1 Department of Physics, College of physics and Electronic Engineering, Northeast Petroleum University, Daqing 163318, Heilongjiang , China
2 Department of Physics, College of Electrical Engineering, Suihua University, Suihua 152000, Heilongjiang , China
We present a theoretical study of the one-dimensional modulational instability of a broad optical beam propagating in a biased photorefractive crystal with both linear and quadratic electro-optic effects (Kerr effect) under steady-state conditions. One-dimensional modulational instability growth rates are obtained by treating the space-charge field equation globally and locally. Both theoretical reasoning and numerical simulation show that both the global and local modulational instability gains are governed simultaneously by the strength and the polarity of external bias field and by the ratio of the intensity of the broad beam to that of the dark irradiance. Under a strong bias field, the results obtained using these two methods are in good agreement in the low spatial frequency regime. Moreover, the instability growth rate increases with the bias field, and the maximum instability growth occurs when ratio of light intensity to dark irradiance is 0.88.
nonlinear optics photorefractive effects spatial soliton modulational instability 激光与光电子学进展
2024, 61(5): 0519001
1 南开大学物理科学学院&泰达应用物理研究院，弱光非线性光子学教育部重点实验室，天津 300457
2 江苏科技大学理学院，江苏 镇江 212100
铌酸锂晶体是一种多功能、多用途的人工晶体材料，具有温度稳定性好、易于光学冷加工、性能易调控等优势。作为典型的光折变晶体，铌酸锂被广泛应用于高密度光存储、激光物理、信息处理和计算等研究与应用领域。伴随海量存储及动态全息三维显示的巨大需求与快速发展，基于铌酸锂晶体的三维光存储及动态显示再次成为研究热点。针对上述研究与应用，综述了铌酸锂晶体光折变全息存储及显示的原理、研究历史和最新进展，并对未来可能的发展方向进行了展望。
材料 铌酸锂晶体 光折变效应 全息存储 全息显示 中国激光
2023, 50(18): 1813001
Author Affiliations
Abstract
MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Institute of Applied Physics and School of Physics, Nankai University, Tianjin 300457, China
Holographic display has attracted widespread interest because of its ability to show the complete information of the object and bring people an unprecedented sense of presence. The absence of ideal recording materials has hampered the realization of their commercial applications. Here we report that the response time of a bismuth and magnesium co-doped lithium niobate (LN:Bi,Mg) crystal is shortened to 7.2 ms and a sensitivity as high as 646 cm/J. The crystal was used to demonstrate a real-time holographic display with a refresh rate of 60 Hz, as that of the popular high-definition television. Moreover, the first-principles calculations indicate that the electron mobility while Bi occupying Nb-site is significantly greater than that in Li-site, which directly induces the fast response of LN:Bi,Mg crystals when the concentration of Mg is above its doping threshold.Holographic display has attracted widespread interest because of its ability to show the complete information of the object and bring people an unprecedented sense of presence. The absence of ideal recording materials has hampered the realization of their commercial applications. Here we report that the response time of a bismuth and magnesium co-doped lithium niobate (LN:Bi,Mg) crystal is shortened to 7.2 ms and a sensitivity as high as 646 cm/J. The crystal was used to demonstrate a real-time holographic display with a refresh rate of 60 Hz, as that of the popular high-definition television. Moreover, the first-principles calculations indicate that the electron mobility while Bi occupying Nb-site is significantly greater than that in Li-site, which directly induces the fast response of LN:Bi,Mg crystals when the concentration of Mg is above its doping threshold.
