High-energy Ti sapphire multipass amplifier thermal lens effect inhibition method

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 Ti:Sapphire laser amplifier, in particular to a method for suppressing the thermal lens effect of a high-energy Ti:Sapphire multi-pass amplifier with a certain repetition frequency, a large-size beam, and a long focal thermal lens. Background technique [0002] The invention of Chirped Pulse Amplification (CPA) technology has opened up a new path for ultra-short and super intense lasers; since the 1990s, CPA technology has developed rapidly. So far, many countries in the world have established titanium-sapphire crystals (Ti :Sapphire)’s hundreds of terawatts (TW) or even several petawatts (PW) laser devices. Such a high peak power laser system provides humans with unprecedented new experimental methods and extreme physical conditions. In such a high peak power laser system, the multi-pass amplifier generally uses high average power laser pulses as the pump light. During the amplification process, except for part of the pump ener...

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