Intrinsic Optical Bistability in a Cavity

Redstone Arsenal

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

We have experimentally demonstrated a fundamentally new type of intrinsic optical bistability. The operation of this new class of device is based on self-focusing of a laser beam as it propagates through a nonlinear medium. It further differs from previous optical devices which exhibited intrinsic bistability (only optical feedback, no electrical feedback) in that the earlier devices have all required resonant optical cavities; no such cavity is required for this new type of device.

C. M. Bowden

Michael Scalora, Joseph W. Haus, C. M. Bowden

A nonlinear oscillator model is used as a prototypical medium for intrinsic optical bistability.1 The phenomenon of intrinsic optical bistability is so named because the medium does not require the optical feedback of a cavity. In this model we retain dispersive effects and introduce a diffractive coupling of the electromagnetic field amplitude. The threshold of the optical bistable device is insensitive to the Fresnel number, which determines the coupling between field amplitudes at different transverse positions.2 This is useful for obtaining reproducible operating characteristics of an array of devices. The medium can be introduced inside a cavity to understand the role of dispersive and diffractive effects in a more fundamental way. The threshold intensity is again insensitive to the Fresnel number. Furthermore, we observe instabilities in the cavity configuration, but no chaotic solutions were found. The periodic instabilities are sensitive functions of the Fresnel number.

R. J. Ballagh, J. Cooper, M. W. Hamilton +2 more

Andy C. Walker, S. Aitchison, John Chilwell +2 more

Intrinsic optical bistability has been observed in a GaAlAs slab waveguide as a result of a dispersive nonlinearity. The guiding layer was 1.7 μm thick, contained ~ 7% Al and was bounded by GaAlAs layers of higher Al content. An optical cavity was formed by cleaving the guide ends and leaving these surfaces uncoated (~ 32% reflectivity). The length of the cavity was ~ 200 μm.