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Optical information medium

As previously mentioned, the evanescent wave could interact with the optically rare medium not only by being absorbed but also by being scattered either elastically (Rayleigh Scattering) or inelastically (Raman Scattering). Because it is not within the scope of this paper to review the complete history and theory of Raman scattering, further information is indicated in Ref. [Pg.253]

The interaction between the matter and the light beam is weak and I compute the state TOt using perturbation theory based on the complete set of exact states /> , with energies ha> of the chiral medium in the absence of the light beam, noting that the information yielded by the experiment can then be related to the optically active medium alone. The density matrix, , for the medium in the absence of the light beam can be given a spectral representation in terms of this complete set of states, by virtue of the spectral theorem,... [Pg.16]

J. Miyazaki, E. Ando, K. Yoshino, and K. Morimoto, Optical high density recording mediums, method for making same and method for recording optical information in the medium, U.S. Pat. 4,737,427, 8 pp., Apr. 12, 1988. [Pg.80]

An analysis of the properties of photochromic quinones shows that the main potential field of their applications is a light-sensitive medium for recording, multiplying, storing, and processing optical information. [Pg.307]

Presently, in order for optical information to be processed, the information must first be converted into electrical information before it can be operated upon by control electronics. Once the processing is complete, conversion to optical information is done before transmission. The transmission medium of today is optical (optical fiber) and the switching medium is electronic (integrated circuit). [Pg.401]

To summarize, we have studied the interaction of two weak quantum fields with an optically dense medium of coherently driven four-level atoms in tripod configuration. We have presented a detailed semiclassical as well as quantum analysis of the system. The main conclusion that has emerged from this study is that optically dense vapors of tripod atoms are capable of realizing a novel regime of symmetric, extremely efficient nonlinear interaction of two multimode single-photon pulses, whereby the combined state of the system acquires a large conditional phase shift that can easily exceed 1r. Thus our scheme may pave the way to photon-based quantum information applications, such as deterministic all-optical quantum computation, dense coding and teleportation [Nielsen 2000]. We have also analyzed the behavior of the multimode coherent state and shown that the restriction on the classical correspondence of the coherent states severely limits their usefulness for QI applications. [Pg.90]

If irradiation passes the interface from an optically denser medium to one of smaller refractive index, at angles larger than a certain limiting one (with respect to the perpendicular optical axis) the radiation will no longer leave the medium. It is totally reflected at the interface. Electrodynamics explain the fact that the reflected radiation couples to an evanescent field, which exponentially decreases into the medium of lower optical density. Thus the reflected beam gathers information about the optical properties of this medium across the interface. [Pg.286]

The setup for internal reflection spectroscopy is shown in Kg. 3. The electrode consists of a germanium reflection element, covered on one side with PPy in contact with the electrolyte solution. The IR beam is totally reflected at the interface between the reflection element and the PPy layer. The penetration depth of the IR beam into the optical thinner medium (polymer and electrolyte) at each total reflection is in the order of some m. Spectral information on this small region is available without disturbances by the bulk electrolyte. Since the counter electrode and the reference electrode can be mounted in an advantageous arrangement, no electrochemical hmitations, connected with a thin electrolyte layei occur using this method. Due to the limited stability of Ge in aqueous electrochemical systems, the water content of the electrolyte solution has to be very low. [Pg.403]

H. Horimai, Y. Sakane and K Kimura, "Optical information-recording medium, optical... [Pg.218]

Liu C, Dutton Z, Behroozi CH et al. Observation of coherent optical information storage in an atomic medium using halted light pulses. Nature (London) 2001 Jan 25 409 490-493. [Pg.126]

Another potential field of application for efficient SHG is optical information processing and routing. Currently, electrical cable as a medium for data transfer is being replaced by optical fiber, which allows much higher data transmission rates. [Pg.495]

When light traversing an optically dense medium approaches an interface with a more optically rare medium at an angle exceeding a critical value, Bent = sin (rerare/ dens), total internal reflection occurs and an evanescent wave of exponentially deca5ung intensity penetrates the rarer medium. This phenomenon is at the heart of certain spectroscopic methods used to probe biomolecules at interfaces (199). In total internal reflection fluorescence (TIRF) spectroscopy (200-202), the evanescent wave excites fluorescent probes attached to the biomolecules, and detection of the emission associated with their decay provides information on the density, composition, and conformation of adsorbed molecules. In fourier transform infrared attenuated total reflection (FTIR-ATIR) spectroscopy (203,204), the evanescent wave excites certain molecular vibrational degrees of freedom, and the detected loss in intensity due to these absorbances can provide quantitative data on density, composition, and conformation. [Pg.699]

In internal reflection, at angles of incidence larger than the critical angle, electromagnetic radiation is totally reflected (attenuated total reflectance, ATR. see Section 16.2.2.4 and Fig. 5). This special ca.se is very important in analysis for two approaches. First, simple transportation of radiation within the fiber (or a waveguide). Second, in total reflection, an evane.scent field appears in which the electrical field vector decays exponentially in the optically less dense medium. Every change within the medium with lower refractive index influences the field vector coupled to the field in the optically denser medium. Therefore, the totally reflected radiation contains information about effects on the other side of the phase boundary (the medium with lower refractive index) [20], [144]. Various principles to interogate this effect are known and used in evanescent field sensors. [Pg.448]

The other approach, internal reflection, takes advantage of the fact that if an electromagnetic wave is totally reflected at the interface between an optically thicker and an optically thinner medium (refraction index of the optical thicker medium is higher), a part of the electromagnetic wave penetrates into the optical thinner medium (the so-called evanescent wave) where it may interact with any species present and may be absorbed. The spectral intensity distribution of the reflected light thus differs from that of the incident beam and contains information about species present in the interphase of the optical thinner medium. In practical setups ATR (attenuated total reflection) single crystals are used, onto which the electrode under investigation is deposited. The beam baths of internal and external reflection are visualized in Fig. 1. [Pg.1072]

Jung, J. H. Lee, K. H. Yang, C. S. Synthesis and physical properties of cyanine dyes as optical information recording medium. J. Korean Chem. Soc. 1998, 42, 570-574. [Pg.156]

The medium used for the transmission of information and data over distances has evolved from copper wire to optical fiber. It is quite likely that no wire-based information transmission systems will be installed in the future. The manufacture of optical fibers, like that of microcircuits, is almost entirely a chemical process. [Pg.53]

It is therefore important to bear in mind the dependency of the carotenoid spectrum upon properties of the environment for in vivo analysis, which is based on the application of optical spectroscopies. This approach is often the only way to study the composition, structure, and biological functions of carotenoids. Spectral sensitivity of xanthophylls to the medium could be a property to use for gaining vital information on their binding sites and dynamics. The next sections will provide a brief introduction to the structure of the environment with which photosynthetic xanthophylls interact—light harvesting antenna complexes (LHC). [Pg.117]


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See also in sourсe #XX -- [ Pg.156 ]

See also in sourсe #XX -- [ Pg.143 , Pg.246 ]




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