For high power laser applications, thermal lensing can be an issue. Focal length can vary with running time as a result of heat build-up in optics due to power throughput. The TLC, or Thermal Lensing Compensation optic design from Haas Laser Technologies, passively compensates for thermal lensing for high power collimators and focal lenses. Thermal lensing for lasers with powers in excess of 1kW is reduced to less than the Rayleigh range of the lens design, through careful selection of materials and optical design.
TLC optics incorporates a balancing of the dn/dT between two high power laser optical materials. Using a proprietary optical design merit function, thicknesses, air spacing and curvatures are optimised to minimise thermal lensing between 20°C and 250°C.
Using TLC optics will eliminate the need to wait for minutes for a system to become thermally stable. The laser will be in focus from the moment it is turned on.