Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 308-312 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Decays of the diffraction efficiency of gratings written in Fe:LiNbO3 have been studied in connection with photorefractive fixing. Measurements have been carried at five different temperatures within the range of interest in photorefractive fixing, 144–168 °C. The decay curves are nonexponential and can be fitted to a sum of three simple exponential components, whose effective activation energies and preexponential factors have been determined. The dependence of the last exponential component on the grating period Λ has been measured and a 1/Λ2 law has been found. The decay constants have also been found to depend on the time the crystal is kept at the setting temperature before writing the grating. The difficulties for establishing a model taking into account the occurrence of several sites for protons in LiNbO3 are discussed. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 5146-5150 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A holographic method similar to that previously used with LiNbO3 to study the spectral behavior of photorefractive centers has been applied to Bi12SiO20 (BSO) and Bi12GeO20 (BGO). By erasing with incoherent light a previously written grating, measurements of the grating decay constants as a function of the erasing wavelength have been carried out. The grating erasure exhibits decays made up of a sum of two exponential terms for all wavelengths between 390 and 620 nm. In terms of recent photorefractive models which use two active species, our results imply that there exist two different photorefractive centers in BGO and BSO. By numerically fitting the observed spectral dependencies of the decay constants to the model equations, the absorption bands associated to these centers have been obtained. Their peak positions and half-widths are the following: 2.7 eV (0.27 eV) and 3.1 eV (0.4 eV) for BSO; 2.8 eV (0.3 eV) and 3.1 eV (0.4 eV) for BGO.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 2038-2041 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Pockel's electro-optic coefficients r31 and r33 of Li2B4O7 have been measured with an improved interferometric (Mach–Zehnder) method. The effective rc coefficient has also been measured by a polarimetric setup which, within the experimental error, has given the same value as that of the interferometric method. Attempts to measure the r42 coefficient with either the interferometric or the polarimetric method have given a value below the detection limit of our setups. All coefficients are given in terms of the published values of the piezoelectric coefficient d13. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 1287-1289 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: It is demonstrated that in optical waveguides formed by ion implantation in LiNbO3, the lower modes for the extraordinary index exist in a buried region of enhanced index, and so may be unable to couple with a surface prism. This is because a shallow region of slightly reduced index near to the surface necessitates the tunnelling of power to these "missing modes.'' The number of such modes can be inferred from a comparison of data for two different wavelengths, and confirmation of this together with an estimation of their positions may be obtained by surface stripping. By taking them into account it has been possible to model the profile index by using a stepped base to the optical well.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 994-997 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The ordinary and extraordinary refractive indices of rutile (TiO2) have been measured as a function of temperature and wavelength within the ranges 30–160 °C and 454–1330 nm, respectively, by using a prism coupling reflectivity setup. The measurements have been done with regard to the accurately known indices of a congruent LiNbO3 substrate. The index values are given with the same accuracy as that of the substrate taken as reference, i.e., ±0.001 at room temperature and ±0.003 at 160 °C. The room temperature values are coincident with those previously published by other workers. Sellmeier-like equations which include wavelength and temperature as variables within the studied ranges are given for both indices. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 2076-2078 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A method is described for producing high quality optical waveguides on Z-cut LiNbO3 substrates by proton exchange in pure benzoic acid vapor. Either α- or β-phase guides are obtained by varying the exchange temperature (within the 250–375 °C range) and/or the treatment duration (between 15 min and 24 h). The method presents definitive advantages with regards to common immersion methods. For both α- and β-phase guides the d33 nonlinear optical coefficient is 90% of the substrate value, and their optical losses are below 0.35 dB/cm. This is the first report on β-phase guides with almost undegraded nonlinear optical coefficients. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The third-order susceptibilities χ(3)(−3ω:ω,ω,ω) of Langmuir–Blodgett films of a series of octasubstituted metallophthalocyanines have been measured by third-harmonic generation experiments at 1.064 and 1.904 μm. For the latter excitation wavelength a marked enhancement of the nonlinearity for the cobalt-containing compound has been found, and χ(3) values are one order of magnitude larger than for the other systems. The effect has been associated to the role of two-photon allowed metal (possibly d−d) transitions in the cobalt derivative. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 60 (1992), S. 3212-3214 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A new method to determine the proton concentration in LiNbO3 is presented. The method is based on the measurement of the diffraction efficiency of a photorefractive grating in two situations. It is first measured after recording at room temperature, and second after saturation of the fixing process at a given temperature (about 150 °C). From only these two experimental data, the value obtained for the proton concentration in our sample is H0=(4.4±0.7)×1018 cm−3. This value agrees, within the experimental error, with that obtained from the infrared absorption arising from the OH− stretching bond.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 2468-2470 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A method is proposed and demonstrated to fabricate guiding layers on ordinary refractive index in proton exchanged LiNbO3 waveguides. The process consists of performing a reverse exchange in a melt very rich in lithium on a substrate previously exchanged in normal benzoic acid. Layers supporting several modes with ordinary polarization are easily obtained. Losses for these modes have been found to be below 0.7 dB/cm. Together with the increase of ordinary index, a decrease of the extraordinary one is obtained so that buried modes can be guided with this polarization. The influence on the reverse process of the exchange temperature, the substrate cut, and the melt composition is studied.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...