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What are the main parts of a spectrometer?

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In the context of optical spectroscopy, a spectrometer is an instrument designed to accept light, separate it into its component wavelengths, and detect the resulting spectrum. To perform these functions, a spectrometer typically consists of three main parts:1

A radiation source: This provides the light or other electromagnetic radiation used to illuminate or excite the sample.21
A disperser: This component separates the radiation into its component wavelengths. Common methods of dispersion include the use of diffraction gratings, which utilize constructive interference to spread light into a spectrum.13
A detector: This system senses the presence of radiation after it has been dispersed, allowing for the measurement and analysis of the spectrum. In many modern systems, electronic photodetectors are used for their high sensitivity and linear response to light intensity.213

While these are the fundamental components, specific designs may vary depending on whether the device is used for emission or absorption analysis, or if it is intended to sort particles by mass, as in mass spectrometry.2