{"title":"Spectroscopy of photorefractive centres in Bi12SiO20","authors":"J. Baquedano, J. M. Cabrera","doi":"10.1364/pmed.1990.b2","DOIUrl":null,"url":null,"abstract":"The spectroscopy of several centres in Bi12SiO20 which are related to its photorefractive behaviour will be presented and discussed. In a recent paper, the spectral dependence of the photorefractive erasure by using the holographic method has been studied [1]. Two major absorption bands producing photorefractive erasure were found, their peak positions and halfwidths respectively being 2.7 eV (0.27 eV) and 3.1 eV (0.4 eV). These bands were obtained by numerically fitting the experimental decay constants for each erasing wavelength to those predicted by a two centre model [2] in which fast carrier exchange between the two traps was assumed. Because of practical reasons related with the fitting process, the geometrical shadow effect (sample selfabsorption) was not taken into account in that paper. Therefore the band parameters obtained from photorefractive erasure are necessarily a first approximation which should be improved with other measurements. In this paper, an analysis of the optical absorption and photoconductivity spectra based in those gaussian components is presented. This analysis is expected to provide a more detailed knowledge of the bands responsible for the optical absorption, photoconductivity and photorefractiorn, although the actual nature of the centres originating the bands remains uncertain. Photochromic effects induced on these bands by low temperature illumination, as well as their thermal annealing, will be also considered.","PeriodicalId":385625,"journal":{"name":"Topical Meeting on Photorefractive Materials, Effects, and Devices II","volume":"80 6","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Topical Meeting on Photorefractive Materials, Effects, and Devices II","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1364/pmed.1990.b2","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The spectroscopy of several centres in Bi12SiO20 which are related to its photorefractive behaviour will be presented and discussed. In a recent paper, the spectral dependence of the photorefractive erasure by using the holographic method has been studied [1]. Two major absorption bands producing photorefractive erasure were found, their peak positions and halfwidths respectively being 2.7 eV (0.27 eV) and 3.1 eV (0.4 eV). These bands were obtained by numerically fitting the experimental decay constants for each erasing wavelength to those predicted by a two centre model [2] in which fast carrier exchange between the two traps was assumed. Because of practical reasons related with the fitting process, the geometrical shadow effect (sample selfabsorption) was not taken into account in that paper. Therefore the band parameters obtained from photorefractive erasure are necessarily a first approximation which should be improved with other measurements. In this paper, an analysis of the optical absorption and photoconductivity spectra based in those gaussian components is presented. This analysis is expected to provide a more detailed knowledge of the bands responsible for the optical absorption, photoconductivity and photorefractiorn, although the actual nature of the centres originating the bands remains uncertain. Photochromic effects induced on these bands by low temperature illumination, as well as their thermal annealing, will be also considered.
本文将介绍和讨论Bi12SiO20中与其光折变行为有关的几个中心的光谱。本文研究了全息法光折变擦除的光谱依赖性。发现产生光折变擦除的两个主要吸收带,其峰位和半宽分别为2.7 eV (0.27 eV)和3.1 eV (0.4 eV)。这些波段是通过数值拟合每个擦除波长的实验衰减常数与假设两个陷阱之间快速载流子交换的双中心模型[2]预测的结果得到的。由于与拟合过程有关的实际原因,本文没有考虑几何阴影效应(样本自吸收)。因此,从光折变擦除得到的带参数必然是第一近似,并应通过其他测量加以改进。本文给出了基于高斯分量的光吸收光谱和光电导光谱的分析。这一分析有望提供对负责光吸收、光电导率和光折射的能带的更详细的知识,尽管产生能带的中心的实际性质仍然不确定。低温光照对这些能带的光致变色效应,以及它们的热退火,也将被考虑。