Design Blueprint: A Cavity-Enhanced Frequency-Comb Spectrometer Sized by Effective Path Length and Absorption Sensitivity

Design blueprint derived from the source paper (DOI 10.5281/zenodo.24155217): This paper presents a computed design for a cavity-enhanced direct frequency-comb spectrometer covering a broad near-infrared band in a single acquisition. 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 effective absorption path of 12 km from a 0.60 m physical cavity, a finesse near 62830, a minimum detectable absorption coefficient of 8.3e-08 per metre per spectral element, and about 40000 spectral elements recorded in parallel Status: DESIGN BLUEPRINT — SIMULATED, NOT MEASURED — NOT BUILT. All numbers are simulated values from the source paper's computation, deposited with this blueprint as compute.py and results.json. AI-use disclosure: Dave, an AI research system, assisted with the computation and drafting under the author's direction; author of record William Alexander Aldred.