Electromagnetic mirror

The atom mirror is the key element of matter-wave optics. An electromagnetic mirror for neutral atoms was suggested by Cook and Hill (1982). The idea was to use the radiation force of an evanescent laser wave outside a dielectric surface to repel slow atoms. This evanescent-wave atomic mirror was realized experimentally by Balykin et al. (1988a). 

This effect resembles the traditional Casimir effect, which describes the attraction between two parallel metallic mirrors in vacuum. Here, however, the fluctuating (bosonic) electromagnetic fields are replaced by fermionic matter fields. Furthermore, the Casimir energy is inferred from the geometry-dependent part of the density of states, and its sign is not fixed, but oscillates according to the relative arrangement and distances of the cavities. 

A double beam instrument splits the electromagnetic radiation into two separate beams, one for the reagent blank, and the other for the sample. There are two ways to do this. The first method uses a mirror that is half silvered and half transparent. As shown in Fig. 5.17 this results in a continuous beam of light for both the sample and reagent blank. 

The basic layout of a simple dispersive IR spectrometer is the same as for an UV spectrometer (Figure 2.1), except that all components must now match the different energy range of electromagnetic radiation. The more sophisticated Fourier Transform Infrared (FTIR) instruments record an infrared interference pattern generated by a moving mirror and this is transformed by a computer into an infrared spectrum. 

In essence, the explotron is a ducted sttucture optically coupled at one angle to a frangible optical member which is reflective to eleettomagnetic radiation and destructible by non-electromagnetic radiation. Upon actuation of the expl light source, the electro-rnaiifiptif radiation is directed bv a mirror to... 

An individual axisymmetric photon wavepacket that propagates in vacuo and meets a mirror surface, should be reflected in the same way as a plane wave, on account of the matching of the electromagnetic field components at the surface. Inside a material with a refraction index greater than that in vacuo, the transmission of the wavepacket is affected by interaction with atoms and molecules, in a way that is outside the scope of the discussion here. 

A simple thought experiment due to Einstein gives a basic idea of the interaction of electromagnetic radiation with matter. Consider a space surrounded on all sides by perfectly reflecting mirrors (Figure 2.9). Inside this cavity there is a hot material body which is in thermal equilibrium with the radiation which fills the cavity. This radiation is then isotropic, as it fills, in a random manner, all the space of the cavity its intensity can be defined as an energy per unit volume. 

A spectroscope is an instrument used to disperse a beam of electromagnetic radiation into its component waves. Many spectroscopes have diffraction gratings that separate the waves, which are beamed to a mirror and reflected back to the eye of an observer. Each wave appears as a separate colored line. 

A miniaturized Fourier transform spectrometer for near-infrared measurements (FTIR, 2500-8330 nm) was developed at the Forschungszentrum Karlsruhe [120], Near-infrared measurements give information, for example, about the oil, water and protein content of liquids or solids. The dimensions of the detector chip are 11.5 x 9.4 mm, the device is essentially a miniaturized Michelson interferometer and it consists of a micro optical bench with beamsplitter, ball lenses, mirrors and the detector chip. The light beam is coupled in via a glass-fiber and an electromagnetic actuator. The signal is derived from the signal response of the detector by Fourier transformation. 

Fig. 2. Schematic of the experimental arrangement. G is a diffraction grating, W a window, L a lens, Ml and M2 are mirrors, PC is a proportional counter, PM is a permanent magnet, and EMI and EM2 are electromagnets...

Interferometry exploits the superposition of electromagnetic waves to measure some physical property that probes the original state of the waves. Interferometers typically have light beams that are split by beam splitters (BS) (at least one per interferometer), reflected off mirrors, and measured by either one or two detectors. The path length difference and/or the phase difference are measured. 

---