Title :
Characterization of PVK-based photorefractive polymers by photo-EMF technique in reflectance configuration
Author :
Stepanov, S. ; Pernas, V.C. ; Garcia, R.R. ; Mansurova, S. ; Meerholz, K. ; Gallego, F. ; Mecher, E. ; Bittner, R.
Author_Institution :
Instituto Nacional de Astrofisica, Opt. y Electron., Puebla, Mexico
Abstract :
Summary form only given. Characterization of photorefractive polymer films is a complicated problem because of the dependence of many relevant parameters, such as photocarrier generation rate, their life-time, and diffusion length, on the external field E/sub 0/. Especially difficult are investigations at low E/sub 0/ values, where holographic measurements are not reliable because of low diffraction efficiency. We report experimental data on characterization of a polymer film in photo-EMF configuration, which allows us to probe the space-charge grating even without application of the external field. Unlike similar dependence in photorefractive crystals (in BSO in particular) field dependence of the photo-EMF signal U/sup /spl Omega//(E/sub 0/) does not reach zero level exactly. We attribute this to proximity of /spl Omega/ used to one of the cut-off frequencies. Another explanation is the dispersion of all electrical parameters in amorphous systems.
Keywords :
carrier lifetime; diffraction gratings; photoconductivity; photorefractive materials; photovoltaic effects; polymer films; reflectivity; space charge; PVK-based photorefractive polymers; amorphous systems; cut-off frequencies; diffusion length; electrical parameter dispersion; external field; life-time; photo-EMF technique; photocarrier generation rate; reflectance configuration; space-charge grating; Character generation; Crystals; Diffraction; Gratings; Holography; Photorefractive effect; Photorefractive materials; Polymer films; Probes; Reflectivity;
Conference_Titel :
Lasers and Electro-Optics, 2002. CLEO '02. Technical Digest. Summaries of Papers Presented at the
Conference_Location :
Long Beach, CA, USA
Print_ISBN :
1-55752-706-7
DOI :
10.1109/CLEO.2002.1033941