For example, the refractive index of water is 1. Under normal conditions these values are constant as light travels through a substance. And this gives rise to what we call nonlinear optics. Let me show you some examples of what laser light can do and what this nonlinear optics stuff is!
The difference between these types of light is their size, or wavelength. Light waves vary in size from very long radio waves the size of a building, to very short gamma-rays smaller than the nucleus of an atom! Different sizes, or wavelengths, also mean different colors of light.
However, using high intensity light from a laser we can actually create light of a different size, or wavelength, than what we started with! Say we start with laser light that has a long wavelength of nanometers. This light is invisible to our eyes. If we focus this laser light through a special crystal, called a nonlinear crystal, we can actually produce blue light at nanometers! The fancy word for this is second harmonic generation, or frequency doubling.
We can turn invisible light into visible light! Crazy, I know! Well this illustrates that white light is actually made up of light of all sizes, long and short wavelengths, or all different colors. White light can be very useful when using lasers for scientific research. Luckily for us, we can use lasers to create white light from colored light! We can actually generate white light, or light consisting of a bunch of different sizes. So you start with light that has one wavelength and you can create white light, which contains a light of all different wavelengths!
All these crazy phenomena are possible because intense laser light can actually change the way a material interacts with light. The agreement of that curvature with the prediction of General Relativity was the first big piece of evidence for General Relativity.
However, the curvature near the Earth is much smaller even than near the Sun, because the Earth is very small compared to the Sun.
Really big curvature of light by gravity occurs near the strange objects called black holes, which were also predicted by General Relativity. So yes, the light ray from your laser will technically be bent by the earth's gravity. But no, the effect will not be enough to be noticeable. Is star light affected by a cluster of galaxies, or a cluster galaxy? The other unusual property is that of self-healing.
A limitation of the Florida work, however, is that Airy beams can only be bent through relatively small angles up to about 15 degrees.
This means that they cannot provide the sharp turns needed for manipulation on the micron or nanometre scale. A month later, two teams produced such beams in the lab — each bending light a degree arc.
Now, two independent teams have shown, both theoretically and experimentally, that non-paraxial acceleration along trajectories other than a circle is possible. In both cases, the groups were also able to bend the light through about 60 degrees. According to Berkeley group member Peng Zhang, these latest studies could lead to a number of practical applications.
These include particle manipulation and the burning of curved channels through air to guide plasmas for remote sensing. He also says they could be useful in medicine, allowing doctors, for example, to image or destroy a tumour behind an organ without destroying that organ.
In addition, Xiang Zhang says that the approach can be generalized to any other kind of wave system, such as matter waves, electron waves or acoustics. In fact, he points out, his group is investigating the bending of sound waves. He believes that it should be possible to transport sound energy around corners by manipulating the phase of acoustic waves with a device equivalent to a spatial light modulator.
This issue explores lasers and detectors, solar power, medical imaging and high-resolution displays. Close search menu Submit search Type to search.
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