Scientists demonstrated the fundamentally new source
radiation, which requires only heat, but it shines in a narrow band in the infrared region brighter than a blackbody. The device is based on photonic
crystals narrows the range of radiation, which in this luminosity
is more than eight times higher than that heated to the same temperature
body. The authors call this phenomenon Sverdlovsk radiation and believe that
it may find application in the field of conversion of dissipated heat in
useful energy, the system detecting objects in the dark and how bright a source in
optical research. The results were published in
Scientific Reports , and IEEE Photonics Journal.
There are various ways of generating electromagnetic
radiation. For example, laser and led light represents a fundamentally different
sources. However, the simplest option is thermal radiation of the heated
tel: in particular, the mechanism responsible for luminescence lamps
bulbs, candles and stars.
Heat radiation obeys Planck’s law, which
argues that completely absorbs all incident radiation the object (brand
black body) — is the most effective heat source, the range of which
is given by Planck’s formula and depends only on temperature. So no
the body is unable to Shine due to the heating is stronger than a black body with
the same temperature.
A black body is a physical abstraction and
the real body is not fully corresponds to it. However, the radiation of stars that
the number of the Sun, in a wide wavelength range well enough to the subject
the intensity of the wavelength derived in this approximation. As the principle of
the lasers and LEDs is not associated with the Planck formula and, generally speaking, with
temperature, these sources are not restricted to the limit of the blackbody.
Physicists from the United States and Canada under the leadership of Shawn-Yu Lin (Shawn-Yu
Lin) from the Polytechnic Institute Rensselaer has demonstrated a new type
generation of radiation. On the one hand, it is close to the heat, as it requires
only heating, but on the other — like a laser, so as the light only in a narrow band
of wavelengths centered on a 1.7 micron. Moreover, the first time scientists were able to show
the excess luminosity above the statutory limit in the Planck regime
the far zone, that is large compared to a wavelength distance from the
Created the device consists of a tungsten photonic
crystal, on top of which is an optical microcavities. Photon
crystal is a specific structure, a structure which allows you to manage
properties of photons. In this case it is as the photonic crystal used six layers of small bars of tungsten, which were located like
the atoms in the crystal lattice of the diamond.
For comparison of the luminosity photonic crystal with black body the authors
coated part of the sample with a layer of carbon nanotubes. It is known that the ordered nanotube
when observing from the end be very close to absolutely black body — they
absorb more than 99.9 percent of the incident radiation. The researchers measured the radiation power, fixing the sensor in several positions along one line, and in the first he recorded glow only covered nanotubes of the sample, and the latter only free from them. The measurement was carried out
in vacuum when heated to 575 K with a distance of 30 centimeters, or about
200 thousand wavelengths. The maximum excess over cerotelium emission is 8.3 times.