The Quiet Light Experiment: Searching for Technosignatures through Multilayer Photonic Analysis of Astronomical Light

The Quiet Light Experiment (QLE) is a modular astrophotonics program designed to test whether subtle photonic properties of astronomical light may reveal novel physical processes or engineered modulation. While conventional SETI has concentrated on narrowband radio and optical pulses, modern quantum optics and astrophotonics provide access to richer photon observables that remain almost completely unexplored. QLE focuses on three domains: orbital angular momentum surveys that establish the first systematic catalogue of spatial modes in Solar System and stellar light; quantum randomness analysis that compares photon-derived bitstreams against thermal baselines to search for reproducible entropy deviations; and fine spectral structure studies that use high-resolution spectroscopy to detect narrow combs, spikes, or anomalous features not attributable to known astrophysical mechanisms. Each of these layers is independently valuable: null results yield publishable datasets in astrophotonics, turbulence modelling, and quantum optics, while positive results are advanced only when corroborated across multiple domains. More speculative probes, such as contextuality and observer-related quantum tests, are confined to appendices and applied only if core layers indicate candidate anomalies. In this framework, QLE functions as a disciplined astrophotonics testbed that guarantees credible science while opening new pathways for technosignature exploration