Many methods can be employed to measure mechanical displacement; the coupling of optical and mechanical degrees of freedom is behind many of these techniques.
This mutual coupling of optical and mechanical degrees of freedom in an optical cavity has been explored in interferometers; better and known as cavity optomechanics.
Researchers from Germany and the United States [Kippenberg et al., Science (2008) 321, 1172] discuss the phenomenon of back-action of photons caused by radiation pressure which can influence the dynamics of such systems, leading to a plethora of new phenomena, some of which may spurn innovative technologies as well as aiding the further understanding of fundamental science.
Kippenberg et al., present a concise review, providing some thoughts and solutions in this area and insights in to some of the applications for this technology in the future.
The paper discusses the increasing importance of the radiation pressure which takes place during the reflection of the photons. This phenomenon will become increasingly important as electronic devices continue to decrease in size.
Cavity optomechanics may ultimately find applications in many areas; the ability to provide targeted cooling of nano and micromechanical oscillators, is one key area under investigation. Applications will also include areas such as scanning probe techniques and gravitational wave detection. Another application area of great interest is in gradient-force control of mechanical structures using cavity optomechanical effects.
Radiation-pressure coupling has opened an extremely broad scope of application, both applied and fundamental, and with the continuing demand for ever smaller components and devices it will become an increasingly important phenomenon.
Cavity optomechanics may well provide a way to probe the quantum environment of mechanical systems and give rise to entirely new ways of controlling mechanics, light or both. Techniques and applications may also be found in the area of device cooling and signal amplification.