Imaging Spectrometer - Disadvantages

Disadvantages

Imaging spectrometers have negative aspects like all man-made machinery. The lenses of the prism spectrometer are used for both collimation and re-imaging; however, the imaging spectrometer is limited in its performance by the image quality provided by the collimators and re-imagers. The resolution of the slit image at each wavelength limits spatial resolution; likewise, the resolution of optics across the slit image at each wavelength limits spectral resolution. Moreover, distortion of the slit image at each wavelength can complicate the interpretation of the spectral data.

The refracting lenses used in the imaging spectrometer limit performance by the axial chromatic aberrations of the lens. These chromatic aberrations are bad because they create differences in focus, which prevent good resolution; however, if the range is restricted it is possible to achieve good resolution. Furthermore, chromatic aberrations can be corrected by using two or more refracting materials over the full visible range. It is harder to correct chromatic aberrations over wider spectral ranges without further optical complexity.