3. Conclusion

The volume acousto-optics we have just described are based on mature, reliable and well-understood technologies. In practice, it is not uncommon to be able to use components that are decades old and still working satisfactorily. Paratellurite has been the "miracle" material behind the industrial development of acousto-optic components since the end of the 20th century; its acousto-optic properties are exceptional, crystal growth is well controlled and the resulting crystals are often of excellent optical quality. For elastic volume wave transducers, about which we haven't said much, the leading material is lithium niobate. This is a piezoelectric crystal with high electromechanical coupling coefficients, transparent over a wide optical spectrum and compatible with radio frequencies. Overall, manufacturing technologies are mature, for crystal growth and orientation, polishing, anti-reflective...