Thermal lens in diode-pumped square-section rods of Nd-doped phosphate glass and 0.5%Nd:5%Lu:CaF₂ crystal: simulations and experiments

Abstract

We performed simulations and experiments of wavefront distortions induced by propagating through diode-pumped square-section amplifying laser rods of Nd-doped phosphate glass and 0.5 % N d : 5 % L u : C a F 2 . We observed that depending on the material, wavefront distortions’ profile can vary from a circular lens-like distortion to a complex astigmatic distortion. We showed that this difference comes from the relative sign of piezo-optic tensor coefficients.

Comparison of simulation and experimental characterization of a 4-pass diode-pumped 4-active-mirrors 1053 nm laser amplifier

“…In this presentation, we will outline experimental performances of a 4-pass 4-active-mirrors amplifier with Nd: phosphate or Nd :Lu :CaF2 compared to thermooptical simulations using COMSOL [3] and propagation simulation using Miro [9].…”

“…For example, in the Laser MegaJoule preamplifier, thermal effects occurring in the flashlamp-pumped Nd-doped phosphate glass rod of the 4-pass amplifier limits the 1 Hz repetition rate of the regenerative amplifier to 1 shot every 5 min. Generally, thermal effects may appear as wavefront deformation [3]. To counteract thermal effects in the amplifier rods in high power laser, thin-disk amplifiers have been developed.…”

Thermal effects reduction in a diode side-pumped rod-like bonded α-quartz||Nd:glass||α-quartz amplifying medium

“…The heat generated during pumping propagates in the gain medium (𝑖 = 𝐴) and the heatsinks (𝑖 = 𝐻𝑆). The Fourier heat equation is expressed as [1,4]:…”

“…The refractive index tensor in an isotropic material (e.g. the laser glass) under thermal stress writes [1,4]:…”