= Spectrometer
{wiki}
A <spectrometer> measures a signal as a function of a spectral variable. An optical <spectrometer> commonly separates <wavelengths> with an <optical prism> or a <diffraction grating>, then records the separated <light> with a <photodetector>. A <spectrograph> records many spectral positions together; a <monochromator> selects a narrow interval for a subsequent measurement.
An entrance slit, collimating optics, dispersing element and focusing optics make a simple grating instrument. Narrowing the slit can distinguish closer <spectral lines> but admits fewer <photons>. A lamp with known <spectral lines> calibrates the <wavelength> scale, while a blocked input estimates background. Brightness at a detector position becomes a sample <optical spectrum> only after accounting for the instrument's wavelength-dependent response.
Back to article page
