Wiki / Detectors / Photodetector

Photodetector

Measures qualitative ray signal, spectrum, polarization, and spot span.

Open in the canvas →

Click the photodetector to see its live specs and try its parameters — this mini canvas can't be moved, deleted, or added to.

In the real world

A real photodetector converts incident optical power to an electrical photocurrent with some responsivity R (amps per watt), set by the detector's quantum efficiency η — the fraction of incident photons that produce a collected charge carrier:

R=ηehν[A/W]R = \frac{\eta e}{h\nu} \quad [\text{A/W}]
Responsivity of an ideal photodetector at optical frequency ν.

In OpticalSetup

The detector reports a qualitative relative signal — the sum of every ray's intensity reaching its front face — plus the spectrum, polarization state, and spot extent of whatever light arrives, all read directly off the traced rays. This is genuinely useful for seeing whether light reaches a detector, roughly how strong it is relative to other configurations, and what its spectral or polarization content is.

Simplified vs. reality

The reported signal is not calibrated to any real unit — there is no watts-in, amps-out responsivity curve, no dark current, no saturation physics beyond what's explicitly modeled on the PMT variant. Treat the number as relative, not absolute.

Related components

Further reading