發(fā)布時間：2018-03-07 17:24

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

【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)異的二次電光效應而被廣泛地研究和應用,被認為是一種制備光學器件的優(yōu)異電光材料。對于KTN晶體在相界附近優(yōu)異電光性能的起源,目前廣泛認為是由于相變過程中晶體內部鐵電疇的影響。但對于KTN晶體中鐵電疇的觀察和其影響電光效應的機理卻鮮有研究。本文主要研究了KTN晶體的電光性能對溫度與電場強度的動態(tài)響應特性,分析鐵電疇在相變溫度附近的演化過程,及其影響電光效應的機理。研究了KTN晶體的基本物理性質。采用電橋法測量了KTN晶體相對介電常數的溫度特性曲線,由介電反�，F象確定其居里溫度,從而得到了晶體的組分。由介電常數偏離居里外斯定律出發(fā),計算KTN晶體的弛豫因子,發(fā)現其在居里溫度附近具有一定的弛豫性,從側面驗證在此特征溫度范圍內鐵電疇的存在。測量了晶體的電滯回線,得到了矯頑場、自發(fā)極化強度等特征參量值,為極化處理和電光實驗過程中外加電壓的范圍提供理論依據。研究了KTN晶體鐵電疇對溫度的動態(tài)響應。搭建Senamont單光束補償系統(tǒng)對極化完整的KTN晶體在升溫過程中的線性、二次電光系數進行測量。將時域輸出電壓信號波進行傅里葉變換,得到頻域信號波,分析居里溫度附近的電光效應。利用偏光顯微鏡對鉭鈮酸鉀晶體的鐵電疇進行了直接觀測。對比晶體極化處理前后、溫度升高和降低過程中晶體的偏光性,分析鐵電疇隨溫度的演化過程。研究了相界附近KTN晶體的鐵電疇對外加電場的動態(tài)響應。采用單光束補償法測量了相變附近晶體的電光系數隨電場強度的變化規(guī)律。設計實驗并測量了在變化的交流電場下、變化的直流電場下的線性、二次電光系數,并將極化前后的結果、不同溫度條件下的結果分別進行對比。由唯象的朗道理論分析解釋了極化處理對鐵電疇的誘導取向和束縛效應,外加直流電場的場強和方向對晶體鐵電疇重取向模式影響,揭示電光效應的動態(tài)響應機制。
[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.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O614.113;O73

【參考文獻】

相關博士學位論文 前1條

1 王旭平;KTN系列晶體的生長及其性能研究[D];山東大學;2008年

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本文編號：1580237