Interferometer Bragg

Fig. 1. The experimental set-up proposed to test neutrality of lithium atom is based on a Mach-Zehnder atom interferometer working in the Bragg configuration. Gi, G2, G3 are the three diffraction gratings and the detector is placed in front of one of the two complementary exits. The capacitor of length Lc extends from 2 = zm to z = zout-Some plates defining the zero potential in a symmetrical way are not represented...

Keywords Fiber- optic sensors Tilted fiber Bragg gartings (TFBG) Long-period gratings (LPG) LPG-based interferometers Chemical and biochemical sensing... 

Those based on the fluorescence lifetime, rather than intensity (e.g. the Ipitek system), allow one to avoid problems of light loss and other factors that could affect calibration, as discussed above. Assessment of tilted Bragg gratings and long-period gratings on optical fibres has shown them to be a probe of cure of the resin as well as being both temperature- and strain-sensitive (Buggy et al, 2007). The complexity of the response of these and fibre-optics based Fabry-Perot interferometers to strain, temperature and refractive index makes it necessary to employ combinations of sensors if measurements of all of these properties are required separately. 

Figure 19. Bragg-Grating-based tap/combiner (add/drop filter). Input signals (X4-X8) are coupled to Mach-Zender interferometers with Bragg grating. X4 is reflected to tap 2. All others exit through port 4.

A neutron reflectometer utilizes the optical phenomenon that neutrons incident on the material surface undergo refraction and reflection if the refractive indices on each side of the surface interface are different. A neutron interferometer using a perfect silicon crystal is analogous to the Mach-Zender interferometer of classical optics. The neutron wave amplitude coherently split by the Bragg reflection is superposed again at the second beam splitter and... 

Figure 4.18 Short-wavelength interferometer with top Bragg reflector using Oxide trapped between Polyl and Poly2. (Courtesy of Kevin Louchis and Benjamin Hemphill, Team Ninja Star in the Eye, EEl 15-Winter 2008, Final Report.)...

Bragg reffection occurs over a very narrow angle ( 10 rad) for perfect crystals. The degree of perfection determines the relative phases of beams generated by the X-ray interferometer. This sensitivity permits measurement of crystal strains as well as shifts caused by objects placed in the path. 

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