Theoretical analysis of an end-pumped Yb:YAG active mirror thin-disk amplifier with a longitudinal doping concentration gradient.

In this paper, we present a theoretical derivation of the amplification in a longitudinally pumped amplifier with a doping gradient concentration optimized for obtaining a constant longitudinal gain. This technique makes it possible to reduce both the effect of the amplification of the spontaneous emission (ASE) and the temperature gradient. We will express the longitudinal concentration profile as a function of the amplifier parameters and the launched pump intensity.

Distortion cancellation of frequency converted pulses with simple linear signal processing and application to frequency modulation to amplitude modulation conversion in high power lasers.

It is known that a linear filter may be easily compensated with its inverse transfer function. However, it was shown that this approach could also be valid even for such a complex nonlinear system as frequency conversion. As a matter of fact, it is possible to at least partly precompensate for distortions occurring within, or even downstream from, frequency conversion crystals with a simple linear optical filter set upstream.

Simple analytical derivations of thermal lensing in longitudinally Q-CW pumped Yb:YAG.

In this paper, we introduce analytical derivations for the thermal lensing of an end-pumped laser disk. These derivations are done for pump beam shapes from Gaussian to top hat, assuming that the thermal conductivity is either constant with the temperature or not. We give examples in two temperature regions, where the thermal conductivity exhibits T(-1) or T(-2) dependence.

Nonsinusoidal phase modulations for high-power laser performance control: stimulated Brillouin scattering and FM-to-AM conversion.

High-power lasers, such as the Laser MegaJoule (LMJ), have to be phase modulated to avoid stimulated Brillouin scattering (SBS) that may strongly damage optics at the end of the laser chain. Current spectral broadening on LMJ is performed with a sinusoidal phase modulation. This pure sinusoidal phase modulation leads to inhomogeneous spectral power densities (SPD).

FM-to-AM conversion in high-power lasers.

FM-to-AM conversion is an important issue that could prevent fusion ignition with high-power lasers, such as the Laser MegaJoule (LMJ). We first overview the whole problem of FM-to-AM conversion in high-power lasers and we explain why AM spectral content of FM-to-AM conversion is important, although this information was not used in previous studies. We then propose simple analytical models to simulate FM-to-AM conversion in the LMJ frequency conversion system.