Abstract

It is well known that in dense media the effective field acting on an atom/molecule is no longer the macroscopic field but the so-called local field, which is due to all external sources and to all dipole moments of the atoms/molecules within the sample except the one under consideration [1]. The inclusion of the local field effects gives rise to the prediction of a large number of interesting phenomena in optical systems, such as spectral red shifts, mirrorless optical bistability, "piezophotonic" effects, and enhancement of inversionless gain and absorptionless index in lasing without inversion. As an example, a density of 10¹⁷atoms/cm³ of sodium atoms is sufficient to give rise to a shift of about 1 GHz of the sodium D line.

© 2000 IEEE