Fabry optical

A Ge Ga photoconductive detector at lOOym and a GaAs epitaxial photoconductive detector at 285ym has been optimized for sensitivity comparison with a conventional bolometer system of Yerkes Observatory. The response of the photoconductive detectors were studied in the laboratory under two background conditions baffles and Fabry Optics. A direct comparison of the photoconductive detectors to the bolometer will be made on the 91.5 cm telescope aboard the NASA C-141 Airborne Infrared Observatory. 

The advent of lasers allowed optical interferometry to become a useful and accurate technique to determine surface motion in shocked materials. The two most commonly used interferometric systems are the VISAR (Barker and Hollenbach, 1972) and the Fabry-Perot velocity interferometer (Johnson and Burgess, 1968 Durand et al., 1977). Both systems produce interference fringe shifts which are proportional to the Doppler shift of the laser light reflected from the moving specimen surface. Both can accommodate a speci-... 

Figure 3.10. Fabry-Perot fringe records of a moving reflector. Comparison of the two different records suggest superior fringe signals when optical fibers are used to transmit light signals (Gidon et al., 1984).

Durand, M. (1984), Use of Optical Fibers for Velocity Measurement by Laser Doppler Interferometry with a Fabry-Perot Interferometer. In High Speed Photography and Photonics, Proc. SPIE, 491 (edited by M. Andre and M. Hugenschmidt), pp. 650-656. 

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. 

Jerman, J. H., and D. ]. Clift. Miniature Fabry-Perot Interferometers Micromachined in Silicon for the Use in Optical Fiber WDM Systems. Transducers 91 Conference, Digest of Technical Papers (1991), pp. 372-375. 

We have seen how the presence of shot noise dictates some key choices minimum laser power, beam and mirror diameter, necessity to use Fabry-Perot cavities in the arms. Other noise sources will fix other important optical parameters. 

At 10Hz in a typical Nd-YAG laser 1000Hz/- /Hz, and the typical finesse asymmetry is of the order of one percent. In order to detect a gw signal the laser frequency noise has to be lowered by six orders of magnitudes (compared to the noise of a free running laser), and the two arms made as identical as possible. In order to achieve this complex frequency stabilization methods are employed in all interferometric detectors, and in order to insure the perfect symmetry of the interferometer, all pairs of Virgo optical components are coated during the same run (both Fabry-Perot input mirrors then both end mirrors are coated simultaneously). 

The surface forces apparatus (SEA) can measure the interaction forces between two surfaces through a liquid [10,11]. The SEA consists of two curved, molecularly smooth mica surfaces made from sheets with a thickness of a few micrometers. These sheets are glued to quartz cylindrical lenses ( 10-mm radius of curvature) and mounted with then-axes perpendicular to each other. The distance is measured by a Fabry-Perot optical technique using multiple beam interference fringes. The distance resolution is 1-2 A and the force sensitivity is about 10 nN. With the SEA many fundamental interactions between surfaces in aqueous solutions and nonaqueous liquids have been identified and quantified. These include the van der Waals and electrostatic double-layer forces, oscillatory forces, repulsive hydration forces, attractive hydrophobic forces, steric interactions involving polymeric systems, and capillary and adhesion forces. Although cleaved mica is the most commonly used substrate material in the SEA, it can also be coated with thin films of materials with different chemical and physical properties [12]. 

Nineteen women underwent amniocentesis for the determination of fetal sex. Several different X-llnked abnormalities constituted the Indications for this procedure, and these Included hemophilia A, hemophilia B, Duchenne muscular dystrophy, optic albinism, X-llnked mental retardation, the Lesch-Nyhan syndrome (due to dlflclency of hypoxanthlne-guanlne phosphorlbosyltransferase, and Fabry s disease (due to deficiency of an a-galact-osldase). Fourteen of the fetuses were male. Including one which turned out to be a set of twins, and most of the male pregnancies were terminated. The sex determination being carried out for Fabry s disease Is of particular Interest, since In this case It was desired to find out whether the fetus was a female. 

Mitchell G.L., A review of fabry-perot Interferometric sensors, in Optical Fiber Sensors, Proc.6th Int.Conf. OFS 89 (1989), H.J.Arditty, J.P.Dakin, R.ThKersten eds., Springer-Verlag, pp. 450-478. 

Xiao, G. Z. Adnet, A. Zhang, Z. Sun, F. G. Grover, C. P., Monitoring changes in the refractive index of gases by means of a fiber optic Fabry Perot interferometer sensor, Sens. Actuators A Phys. 2005, 118, 177 182... 

Bhatia, V. Murphy, K. A. Claus, R. O. Jones, M. E. Grace, J. F. Tran, T. A. Greene, J. A., Optical fiber based absolute extrinsic Fabry Perot interferometric sensing system, Meas. Sci. 

Zhang, Y. Shibru, H. Cooper, K. L. Wang, A., Miniature fiber optic multicavity Fabry Perot interferometric biosensor, Opt. Lett. 2005, 30, 1021 1023... 

Ran, Z. L. Rao, Y. J. Liu, W. J. Liao, X. Chiang, K. S., Laser micromachined Fabry Perot optical fiber tip sensor for high resolution temperature independent measurement of refractive index, Opt. Express 2008, 16, 2252 2263... 

Cox, E. R. Jones, B. E. Fiber optic color sensors based on Fabry Perot interferometry, In First International Conference on Optical Fiber Sensors, London, 1993... 

Previously, Goddard and co-workers used anti resonant Fabry Perot reflectors to form antiresonant reflecting optical waveguides (ARROWs) in a gel layer13 14. 

To demonstrate the method an example of a slow-wave optical structure is modelled. Such structures consist of a cascade of directly coupled optical resonators in order to enhance the nonlinear effects. The structure used here was recently defined within Working Group 2 of the European Action COST Pll (http //w3.uniromal.it/energetica/slow waves.doc). One period of the structure consists of one-dimensional Fabry-Perot cavity placed between two distributed Bragg reflectors (DBR) and can be described by the sequence... 

Enhancement of the Hght-matter interaction in a microscopic optical cavity is achieved because Hght trapped in the cavity has longer effective interaction time with absorbers. For short laser pulses, cavity length exceeding CTp allows avoidance of the interference between the pulses incident and reflected from the mirrors. Spectral selectivity of planar Fabry-Perot cavities can be used to achieve the localization at the resonant wavelength of the cavity. 

Let us consider an optical system with two modes at the frequencies oo and 2oo interacting through a nonlinear crystal with second-order susceptibility placed within a Fabry-Perot interferometer. In a general case, both modes are damped and driven with external phase-locked driving fields. The input external fields have the frequencies (0/, and 2(0/,. The classical equations describing second-harmonic generation are [104,105] ... 

Let us consider a quantum optical system with two interacting modes at the frequencies coi and ff>2 = respectively, interacting by way of a nonlinear crystal with second-order susceptibility. Moreover, let us assume that the nonlinear crystal is placed within a Fabry-Perot interferometer. Both modes are damped via a reservoir. The fundamental mode is driven by an external field with the frequency (0/ and amplitude F. The Hamiltonian for our system is given by [169,178] ... 

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