What devices are used to measure wavelengths in an LED?
A spectroradiometer separates light into wavelengths and measures the intensity of each wavelength. The device, which splits the light into individual wavelengths, is a series of closely spaced parallel grooves on glass. The distance between the parallel grooves determines what wavelength will pass through. For a given spacing, only one wavelength will pass through. Shorter and longer wavelengths are blocked. After the wavelength passes through the grating, a light sensor (which may be a photo multiplier tube or a solid-state sensor such as a silicon photodiode) measures the intensity.
