An Optical Parametric Chirped-Pulse Amplifier Sized by Parametric Gain and Photon-Energy Partition

This paper presents a computed design for a three-stage optical parametric chirped-pulse amplifier (OPCPA) pumped at 515 nm, amplifying a 800 nm signal and generating a 1446 nm idler. 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 an idler wavelength fixed by energy conservation at 1446 nm, a final-stage pump energy of 120 mJ with 55% depletion, a signal output of 42.5 mJ and an idler output of 23.5 mJ, with the Manley-Rowe partition capping the signal at 64.4% of every converted pump photon's energy. The binding constraint is identified explicitly: back-conversion at the chosen pump intensity and angular dispersion from the non-collinear geometry degrading the focus. 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.