Gase Faraday Rotation Near The Absorption Edge

We measured the optical dispersion of the interband Faraday rotation of GaSe near the absorption edge at the temperature of 298°K. From our data it is possible to confirm that a direct allowed electronic transition takes place between the valence and the conduction bands in GaSe. © 1980 American Institute of Physics.72105341534

Verdet Constant Of Liquids; Measurements With A Pulsed Magnetic Field

The dispersion of the Verdet constant of several inorganic and organic liquids was measured at room temperature with a pulsed magnetic field in the spectral range from 0.3471 μm up to 0.6943 μm. We also measured the Verdet constant, at the wavelength of 0.4579 μm and at room temperature, of the three binary systems methanol-water, ethanol-water, and acetic acid-water. We found that the Verdet constant of mixtures is not additive. The deviation from additivity is positive for the three systems. © 1979 American Institute of Physics.71104021402

Oscillating Holograms Recorded In Photorefractive Crystals By A Frequency Detuned Feedback Loop

We report an optoelectronic feedback loop suitable for generating noise-free interference patterns oscillating at arbitrary waveforms. The technique allows controlling the frequency detuning between the interfering beams through a phase modulator in a closed-loop interferometer. We use the dither signal method and propose a quasisynchronous demodulation scheme to create a phase modulated error signal for driving the loop. The dynamics of the interference fringes is easily controlled by a voltage waveform from a function generator, which is used in association with a time delay circuit for shifting the frequency of the reference signal used for lock-in demodulation. The technique is specially suited for applications involving low-frequency phase oscillations, such as those frequently encountered in the generation of space-charge waves in highly resistive photorefractive materials. The processing scheme allows real time monitoring of the hologram strength, and absolute values for the diffraction efficiency and the holographic phase shift can be obtained. Photorefractive wave oscillations ranging from approximately 100 mHz to 10 Hz were produced in a nominally undoped Bi12 TiO20 sample. The technique can be readily applied to other fields of optical interferometry, such as for testing optical surfaces, optimizing adaptive holographic devices, measuring physical quantities, among other applications. © 2009 American Institute of Physics.1052Kukhtarev, N.V., Markov, V.B., Odoulov, S.G., Soskin, M.S., Vinetskii, V.L., (1979) Ferroelectrics, 22, p. 949. , 0015-0193Petrov, M.P., Stepanov, S.I., Khomenko, A.V., (1991) Photorefractive Crystals in Coherent Optical Systems, 59. , Springer Series in Optical Sciences Vol. (Springer-Verlag, Berlin)Huignard, J.P., Marrakchi, A., (1981) Opt. 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Mater. (Amsterdam, Neth.), 18, p. 99. , 0925-3467Bryushinin, M., (2004) Appl. Phys. B: Lasers Opt., 79, p. 851. , 0946-2171Bryushinin, M., Kulikov, V., Sokolov, I., (2005) Phys. Rev. B, 71, p. 165208. , 0163-1829 10.1103/PhysRevB.71.165208Freschi, A.A., Dos Santos, P.V., Frejlich, J., (2006) Appl. Phys. B: Lasers Opt., 83, p. 279. , 0946-2171Kamshilin, A.A., Frejlich, J., Cescato, L., (1986) Appl. Opt., 25, p. 2375. , 0003-6935Frejlich, J., Cescato, L., Mendes, G.F., (1988) Appl. Opt., 27, p. 1967. , 0003-6935Freschi, A.A., Frejlich, J., (1995) Opt. Lett., 20, p. 635. , 0146-9592Liu, J., Yamaguchi, I., Kato, J., Nakajima, T., (1997) Opt. Rev., 4, p. 216. , 1340-6000 10.1007/BF02931684Heilmann, R.K., Konkola, P.T., Chen, C.G., Pati, G.S., Schattenburg, M.L., (2001) J. Vac. Sci. Technol. B, 19, p. 2342. , 1071-1023 10.1116/1.1410096Moore, A.J., McBride, R., Barton, J.S., Jones, J.D.C., (2002) Appl. 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Analysis Of The Kinetics Of Phase And Amplitude Gratings Recorded In Azopolymer Films

In this work we use a stabilized holographic technique to study both refractive index and absorption gratings recorded in thin films made of Disperse Red 1 (DR1) embedded in an organic polymer matrix (PMMA) deposited on glass substrate. Gratings are recorded by linearly polarized illumination with the interference pattern of two crossing beams. One of the beams is phase modulated and the interference signals between the transmitted and diffracted waves are detected by a tuned lock-in amplifier. The technique allows measuring separately changes of the refractive index and the absorption coefficient during the course of the photoreaction process. The time evolution of the diffraction efficiencies during recording has shown bi-exponential kinetics for both gratings. © 2008 American Institute of Physics.992356360Sekkat, Z., Wood, J., Knoll, W., (1995) J. Phys. Chem, 99, pp. 17226-17234Taunaumang, H., Solyga, M., Tija, M.O., Miniewicz, A., (2004) Thin Solid Films, 461, pp. 316-324Blanche, P.-A., Lemaire, P.C., Maertens, C., Dubois, P., Jérome, R., (2000) Opt. Commun, 185, pp. 1-12Zhang, W., Bian, S., Kim, S.I., Kuzyk, M.G., (2002) Opt. Lett, 27 (13), pp. 1105-1107Frejlich, J., Kamshilin, A.A., Garcia, P.M., (1992) Opt. Lett, 17 (4), pp. 249-251Freschi, A.A., dos Santos, F.J., Rigon, E.L., Cescato, L., (2002) Opt. Commun, 208, pp. 41-4

Mössbauer studies of magnetic Fe2O3/SiO2 nanocomposites

Suppl. E (2006): Proceedings of the International Colloquium "Mössbauer Spectroscopy in Materials Science" (June 11–15, 2006, Kočovce, Slovak Republic)A large variety of glass and glass ceramics may be obtained by sol-gel process from hydrolysis of tetraethoxysilane. The transformation involves hydrolysis and polycondensation reactions leading to the growth of clusters that eventually collide together to form a gel. The structure and properties of the final product have been found to be strongly dependent on the initial conditions of preparation. Silica nanocomposites based on Fe2O3/SiO2 were prepared with the help of ultrasonic activation and subsequent annealing in nitrogen atmosphere or air with concentrations of iron oxide of about 20 to 30wt.%