Author Affiliations
Abstract
1 College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, China
2 National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
3 State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China
This study investigated direct fluorescence generation from a nematic liquid crystal (NLC) NJU-LDn-4 under femtosecond laser excitation. The absorption, transmittance, excitation, and emission spectra of the NLC were assessed. The relationship between the femtosecond pump power and fluorescence intensity was analyzed, revealing a quadratic increase and indicating that two-photon absorption (2PA) is the primary fluorescence mechanism. The LC microstructure was designed using photoalignment technology, allowing the generated fluorescence to reflect the corresponding structure. This research can establish a foundation for tunable LC microstructured fluorescence, with potential applications in fluorescence microscopy and optoelectronics.
liquid crystal femtosecond laser fluorescence microstructure Chinese Optics Letters
2024, 22(3): 033801
1 南京邮电大学电子与光学工程学院,柔性电子(未来技术)学院,江苏 南京 210023
2 东南大学电子科学与工程学院,江苏 南京 210096
提出一种外泌体检测新方法,通过将表面增强拉曼散射(SERS)纳米探针固定在核酸适体(DNA)功能化水凝胶中,实现对肿瘤源性外泌体的高灵敏度光学检测。SERS纳米探针被用于识别肿瘤源性外泌体并产生指纹光学信号。SERS活性DNA功能化水凝胶(简称“SD水凝胶”)作为传感器,不仅提供了用于生物识别的三维反应位点,而且可放大SERS纳米探针的光学信号。选择性地与靶外泌体结合后,SERS纳米探针脱离SD水凝胶,导致SERS信号减弱,从而实现光学检测。通过SERS信号变化,SD水凝胶可以定量、灵敏地检测肿瘤源性外泌体,浓度检测限(LOD)约为22 μL-1。该SD水凝胶将为临床癌症诊断提供一种新的技术手段。
生物光学 表面增强拉曼散射光谱技术 光学检测 外泌体 纳米探针 水凝胶 光学学报
2023, 43(21): 2117001
Author Affiliations
Abstract
1 National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210023, China
2 College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, China
Controlling architecture of hierarchical microstructures in liquid crystals (LCs) plays a crucial role in the development of novel soft-matter-based devices. Chiral LC fingerprints are considered as a prospective candidate for various applications; however, the efficient and real-time command of fingerprint landscapes still needs to be improved. Here, we achieve elaborate rotational fingerprint superstructures via dual photopatterning semifree chiral LC films, which combine the photoalignment technique and a dynamic light patterning process. An intriguing spatial-temporal rotational behavior is presented during the patterning of chiral superstructures. This work opens new avenues for the applications of chiral LCs in soft actuators, sensing, and micromanufacturing.
liquid crystal photoalignment fingerprints chiral photoresponsive materials Chinese Optics Letters
2023, 21(4): 041603
Author Affiliations
Abstract
1 College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, China
2 National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210023, China
Electrically driven structural patterns in liquid crystals (LCs) have attracted considerable attention due to their electro-optical applications. Here, we disclose various appealing reconfigurable LC microstructures in a dual frequency nematic LC (DFNLC) owing to the electroconvection-induced distortion of the LC director, including one-dimensional rolls, chevron pattern, two-dimensional grids, and unstable chaos. These patterns can be switched among each other, and the lattice constants are modulated by tuning the amplitude and frequency of the applied electric field. The electrically switchable self-assembled microstructures and their beam steering capabilities thus provide a feasible way to tune the functions of DFNLC-based optical devices.
dual frequency liquid crystals pattern formation gratings diffractions Chinese Optics Letters
2023, 21(1): 010501
1 南京邮电大学电子与光学工程学院、柔性电子(未来技术)学院,江苏 南京 210023
2 南京大学现代工程与应用科学学院,江苏 南京 210023
向列相液晶因其独特的光学和电学各向异性,广泛应用于光电显示等领域。光通信技术的持续发展,需要液晶材料具有更快的电光响应。通过对6种负性向列相液晶施加垂直于分子平均取向的电场,结合特殊入射方式,系统地研究了电场对液晶取向涨落和单轴序参数的调控。实验结果表明:电光响应的开关时间均小于;液晶的介电各向异性越大,场致双折射率变化越大,其最大值与所施加的电场大小和向列相液晶的介电各向异性均呈线性关系。
光学器件 向列相液晶 介电各向异性 双折射率 序参数 取向涨落 电光开关 光学学报
2022, 42(21): 2123001
Author Affiliations
Abstract
1 College of Electronic and Optical Engineering and College of Microelectronics, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
2 National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
3 Collaborative Innovation Center of Advanced Microstructures & College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
4 Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA
Electric fields modify the optical properties of nematic liquid crystals (NLCs) by changing the nematic molecular orientation or order parameters, which enables electro-optic applications of NLCs. However, the field-induced optic change is undesirable in some cases. Here, we experimentally demonstrate that polymer stabilization weakens the birefringence change of NLCs caused by the nanosecond electrically modified order parameter effect. The birefringence change is reduced by 65% in the NLC doped with 25% reactive monomer, which is polymerized close to the nematic-to-isotropic phase transition. This technique could be used in liquid crystal devices where the birefringence change is unfavored.
liquid crystal electro-optical response birefringence polymerization Chinese Optics Letters
2022, 20(2): 023201
1 赣南师范学院物理与电子信息学院,江西 赣州 341000
2 赣南师范学院,江西 赣州 341000
3 赣南师范学院物理与电子信息学院
4 赣南师范学院光电子材料与技术研究所,江西 赣州 341000
基于ZnO纳米柱制备及发光实验,建立了ZnO纳米柱的位置和大小都是无序的二维介质结构模型.通过构建增益模型,用时域有限差分法数值模拟了无序介质中频谱特性以及ZnO增益频谱范围内的某一个共振峰对应的波源在无序介质中的光场分布情况,发现了局域模的存在.分四种情况讨论了此局域模的受激辐射与泵浦面积的关系:改变泵浦功率,从左到右依次增加两层ZnO纳米柱泵浦和单独泵浦一个局域区域; 泵浦功率一定时,增加泵浦局域区域和非局域区域中ZnO纳米柱个数.结果表明:存在一个临界泵浦功率,当泵浦功率小于临界泵浦功率时,无论泵浦面积多大都不能激发局域模; 当泵浦功率大于临界泵浦功率时,对于不同的泵浦功率,局域模被激发所需的临界泵浦面积不同; 随着泵浦功率的增加,当泵浦面积一定时,光场相对强度呈递增趋势,当泵浦功率超过临界功率时,光场相对强度急剧上升.
无序介质 局域模 泵浦面积 受激辐射 Random media Localized mode Pump sizes Stimulated emission
1 赣南师范学院物理与电子信息学院, 江西 赣州 341000
2 赣南师范学院光电子材料与技术研究所, 江西 赣州 341000
研究了以左手材料为衬底和单负材料为覆盖层三层平板波导中TE模的传输特性, 为波导器件的设计提供了理论支持。导出了归一化有效厚度与归一化频率的关系, 数值计算分析了三层平板波导的传输特性。结果表明,该三层平板波导TE模具有以下特性: 1)当导波 层与衬底或覆盖层磁导率的比值增大时,归一化有效折射率随频率的变化率减小。 2)当不 对称因子趋近于0时, 随单调变化;当较大时,在截止频率附近,TE、TE、TE、TE和TE模出 现双值现象。3)当增大时, -曲线从左向右移动。4)对于TE模, 出现负值。
纤维与波导光学 平板波导 左手材料 单负材料 传输特性 fiber and waveguide optics slab waveguide left-handed materials single-negative materials propagation properties