Abstract

Experimental demonstrations of squeezed and other nonclassical states of the electromagnetic field open the way to important improvements in the sensitivity of optical measurements below the limit imposed by shot noise. In particular, it has been shown that squeezed vacuum states can be used to enhance the sensitivity of interferometric measurements^1,2 and that the quantum correlation properties of the twin beams produced by a nondegenerate optical parametric oscillator (OPO)³ can improve the sensitivity of absorption measurements by ultralow loss media.^4,5

© 1990 Optical Society of America