将复色光分离成光谱的光学仪器。光谱仪有多种类型，除在可见光波段使用的光谱仪外，还有红外光谱仪和紫外光谱仪。按色散元件的不同可分为棱镜光谱仪、光栅光谱仪和干涉光谱仪等。按探测方法分，有直接用眼观察的分光镜，用感光片记录的摄谱仪，以及用光电或热电元件探测光谱的分光光度计等。单色仪是通过狭缝只输出单色谱线的光谱仪器，常与其他分析仪器配合使用。
An optical instrument for separating polychromatic light into spectra. There are many types of spectrometers. In addition to the spectrometers used in visible light, there are infrared spectrometers and ultraviolet spectrometers. According to the different dispersion components, it can be divided into prism spectrometer, grating spectrometer and interference spectrometer. According to the detection methods, there are spectroscopes for direct eye observation, Spectrographs for recording with photographic films, and spectrophotometer for detecting spectra with photoelectric or thermoelectric elements. Monochromator is a kind of spectral instrument which only outputs monochromatic spectral line through slit. It is often used with other analytical instruments.