Irradiance

Irradiance is a physical quantity describing the power density of optical radiation incident on a unit surface area, expressed in watts per square meter (W/m²).

How is irradiance determined?

In optical simulations, irradiance on a given surface (e.g. a screen, detector, or work surface) is determined by summing the energy of all light rays reaching each point of that surface in a Monte Carlo ray tracing simulation. The result is an irradiance map — a two-dimensional distribution of radiation intensity.

Applications

Irradiance maps are a basic tool for assessing lighting-design quality (uniformity of illumination, peak values), analyzing the energy reaching detectors in scientific instruments, and designing solar-energy concentration systems.

Related terms

Monte Carlo method in optics

UGR

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