Advanced Quality Control Instruments and Services for Ultrafast Laser Optics

c. Advanced Quality Control Instruments and Services for Ultrafast Laser Optics As scientific laser systems increase in repetition rate and peak power, the quality of optics and damage threshold of optics becomes increasingly critical. Laser Induced Damage Threshold (LIDT) and the overall performance of optics for high average power (HAP) and high peak power (HPP) applications varies greatly. Both linear optics (e.g., mirrors, gratings and transmissive optics), and nonlinear optics (e.g., gain materials, harmonic generation crystals) often perform quite differently, even from the same manufacturer. Instrument for LIDT characterization. The surface preparation process is a critical factor in LIDT, and new and more accurate physical characterization methods are needed to improve fabrication processes and to qualify HAP optics. Techniques for revealing the causes of LIDT performance variations are of interest and include such techniques as fluorescence microscopy and photo-thermal heterodyne interferometry. Instruments for Large-Aperture Optic Characterization. Equally important are high accuracy optical characterization capabilities suitable for large-format HAP and HPP optics that can range from cm-scale nonlinear crystals to meter-scale diffraction gratings. Properties such as the reflected/diffracted/transmitted wavefront error, dispersion uniformity, and doping concentration uniformity need to be accurately measured at sufficient spatial resolution (e.g. millimeter or better) over the full optical aperture. Stitching interferometry for linear optics, like mirrors & gratings, and deuteration mapping for DKDP crystals are of particular interest. The successful proposal will propose (1) the development of an instrument, (2) measurement techniques, including data reduction and error estimation, (3) measurement validation and calibration techniques, and (4) complete a set of demonstration measurements on ultrafast HAP optics. An instrument capable of multiple simultaneous measurements (e.g., LIDT and doping concentration) would offer added efficiency and is especially interesting. Final demonstration measurements must be made in the near-IR (0.7-2.5 micron wavelengths) for ultrafast optics (10% bandwidth). If proposing an instrument to characterize LIDT, spatial resolution must be better than 1 mm, and the instrument must be capable of mapping a 4 cm diameter aperture, minimum. If proposing a dopant concentration instrument, accuracy must be 0.05 at% or better in the dopant concentration, with a spatial resolution of 1 mm or better. If proposing a wavefront characterization instrument, accuracy must be lambda/10 RMS or better over a 10 cm x 10 cm single field, and the instrument must have the capability to accurately stitch fields together over at least a 100 cm x 100 cm full aperture Questions Contact: Eric Colby, eric.colby@science.doe.gov