Mechanical structures feel the chill

The use of lasers to cool a macroscopic cantilever to a temperature of 18K was analyzed by controlling the motion of atoms and molecules. A silicon cantilever was used as one of the mirrors of a tuneable Fabry-Pérot resonator. A probe laser beam with a wavelength of 633 nm was sent down the optical fiber and the intensity and spectral properties of the reflected light were computed. It was found that when the power was increased, the heat due to the partial absorption of light by the cantilever was sufficient to cause it to bend, which altered the reflectivity of the cavity.