本文選題：鉭鈮酸鉀晶體　切入點(diǎn)：電光效應(yīng)　出處：《哈爾濱工業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：鉭鈮酸鉀晶體KTa_(1-x)Nb_xO_3(KTN)由于其在居里溫度附近具有很優(yōu)異的二次電光效應(yīng)而被廣泛地研究和應(yīng)用,被認(rèn)為是一種制備光學(xué)器件的優(yōu)異電光材料。對(duì)于KTN晶體在相界附近優(yōu)異電光性能的起源,目前廣泛認(rèn)為是由于相變過(guò)程中晶體內(nèi)部鐵電疇的影響。但對(duì)于KTN晶體中鐵電疇的觀察和其影響電光效應(yīng)的機(jī)理卻鮮有研究。本文主要研究了KTN晶體的電光性能對(duì)溫度與電場(chǎng)強(qiáng)度的動(dòng)態(tài)響應(yīng)特性,分析鐵電疇在相變溫度附近的演化過(guò)程,及其影響電光效應(yīng)的機(jī)理。研究了KTN晶體的基本物理性質(zhì)。采用電橋法測(cè)量了KTN晶體相對(duì)介電常數(shù)的溫度特性曲線,由介電反�，F(xiàn)象確定其居里溫度,從而得到了晶體的組分。由介電常數(shù)偏離居里外斯定律出發(fā),計(jì)算KTN晶體的弛豫因子,發(fā)現(xiàn)其在居里溫度附近具有一定的弛豫性,從側(cè)面驗(yàn)證在此特征溫度范圍內(nèi)鐵電疇的存在。測(cè)量了晶體的電滯回線,得到了矯頑場(chǎng)、自發(fā)極化強(qiáng)度等特征參量值,為極化處理和電光實(shí)驗(yàn)過(guò)程中外加電壓的范圍提供理論依據(jù)。研究了KTN晶體鐵電疇對(duì)溫度的動(dòng)態(tài)響應(yīng)。搭建Senamont單光束補(bǔ)償系統(tǒng)對(duì)極化完整的KTN晶體在升溫過(guò)程中的線性、二次電光系數(shù)進(jìn)行測(cè)量。將時(shí)域輸出電壓信號(hào)波進(jìn)行傅里葉變換,得到頻域信號(hào)波,分析居里溫度附近的電光效應(yīng)。利用偏光顯微鏡對(duì)鉭鈮酸鉀晶體的鐵電疇進(jìn)行了直接觀測(cè)。對(duì)比晶體極化處理前后、溫度升高和降低過(guò)程中晶體的偏光性,分析鐵電疇隨溫度的演化過(guò)程。研究了相界附近KTN晶體的鐵電疇對(duì)外加電場(chǎng)的動(dòng)態(tài)響應(yīng)。采用單光束補(bǔ)償法測(cè)量了相變附近晶體的電光系數(shù)隨電場(chǎng)強(qiáng)度的變化規(guī)律。設(shè)計(jì)實(shí)驗(yàn)并測(cè)量了在變化的交流電場(chǎng)下、變化的直流電場(chǎng)下的線性、二次電光系數(shù),并將極化前后的結(jié)果、不同溫度條件下的結(jié)果分別進(jìn)行對(duì)比。由唯象的朗道理論分析解釋了極化處理對(duì)鐵電疇的誘導(dǎo)取向和束縛效應(yīng),外加直流電場(chǎng)的場(chǎng)強(qiáng)和方向?qū)w鐵電疇重取向模式影響,揭示電光效應(yīng)的動(dòng)態(tài)響應(yīng)機(jī)制。
[Abstract]:The potassium tantalum niobate crystal KTaS _ 1-x _ X _ _ _. It is considered to be an excellent electro-optic material for the fabrication of optical devices. For the origin of the excellent electro-optic properties near the phase boundary of KTN crystal, At present, it is widely believed that the effect of ferroelectric domain in crystal is due to the influence of ferroelectric domain in the process of phase transformation. However, the observation of ferroelectric domain in KTN crystal and the mechanism of its influence on electro-optic effect are seldom studied. The electro-optic properties of KTN crystal are mainly studied in this paper. Dynamic response to temperature and electric field strength, The evolution process of ferroelectric domain near phase transition temperature and the mechanism of its influence on electro-optic effect are analyzed. The basic physical properties of KTN crystal are studied. The temperature characteristic curve of relative dielectric constant of KTN crystal is measured by bridge method. The Curie temperature of KTN crystal is determined by dielectric anomaly, and the composition of the crystal is obtained. The relaxation factor of KTN crystal is calculated from the deviation of dielectric constant from Curie's law, and it is found that it has certain relaxation property near Curie temperature. The existence of ferroelectric domains in this characteristic temperature range is verified from the side. The hysteresis loops of the crystals are measured, and the coercive field, spontaneous polarization intensity and other characteristic parameters are obtained. This paper provides a theoretical basis for the range of applied voltage in polarization processing and electro-optic experiments. The dynamic response of ferroelectric domains to temperature in KTN crystal is studied. The linearity of Senamont single-beam compensation system for polarized KTN crystals during heating process is built. The secondary electro-optic coefficient is measured. The time-domain output voltage signal wave is transformed by Fourier transform, and the frequency-domain signal wave is obtained. The electrooptic effect near Curie temperature is analyzed. The ferroelectric domain of potassium tantalum niobate crystal is observed directly by polarizing microscope. The evolution process of ferroelectric domain with temperature is analyzed. The dynamic response of ferroelectric domain of KTN crystal near phase boundary to external electric field is studied. The variation of electro-optic coefficient with electric field intensity is measured by single beam compensation method. Have been designed and measured in a variable alternating current field, The variation of the linear, secondary electro-optic coefficients under the DC field, and the results before and after polarization, The results are compared at different temperatures. The induced orientation and binding effect of polarization treatment on ferroelectric domains are analyzed and explained by phenomenological Landau theory, and the effect of the field strength and direction of the applied DC field on the reorientation mode of ferroelectric domains is explained. The dynamic response mechanism of electro-optic effect is revealed.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O614.113;O73

【參考文獻(xiàn)】

相關(guān)博士學(xué)位論文 前1條

1 王旭平;KTN系列晶體的生長(zhǎng)及其性能研究[D];山東大學(xué);2008年

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本文編號(hào)：1580237