Jones calculus modeling and analysis of the thermal distortion in a Ti:sapphire laser amplifier

Abstract

The mathematical modeling of an anisotropic Ti:sapphire crystal with a significant thermal load is performed. The model is expressed by the differential Jones matrix. A thermally induced distortion in the chirped-pulse amplification process is shown by the solution of the differential Jones matrix. Using this model, the thermally distorted spatio-temporal laser beam shape is calculated for a high-power and high-repetition-rate Ti:sapphire amplifier.

Thermal lens effect model of Ti:sapphire for use in high-power laser amplifiers

“…To develop applications of high-power lasers using Ti:sapphire, it is necessary to study the properties of Ti:sapphire and the thermal lens characteristics arising from its crystal structure. 14) The thermal lens expression in this study was derived in that context and was verified by comparing it with experimental results for known high-power laser amplifiers. [19][20][21] The design of a laser amplifier is dependent on its target specifications such as the target intensity, energy, and spatiotemporal shape of the generated pulses.…”

Modeling and Analysis of High-Power Ti:sapphire Laser Amplifiers–A Review

“…Ultra-high-power laser amplifiers use high-energy lasers as the source of the pump energy, imposing high thermal loads on the medium. This thermal distortion effect is one of the major causes of the degradation of the spatio-temporal quality of ultra-high-power laser pulses [21]. Because the non-involvement of the energy in the amplification process is a reason of the thermal effect, it becomes serious with the repetition rate.…”

“…In this section, we present the results of a study on the thermal effects of ultra-high-power laser systems that our group has conducted [21]. We will introduce the photo-elastic (PE) effect, which is relatively disregarded among the causes of the thermal distortion occurring in a CPA system using Ti:sapphire as the medium.…”

“…where π-tensor is a piezo-optical tensor, σ is the thermally induced stress, β is the angle between the principal axis of the thermal stress and Cartesian axis. However, because the deformation of a beam experiences not only thermal birefringence but also intrinsic birefringence and the amplification effect of the medium, they must be considered simultaneously [21]. To model the complete PE effect, the simultaneous consideration of the amplification of the medium and intrinsic birefringence is required.…”

“…In addition, we show how to apply the model to a CPA system and describe the analysis method of the square pump condition, which has attracted the interest of many research institutes in recent years [20]. Furthermore, an interpretation of the phase distortion occurring in the active medium, which has a significant impact on the energy and spatio-temporal shape of the pulse, is also included in this review [21,22]. The phase retardation generated inside a high-power laser medium, particularly in the case of Ti:sapphire, is relatively inadequately researched and is now essentially gaining attention for its effect [23].…”