PhoSim (The Photon Simulator)
Welcome to the official Photon Simulator (PhoSim) site! PhoSim is a set of extremely fast photon Monte Carlo codes that calculate the ab initio physics of the atmosphere and a telescope & camera in order to simulate realistic optical/UV/IR/X-ray astronomical images. PhoSim can also simulate any optical system that produces images (e.g. cameras, satellites, human eye).
PhoSim does this using modern numerical techniques applied to the physical response of photons (and electrons) to comprehensive physical descriptions of the atmosphere, telescope, and camera. After these detailed physics calculations, PhoSim simply generates images by collecting electrons into pixels. The photon simulations below (Rubin [below left], JWST [below middle], WIYN [below right]) show the photon Monte Carlo method where photons and electrons are physically propagated through the system. The photon/electron interaction physics includes the appropriate application of novel advanced raytracing, diffraction, and quantum mechanical interactions.