A High-Harmonic Generation Source Sized by the Cutoff Law and Phase-Matching Pressure

This paper presents a computed design for a gas-cell high-harmonic generation source driven at 800 nm, producing extreme-ultraviolet pulses with a spectral cutoff near 46 eV. 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 drive intensity of 1.6e+14 W/cm2, a ponderomotive energy of 9.6 eV, a cutoff photon energy of 46 eV reaching harmonic order 30 of the drive, and an order-of-magnitude flux near the cutoff of 6.8e+08 photons per second at 1 kHz under the stated conversion assumption. The binding constraint is identified explicitly: absorption of the generated harmonics in the same gas that produces them, which caps the useful cell length and pressure product. 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.