Cindy Regal, Assistant Professor of Physics, University of Colorado Boulder
Optical interferometry is at the heart of precise measurement, as is well-known at Caltech where the most extreme of interferometers were conceived. Generally one improves interferometer precision by increasing the light intensity and trying to calm the many technical sources of noise that can perturb the mirrors or optical path. However, at strong light powers where radiation forces are significant, a new and interesting disturbance should appear – the quantum shaking associated with random arrival of individual photons at a mirror of the interferometer. This quantum backaction of light has been long foreseen in gravitational wave searches and played a formative role in quantum optics theory. In this talk I will discuss experiments in which we use a particularly compliant micro-scale, vibrating mechanical element to go 'looking for trouble' and observe this effect. In this strong-light limit, interferometer mirrors can also be used as a nonlinear medium to manipulate light – for example to make squeezed light (ponderomotive squeezing). Our miniature interferometers may find use in quantum information; in particular we are pursuing ways to translate more complex quantum states into light by coupling superconducting elements to our mechanical resonators.