Suppression Method of Thermal Lens Effect in High Energy Ti:Sapphire Multipass Amplifier

Abstract

Provided is a high-energy Ti sapphire multipass amplifier thermal lens effect inhibition method, comprising: through calculation, determining the thermal lens focal length of Ti sapphire under concrete pumping conditions; creating a corresponding lens array according to the space layout of an amplifier; based on the hypothesis of amplifying output collimating plane waves, utilizing an ABCD matrix to reversely calculate the radius of signal light at the convex lens in a beam expanding system and the convergence angle of a light beam; and designing a corresponding beam expanding system according to real incoming signal light, allowing the radius of signal light at the convex lens after beam expanding to be the same with a calculated value, and possess a divergence angle equal with the convergence angle, thereby compensating for the thermal lens focusing effect for the light beam. The method can completely compensate for the light beam focusing generated by thermal lenses under the condition of not introducing extra chemical elements, avoid laser material damage caused by thermal self-focusing, and effectively increase amplifier energy extraction efficiency. The method is simple and efficient and has strong practicality.

Description

technical field [0001] The invention relates to a titanium sapphire laser amplifier, in particular to a method for suppressing the thermal lens effect of a high-energy titanium sapphire multipass amplifier with a certain repetition frequency, a large beam size and a telephoto thermal lens. Background technique [0002] The invention of chirped pulse amplification (CPA) technology has opened up a new path for ultrashort and ultra-intense lasers; since the 1990s, CPA technology has developed rapidly. :Sapphire) hundreds of terawatts (TW) or even several petawatts (PW) level laser devices. Such a high peak power laser system provides humans with unprecedented new experimental means and extreme physical conditions. In such high peak power laser systems, multipass amplifiers generally use high average power laser pulses as pump light. During the amplification process, except a part of the pump energy absorbed by Ti:Sapphire is converted into laser light, most of the energy is c...

AI Technical Summary

Problems solved by technology

Therefore, the method is limited in high energy Ti:Sapphire multipass amplifiers

[0005] (2) Compensate thermal lens focusing by introducing additional optical elements or optical systems, such as introducing a negative lens or a beam expander system to compensate for thermal lens focusing during the magnification process, thereby improving the size match between the signal light and the pump light, but This will inevitably increase the complexity of the system

[0006] (3) Using liquid nitrogen to cool Ti:Sapphire crystal at low temperature, this method can effectively remove the thermal lens effect, but the use of liquid nitrogen is expensive and the process is relatively complicated

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