Methods for Compensating Thermal Mode Distortions in High Average Power Chirped Pulse Amplifiers

Further development of a solid state, high average power, chirped pulse amplifier is presented. The design of a container filled with an optical gel, OCF-446, with a negative dT dn to compensate for thermal lensing effects in the amplifier is discussed along with designs of a thermoelectric cooling system for the solid state Ti:sapphire crystal in the amplifier. The container is a variable width cell which has a step size of .026 mm / 15 and prevents the OCF-446 from becoming dirty. Experimentation on this cell verifies that OCF-446 acts as a negative thermal lens when it comes in contact with a laser beam. Testing also concludes that a larger path length within the variable width cell leads to an increase in the beam waist. Thus the tunability of the cell’s effect on negative thermal lensing is shown to be successful since previous designs were static in path length. 1 Email: [email protected] 2 Email: [email protected]