A Treacy Grating-Pair Compressor for a 100 J Beam Sized by Dispersion, Separation and Grating Aperture

This paper presents a computed design for a four-grating Treacy compressor recompressing a 100 J, nanosecond-stretched pulse at 800 nm to the femtosecond range. The sizing follows from applying the relevant intensity, thermal, nonlinear and geometric bounds at a single stated operating point, with every number produced by a deposited computation. The headline result is a Littrow angle of 36.3 degrees, a dispersion of 7.59e+06 fs2 per metre of pair separation, a required separation of 1.05 m to cancel the stated stretcher chirp, gratings 0.34 m long for the 20 cm beam, and a four-grating throughput of 0.78 delivering 78 J from 100 J in. The binding constraint is identified explicitly: grating damage at the final grating, where the pulse is shortest, and wavefront distortion from grating surface figure at metre scale. The design is SIMULATED, NOT MEASURED: no hardware was built for this study, and all performance figures are predictions from stated assumptions, offered as a basis for a build decision and a measurement plan.