CORRELATION BETWEEN GAIN WITHOUT INVERSION, ENHANCED REFRACTIVE-INDEXAND NOISE IN A LAMBDA-3-LEVEL SYSTEM

The gain, the refractive index and the noise on the gain are analysed for the case of a weak probe propagating through a medium of driven de generate Lambda three-level atoms. They are all found to have the same linear dependence on the rate of the collisional relaxation rate betw een the two low-lying states of the Lambda three-level system. This in dicates that a correlation exists between the gain without inversion, the enhanced refractive index and noise in this system. Furthermore, t he maxima in the noise occur at the points of non-absorption in the ga in spectrum which are also the extremum points in the refractive index spectrum.