holographic display lithium niobate photorefractive electron mobility Opto-Electronic Advances
2022, 5(12): 210135
南开大学物理科学学院&泰达应用物理研究院, 弱光非线性光子学教育部重点实验室, 天津 300457
铌酸锂(LiNbO3, LN)是一种多功能多用途的人工晶体, 被称为“光学硅”。近期以铌酸锂薄膜(LNOI)为平台的集成光子学发展迅速, 有将“光学硅”变为现实的趋势。高集成意味着高局域高光强密度, 使铌酸锂晶体的光折变效应变得不容忽视。光折变效应是光致折射率变化的简称, 是非线性光学的重要组成部分。本文回顾了铌酸锂晶体光折变效应的发现和机理、不同掺杂及掺杂组合对光折变效应的调控, 重点介绍了铋镁双掺铌酸锂晶体的光折变性能及相关理论和实验结果, 概述了铌酸锂光折变波导和孤子, 及基于LNOI的集成光子学器件中的光折变效应, 并对未来的研究趋势进行了展望。期待我国发挥铌酸锂光折变研究及LNOI产业化的优势, 在光子学芯片的竞争中占据主导地位。
铌酸锂晶体 光折变效应 机制 掺杂 全息存储及显示 集成光子学 lithium niobate crystal photorefractive effect mechanism doping holographic storage and display integrated photonics 人工晶体学报
2022, 51(9-10): 1626
重庆理工大学理学院绿色能源材料技术与系统重庆市重点实验室, 重庆 400054
本文提出一种基于半导体光放大器(SOA)光纤环形激光器的智能光纤动态应变传感系统,并采用自适应光折变双波混频技术对其进行解调,解调过程中无需对准静态应变和温度进行任何主动补偿。当FBG(Fiber Bragg Grating)传感器的反射光谱因动态应变而发生改变时,则激光输出的波长会相应移动,随后转换为相应的相移并由InP∶Fe光折变晶体双波混频干涉仪解调。实验结果表明,该传感系统能够测量50~464 kHz之间的动态应变且灵敏度高于0.5με Hz -1(ε为应变)。在InP∶Fe光折变晶体中同时对三个FBG传感器的动态应变进行解调,实验证实双波混频干涉仪的多路复用是切实可行的。
光学学报
2021, 41(13): 1306021
重庆理工大学理学院绿色能源材料技术与系统重庆市重点实验室, 重庆 400054
提出以单缺陷双边带非线性载流子输运方程描述InP∶Fe中光折变动态光栅的写入过程,通过微扰法将非线性方程线性化,从而求得小调制干涉图样下空间电荷场的稳态解,并用耦合波方程建立空间电荷场与增益系数的关系。研究温度、泵浦光强、外加直流电场和入射角对增益系数的影响。结果表明,增益系数存在温度-光强共振,最佳泵浦光强强烈依赖于晶体工作温度;施加直流电场对增益系数有明显提升作用,在10 kV·cm -1范围内增益随外加直流电场增加而线性增加;并且,在温度-光强共振条件下存在最佳入射角。在室温为298 K和外加电场为5 kV·cm -1时,最佳泵浦光强为218 mW·cm -2,最佳入射角为5°。通过InP∶Fe双波混频实验研究泵浦光强、外加直流电场和入射角对增益系数的影响,实验结果表明,增益系数变化规律与理论预测一致,验证了单缺陷双边带模型的合理性,该研究为Ⅲ-Ⅴ族半导体光折变晶体的双波混频研究提供重要的参考价值。
非线性光学 光折变材料 双波混频 空间电荷场 增益 外加电场 磷化铟 光学学报
2021, 41(12): 1219001
1 天津理工大学 理学院, 天津 300384
2 中原大学 理学院, 郑州 450007
在连续谱激光(532 nm)照射下, 观察到联苯衍生物有光折变现象。本文制备了(4-羟基苯基)-5-嘧啶醇、4′-羟基-4-联苯基腈、3-氨基-4-苯基苯酚和4, 4′-Biphenol两类实验样品, 将联苯衍生物分别溶于N, N-二甲基甲酰胺(DMF)溶剂中, 获得溶液浓度比为2wt%的4个溶液样品; 将联苯衍生物溶于无水乙醇通过常温慢速挥发, 制成了4个单晶体样品。在激光照射下, 2-(4-羟基苯基)-5-嘧啶醇、4′-羟基-4-联苯基腈和3-氨基-4-苯基苯酚3个溶液样品中观察到周期性对称的明暗相间的空间条纹。无论如何增大激光功率密度, 在4,4′-Biphenol溶液中, 都没有观察到类似的空间条纹。在强光功率密度照射下, 2 -(4-羟基苯基)-5-嘧啶醇、4′-羟基-4-联苯基腈、3-氨基-4-苯基苯酚3个单晶体出现光斑畸变, 同样在4, 4′-双酚单晶中没有观察到光斑畸变。在激光照射下或无光照射时, 测量到具有非对称基团的联苯衍生物样品的光电流与暗电流相差大约为10 nA。光斑畸变的伸长方向与激光的偏振态有关。在溶液和单晶样品中, 光斑畸变的光功率密度的阈值分别是100 W/cm2和10 W/cm2。上述实验结果可认为对称的周期性明暗空间条纹是由光折变效应引起的, 激光通过样品时, 由于联苯衍生物的极性分子受光电场的作用, 在光照区与非光照区产生空间电荷场, 由该空间电荷场引起样品折射率变化, 从而形成明暗相间的空间条纹。本文首次发现联苯衍生物是一种光折变材料。
光折变效应 空间条纹 空间电荷场 联苯衍生物 photorefractive effect spatial stripes space charge field biphenyl derivatives
采用分步傅里叶法,数值模拟研究了有偏压光伏光折变晶体中艾里高斯光束的传输特性.结果表明,当艾里高斯光束初始振幅和晶体的外加电场在一定范围内时,可以形成沿直线稳定传输的呼吸式孤子.调节初始振幅或外加电场可以控制孤子的峰值强度和呼吸周期.随着入射光场分布因子的变大,孤子的平均峰值强度先增大后减小,孤子的呼吸周期先变小后变大.随着光束衰减因子的增加,孤子的平均峰值强度先增大后减小,然后再增大.此外,光束入射角为负值时,孤子向左偏移,光束入射角为正值时,孤子向右偏移.入射角只改变孤子的输出位置,不影响孤子的强度、宽度和呼吸周期.
非线性光学 孤子 分步傅里叶法 光折变晶体 艾里高斯光束 Nonlinear optics Soliton Split-step Fourier method Photorefractive crystal Airy-Gaussian beams 光子学报
2019, 48(10): 1048004
