Optical bistability

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In optics, optical bistability is an attribute of certain optical devices where two resonant transmissions states are possible and stable, dependent on the input. Optical devices with a feedback mechanism, e.g. a laser, provide two methods of achieving bistability.

  • Absorptive bistability utilizes an absorber to block light inversely dependent on the intensity of the source light. The first bistable state resides at a given intensity where no absorber is used. The second state resides at the point where the light intensity overcomes the absorber's ability to block light.
  • Refractive bistability utilizes an optical mechanism that changes its refractive index inversely dependent on the intensity of the source light. The first bistable state resides at a given intensity where no optical mechanism is used. The second state resides at the point where a certain light intensity causes the light to resonate to the corresponding refractive index.

This effect is caused by two factors

  • Nonlinear atom-field interaction
  • Feedback effect of mirror

Important cases that might be regarded are:

  • Atomic detuning
  • Cooperating factor
  • Cavity mistuning

Applications of this phenomenon include its use in optical transmitters, memory elements and pulse shapers.