Nonlinear optical devices

Abstract

In linear optics, photons are regarded as noninteracting and it has been the noninteracting nature of photons that has made them particularly useful in the communication of information. Nonlinear optical effects become significant at high intensities of light where the photons are observed as interacting. In linear optics, it has been the communication aspect which has driven much of modern research in optoelectronics to the point where the technology of light generation and confinement has reached a stage where high intensities light can be maintained over long interaction lengths and significant nonlinear optical effects can be observed and utilized. Nonlinear optics offers the intriguing possibility that interacting photons can be employed in several ways including: the generation of coherent light at new frequencies where there are no convenient laser sources; the generation of ultrashort pulses of light; the propagation of ultrashort pulses without distortion from linear dispersion; and in processing of information. It is an interesting thought that in nonlinear optics the situation is the reverse of superconductivity where a usually highly interacting fermion, the electron, is induced to adopt noninteracting photon-like qualities.