choice of the resonator can influence the amount of spherical aberration.
Based on the computed results, the laboratory experiment is designed to model the thermal deformations aberration and the correction process by using two Liquid Crystal on Silicon Spatial Light Modulators (LCoS-SLM).
Simulation of the impact of different aberrations, thermal effects and residual pump light on the measurement of the M2 is provided.
Spherical aberrations of thermal lens of the active media are severe when the solid state lasers are strongly pumped.
Both simulated and experimental results indicate that the method of wavefront pre-compensation can greatly correct the aberrations caused from thermal deformation, and the laboratory experiment is a feasible method to modeling the inner optical system with phase aberration.
The phase aberration caused by thermal deformations in a high power inner optical system is simulated and the wavefront pre-compensation for correcting the aberration is studied experimentally.
In the measurement system of beam quality factor, M2, wave-front and intensity aberrations caused by optical elements, thermal effects, residual pump light, etc., influence the measurement results.
The experimental results show that the wavefront aberration of laser is mainly includes the defocus Z3, the low-order astigmatism Z4 and Z5, the spherical aberration Z10, etc. because of the thermal effect of gain medium, which will lay an experimental foundation for solid-state laser optimum design.
Aberration induced by both the optical components and the thermal effects in the amplification stages can be corrected with an adaptive optics system to reach both maximum peak energy and fluence.
