Light bullets are localized pulses of electromagnetic energy that can travel through a medium and retain their spatiotemporal shape in spite of
diffraction and
dispersion
Dispersion may refer to:
Economics and finance
* Dispersion (finance), a measure for the statistical distribution of portfolio returns
*Price dispersion, a variation in prices across sellers of the same item
* Wage dispersion, the amount of variat ...
which tend to spread the pulse. This is made possible by a balance between the non-linear self-focusing and spreading effects brought about by the medium in which the pulse beam propagates.
Prediction and Discovery
Light bullets were predicted and so termed by Yaron Silberberg in 1990, and demonstrated the following decade.
Comparison with solitons
Spatial and temporal stability which are the characteristics of a
soliton
In mathematics and physics, a soliton or solitary wave is a self-reinforcing wave packet that maintains its shape while it propagates at a constant velocity. Solitons are caused by a cancellation of nonlinear and dispersive effects in the mediu ...
have been achieved in light bullets using alternative
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, o ...
models. An experiment which exploited the discrete spreading and self-focusing effects on 170-femtosecond pulses at 1550-nanometre wavelengths by a two-dimensional hexagonal array of silica waveguides reported a spatial profiles stationary for about twice as far as it would be in linear propagation and temporal profile about nine times stationary as that of the corresponding linear propagation.
Light bullets lose energy in the process of a
collision
In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word ''collision'' refers to incidents in which two or more objects collide with great fo ...
. This behavior is different from that of solitons which survive collisions without losing energy
Possible applications
* Artificially-induced lightning
* Monitoring air pollution
See also
*
Laser-induced breakdown spectroscopy (LIBS)
References
{{reflist
Electromagnetic radiation
Light
1992 in science