optics Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...

, optical bistability is an attribute of certain

optical device Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...

s where two resonant

transmissions state Transmission may refer to: Medicine, science and technology * Power transmission ** Electric power transmission ** Propulsion transmission, technology allowing controlled application of power *** Automatic transmission *** Manual transmission * ...

s are possible and stable, dependent on the input. Optical devices with a

feedback mechanism Feedback occurs when outputs of a system are routed back as inputs as part of a Signal chain (signal processing chain), chain of Causality, cause-and-effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. ...

, e.g. a

laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...

, provide two methods of achieving

bistability In a dynamical system, bistability means the system has two stable equilibrium states. Something that is bistable can be resting in either of two states. An example of a mechanical device which is bistable is a light switch. The switch lever ...

. *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 In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or ...

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. Optical bistability was first observed within vapor of sodium during 1974.

Intrinsic bistability

When the feedback mechanism is provided by an internal procedure (not by an external entity like the mirror within the Interferometers), the latter will be known as intrinsic optical bistability. This process can be seen in nonlinear media containing the

nanoparticles A nanoparticle or ultrafine particle is usually defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 1 ...

through which the effect of

surface plasmon resonance Surface plasmon resonance (SPR) is the resonant oscillation of conduction electrons at the interface between negative and positive permittivity material in a particle stimulated by incident light. SPR is the basis of many standard tools for measu ...

can potentially occur.Sharif, Morteza A., et al. "Difference Frequency Generation-based ultralow threshold Optical Bistability in graphene at visible frequencies, an experimental realization". ''Journal of Molecular Liquids'' 284 (2019): 92–101. https://doi.org/10.1016/j.molliq.2019.03.167

References

* {{cite book, author1=Guangsheng He, author2=Song H. Liu, title=Physics of Nonlinear Optics, url=https://books.google.com/books?id=CqYTqT9kQDUC&pg=PA422, year=1999, publisher=World Scientific, isbn=978-981-02-3319-8, pages=422–