Laser
Emits a CW or pulsed monochromatic, broadband, supercontinuum, or sized collimated beam.
Open in the canvas →In the real world
A laser produces light by stimulated emission inside a resonant cavity: a gain medium bounded by two mirrors amplifies a specific wavelength every round trip, while losses (mirror transmission, absorption, scattering) drain it. Above threshold — the pump rate at which round-trip gain first equals round-trip loss — the cavity sustains a stable, highly monochromatic, spatially coherent beam.
The output isn't a perfectly parallel ray bundle: real laser beams are Gaussian and diverge with propagation. For a beam with waist radius w₀, the far-field half-angle divergence is
In OpticalSetup
The Laser element emits either a single collimated ray or, in Beam with size mode, a fan of 25 parallel rays sampling a finite beam width — this is what lets the tracer show a lens actually focusing a beam of nonzero extent, rather than a single infinitesimal ray that can never miss an aperture.
Spectrum is monochromatic, broadband (a symmetric bandwidth around the center wavelength), or supercontinuum (a fixed 430–870 nm white-light band) — dispersive elements downstream (prisms, gratings) sample this band at several discrete wavelengths and fan them out individually. Pulsed mode adds a repetition rate and pulse duration that drive the timing overlay; polarization is set directly as a Stokes vector rather than emerging from a modeled cavity.
There is no modeled gain medium, cavity round trip, or threshold — wavelength, spectrum, polarization, and pulse timing are configured directly as source parameters, not derived from first principles. Divergence and M² are not modeled: a collimated beam stays perfectly parallel over any distance.