
Accession Number : ADP006705
Title : Beam Fanning in CoupledWave Theory of 2Beam Coupling,
Corporate Author : ROCKWELL INTERNATIONAL THOUSAND OAKS CA
Personal Author(s) : Ewbank, M. D. ; Vachss, F. R. ; Vazquez, R. A
Report Date : 22 MAY 1992
Pagination or Media Count : 4
Abstract : Simple coupledwave theory accounts for depletion of the pump beam due to energy transfer (i.e., amplification) to the probe beam. Ignoring absorption, the probe gain g can be expressed as g = I sub 1(z) divided by I sub 1(O) = 1+r sub pp divided by 1+r sub pp e to the Gamma z where I sub 1(O) is the incident probe intensity, Gamma is the twobeamcoupling coefficient and r sub pp is the incident pumptoprobe beam ratio given by r sub pp = I sub 2(O) divided by I sub 1(O) with I sub 2(O) being the incident pump intensity. Equation (1) remains valid even when the pumptoprobe ratio r sub pp is not sufficiently large (only the approximation for the probe gain g approximates e to the gamma L becomes invalid when r sub pp is not much greater than e to the gamma l). Similarly, the pump depletion d can be expressed as d = I sub 2(z) divided by I sub 2sO) = 1+r sub pp divided by r sub pp + e to the gamma z. These expressions for the probe gain and pump depletion have proven inadequate in describing the twobeamcoupling process, particularly when the coupling coefficient IF is very large (recently, r's exceeding 60/cm have been reported.
Descriptors : *OPTICAL PUMPING, ABSORPTION, COUPLINGS, DEPLETION, ENERGY, EQUATIONS, GAIN, INTENSITY, PROBES, PUMPS, RATIOS, THEORY, REFRACTION, SYMPOSIA.
Subject Categories : Optics
Distribution Statement : APPROVED FOR PUBLIC RELEASE