光谱仪的参数
波长精度（Wavelength accuracy）是指设备在选定波长下运行的能力。换言之，如果某仪器选定的中心波长为546nm，实际的中心波长可能低至544.5，或高至547.5，则该仪器的波长精度为±1.5 nm，波长精度又称为波长准确度，这个参数体现了仪器选定波长的真实性和准确性。
注意：你只是知道有这种可能但是并没法用这个仪器确定，要确定波长精度需要第三方精度更高的仪器去检验；
波长再现性（Wavelength reproducibility）是指设备返回相同波长的能力；同样，如果先使用了546nm，然后更改设置为不同的波长，然后再将其返回到546nm，返回后，可能显示为546.1和545.9nm之间，则其再现性为±0.1nm。波长再现性也可称为波长精密度（Wavelength precision），体现了波长的精确程度。
波长分辨率（Wavelength resolution）是指波长的选择分辨率。比如5nm分辨率，则只能选择输出400nm ，405nm，410nm等的数据，而不能获取407nm的数据。
这三个参数都与设备将衍射光栅旋转到已知位置（精度）、特定位置（精密度）和分光（分辨率）的能力有关。
带宽（Bandwidth）则与测量光的光谱纯度有关，主要由出口狭缝宽度控制。相比之下，激光产生真正的单色光或只有一个频率的光。
单色仪对通常包含多个频率或波长的光的色散光谱要进行稀疏采样。根据我们上面的例子，选择546nm的波长（实际上可能是546.8nm），探测采集的光包括波长544.3到549.3，则带宽为5nm。在大多数光谱仪中，狭缝宽度通常是固定的。虽然单色仪的带宽主要由出口狭缝宽度控制，但在具有固定出口狭缝宽度的单色仪中，由衍射光栅分散的光的入射角也会导致带宽随波长而变化。
Wavelength accuracy is the ability of the device to operate at the select a wavelength. In other words if I select a center wavelength of 546nm, the real center wavelength emitted through the sample may be as low as 544.5 or as high as 547.5 based on a wavelength accuracy of ± 1.5 nm (The wavelength accuracy varies from instrument to instrument. Check your owner’s manual for your specific instrument specifications).
Wavelength reproducibility is the ability of the device to return to the same wavelength; so again, if I select 546nm, (and the device actually went to 546.8nm due to the wavelength error in accuracy), then set the spec to a different wavelength, and then return it to 546 nm, upon return I would expect the wavelength to be set to the original wavelength +/- 0.1nm or between 546.7 and 546.9nm.
Wavelength resolution is the wavelength selection resolution. All of these first 3 parameters are related to the ability of the device to rotate the diffraction grating to known position (accuracy), a specific position (precision), and with resolve (resolution).
Bandwidth is related to the spectral purity of the light emitted through the sample and is controlled mostly by the exit slit width. In contrast, a laser produces true monochromatic light or light of only one frequency. A monochromator selects a small sampling of a dispersion spectrum which generally contains more than one frequency, or wavelength of light. As per our example above, selecting a wavelength of 546nm, (actually 546.8nm), the emission through the sample would comprise wavelengths 544.3 to 549.3, a bandwidth of 5 nm. The slit width is generally fixed in most spectrometers. Although the bandwidth of a monochromator is mostly controlled by the exit slit width, in a monochromator with a fixed exit slit width, the incident angle of light which is dispersed by the diffraction grating can also contribute to small bandwidth changes as a function of wavelength.