Acousto-optic scanning instruments

There are several measurement techniques that can be considered for use in IR-based instrumentation in the NIR and the mid-IR spectral regions, and these are summarized in Table 4.1. Some of these techniques are classical, as in the case of optical filter-based instruments and scanning monochromators. Others, such as acousto-optically tunable filter (AOTF), have been considered for 15+ years, but are mainly applied to NIR... 

Acousto-optic tunable filters (AOTFs) are solid-state, rapid scanning instruments. The heart of the instrument is an anisotropic crystal (Figure 2.4) capable of splitting a particular wavelength of light into its ordinary and extraordinary (clockwise and counterclockwise rotated) rays. One face (orthogonal to the light beam) has a transducer bonded to it. 

FT-instruments grating, filter. FT and acousto-optical tunable scanning instruments... 

---