Wavelength infrared

It is usually possible to investigate very thin films (up to the subnanometer range) by use of infrared wavelengths, which are much greater than the thickness of the film (a factor of 10000) because of the interference optics of the strong oscillator (Berreman effect). 

CBCF for infrared wavelength from 2 to 55 im is eompared with that of etched beryllium in Fig. 10. The data show that the CBCF is uniformly light absorbing up to at least 50 pm, in marked contrast to the etched beryllium light absorber which effectively absorbs wavelengths only up to about 20 pm. 

Fabry-Perot interferometer is an optical resonator consisting of two parallel mirrors. Fabry-Perot interferometers can be made by silicon bulk microma-chining." " Silicon surface micromachining is also a suitable technique for making interferometers for infrared wavelengths. 

In the preceding discussion of Beer s Law, it was argued that x-ray absorption is a simpler process than the absorption of ultraviolet, visible, and infrared wavelengths. This greater simplicity becomes particularly obvious when x-ray absorption coefficients are examined. 

Now we describe metallic layer coatings, which are widely used in astronomy. Gold is slightly better at infrared wavelengths than silver. At short wavelengths aluminum is by far the best of the 3 metals (Fig. 13), but with a marked minimum around 800 nm. The driving parameter is the thermal conductivity. 

Meteorites on Mars. Meridiani Planum is the first Iron meteorite discovered on the surface of another planet, at the landing site of the Mars Exploration rover Opportunity [359]. Its maximum dimension is 30 cm (Fig. 8.38). Meteorites on the surface of solar system bodies can provide natural experiments for monitoring weathering processes. On Mars, aqueous alteration processes and physical alteration by Aeolian abrasion, for example, may have shaped the surface of the meteorite, which therefore has been investigated intensively by the MER instruments. Observations at mid-infrared wavelengths with the Mini-TES... 

The atoms in molecules can be regarded as behaving like two spheres connected by a spring, with a natural vibration frequency. It so happens that the vibrations of atoms tend to correspond to an energy equivalent to a wavelength in the mid-infrared. It would appear that mid-infrared wavelengths would be useful for measuring the quantity of substances in systems like flour. In practice that is not so. Infrared peaks have a lot of... 

K. Uludag, M. Kohl, J. Steinbrink, H. Obrig, and A. Villringer. Cross talk in the lambert-beer calculation for near-infrared wavelengths estimated by monte carlo simulations. Journal of Biomedical Optics, 7(l) 51-59, 2002. 

Light scattering by the sample can cause correctable (14) errors in photoacoustic spectra, particularly at visible amJ shorter wavelengths. However, at mid-infrared wavelengths this is no longer an Important consideration. 

The trace gases in the earth s atmosphere are only a few percent of its composition but they make the planet livable. They absorb radiant energy at infrared wavelengths much more efficiently than they absorb radiant energy at solar wavelengths, thus trapping most of the radiant heat emitted from the earth s surface before it escapes. 

Painter, O.J., Husain, A., Scherer, A., O Brien, J.D., Kim, L, and Dapkus, P.D., 1999, Room temperature photonic crystal defect lasers at near-infrared wavelengths in InGaAsP, J. Lightwave Technol. 17(ll) 2082-2088. 

The major absorbers of infrared radiation in the atmosphere are HjO, CO2, and O3. The infrared wavelength ranges of 2-2.5 pm, 3-5 pm, and 8-12 pm are known as atmospheric windows. The radiative energies transmitted from the Sun to the Earth s surface within these atmospheric windows are shown in Table 12.3. 

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