Quantum beam collapse in a self-focusing medium

P. W. E. Smith, D. J. Eilenberger

Two years ago, the first proposal and demonstration of self-focusing optical bistability was published.1 In this paper it was shown that a self-focused beam in a nonlinear medium would exhibit hysteresis if the beam were reflected back on itself. The effect was demonstrated using a dye laser beam and Na vapor as the nonlinear medium. The optical hysteresis observed is in good qualitative agreement with a recently - published analysis of this system.2 By taking account of the saturation of the nonlinearity, more complex behavior has been predicted.2 This behavior is due to oscillations of the spot size as the self-focused beam propagates through the nonlinear medium. In this paper we report on our experimental studies of optical multistability due to these spot size oscillations.

Ramarao Inguva

John E. Bjorkholm, P. W. E. Smith, W. Tomlinson +3 more

We experimentally demonstrate a fundamentally new type of intrinsic optical bistability that requires no resonant optical cavity. Operation is based on mutual self-focusing of counterpropagating laser beams in a nonlinear medium. We propose and experimentally demonstrate a fundamentally new type of optical bistability. 1 The operation of this new class of devices is based on self-focusing of light; the feedback required for bistability is provided by an apertured retroreflector. These devices exhibit intrinsic bistability (the feedback is optical) and are related to nonlinear waveguide devices proposed earlier. 2 Self-focusing occurs when a light beam having a nonuniform spatial profile (such as a Gaussian laser beam) and sufficient intensity propagates through a nonlinear medium having an intensity-dependent index of refraction. 3 Previously proposed devices that exhibited

N. Bloembergen

Weiping Zhang, Barry C. Sanders, Weihan Tan

Light-induced dipole-dipole interactions in a coherent atomic field result in an effective nonlinear interaction between atoms. This nonlinearity can induce self-focusing and self-trapping of a coherent atomic beam undergoing propagation through a travelling-wave laser beam; we show how such a scheme could be realized and evaluate the critical density required for atomic self-focusing and self- trapping. An analogy to optical self-focusing and self- trapping is discussed.

Miguel Orszag, J. C. Retamal