What is a Spectrometer?

A focus on different types of spectrometers, and what they are used for.

In the broadest sense a spectrometer is any instrument that is used to measure the variation of a physical characteristic over a given range; i.e. a spectrum. The most ubiquitous type of spectrometer used for research are optical spectrometers; and when someone simply says ‘spectrometer’, without an additional qualifier, they are usually referring to an optical spectrometer and this diverse family of spectrometers is the focus of this article.