共查询到20条相似文献,搜索用时 62 毫秒
1.
Polarization holographic and surface-relief gratings have been recorded in an amorphous azobenzene polyester by use of a frequency-doubled argon-ion laser beam at 257 nm. Higher excited states of azobenzene in the trans and cis configurations contribute to the formation of a diffraction grating in this experiment. A combination of right and left circularly polarized writing beams has been found to give the highest diffraction efficiency. The contributions to the total phase difference that arise from anisotropy and surface relief have been separated experimentally, and it is shown that the surface-relief grating contributes a larger phase difference than that which is due to anisotropy. 相似文献
2.
利用偏振全息记录的方法在一种含偶氮侧链的液晶聚合物薄膜中写入了二维偏振光栅.实验采用两束正交偏振的532 nm线偏光作为写入光,在样品同一点上分别记录了相互垂直的两个一维偏振光栅,继而对所构成的二维偏振光栅的特性进行了研究.实验结果表明:二维光栅的衍射效率比一维光栅低,其偏振特性是两个一维光栅元特性的叠加;二维光栅衍射效率对入射光偏振态的依赖性和光栅的偏振转换性质来源于材料中线双折射和圆双折射的共同作用.
关键词:
偏振全息
二维光栅
偶氮液晶聚合物 相似文献
3.
Daisuke Sakai Kenji Harada Shun-ichi Kamemaru Daisuke Barada Fuminobu Sato Takashi Fukuda 《Optical Review》2009,16(3):335-338
We propose a method of hologram recording in a glass plate by corona charging. The holographic recording materials used in
this study are conventional soda-lime glass and azobenzene polymer film. A Fourier transform hologram on an azobenzene polymer
film coated on the glass plate is recorded in the glass plate by corona charging. After removing the polymer film, the hologram
recorded in the plate can be reconstructed using a visible-wavelength laser beam. The first-order diffraction efficiency of
the hologram at a wavelength of 532 nm is 0.03%; the efficiency depends on the depth of the surface relief structure on the
azobenzene polymer film and the corona-charging time. The hologram recorded in the glass plate has high environmental resistance. 相似文献
4.
We propose to utilize azobenzene as a nanomolecular switch which can be triggered by transmitting electrons above threshold biases. The effect is explained by an electron impact trans-cis conformational change of the isolated azobenzene molecules. The molecular electronic states of both isomers have been measured with spatially resolved scanning tunneling microscopy or spectroscopy, leading to suggested transition pathways of the electron-induced isomerization. 相似文献
5.
Holographic gratings were in a composite material that comprised a cross-linked polymer with azobenzene side chains and a nematic liquid crystal. Holographic recording was based on the photoinduced alignment of the nematic liquid crystal inside a cell as a result of amplification of the photoreorientation of azobenzene residues. The diffraction efficiency depends on cell thickness and reading angle of the gratings, so this composite material exhibits volume holographic properties with Bragg diffraction. 相似文献
6.
The microstructure of a poled surface-relief grating of an azobenzene side-chain polymer film is investigated. From the in situ monitoring of diffraction efficiency and second-harmonic generation, as well as dynamic-contact electrostatic force microscopy images, the point group symmetry of C2nu is identified. The polarization-dependent electro-optic measurement of the reflected diffraction order further confirms the optically biaxial structure of the poled surface-relief grating. 相似文献
7.
Polarization holographic recording was investigated in a liquid-crystalline azobenzene side-chain polymer. A highly stable
polarization holographic grating with the diffraction efficiency of 12.6% was written in the polymer film by two orthogonally
linearly polarized 532 nm beams with equal intensities of 150 mW/cm2. The polarization grating was studied with a 633 nm probe beam by surveying the conversion of the polarization state of the
probe beam and measuring the dependence of diffraction efficiency on the polarization direction of the probe beam. It was
found that the ± first-order diffraction efficiency and the polarization of the diffracted wave depended strongly on the polarization
of the readout wave. The unusual diffraction properties of the recorded grating were attributed to the presence of the circular
photoinduced birefringence.
PACS 42.40.Ht; 42.40.Lx; 78.20.Fm 相似文献
8.
根据衍射光栅的标量理论,计算并讨论了金透射光栅在软X波段衍射效率对光栅厚度和占宽比的依赖关系.结果表明,选择合适的光栅槽深和占宽比,高达 21.9%的衍射效率可能被获得,远高于振幅型光栅的+1级衍射效率10.14%.通过全息光刻与电镀转移技术制作的位相型金透射光栅由300nm的聚酰亚胺薄膜支撑,光栅槽深200nm,占宽比为0.55,周期为1μm,面积为20mm×5mm.在国家同步辐射装置上,测得其+1级透射衍射效率在波长λ=7.425nm时获得最大值,约为16%.
关键词:
透射位相光栅
全息光刻
电镀 相似文献
9.
10.
A.S. Rubanov 《Optics & Laser Technology》1996,28(4):301-309
The generation of dynamic holograms and four-wave phase conjugation in resonant media has been investigated under conditions of interaction between radiation and excited singlet and triplet states. Two mechanisms of optical control of resonant media non-linearities using independent pump-up to increase the diffraction efficiency of dynamic holograms have been considered. The peculiarities of non-linear recording of holograms, and a variant of quadratic recording, have been investigated. The dependence of the efficiency of diffraction by dynamic holograms on the intensity of interacting waves and the spectroscopic characteristics of the medium has been analysed. 相似文献
11.
多层介质膜光栅是高功率激光系统的关键光学元件.为了满足国内强激光系统的迫切需求, 在大口径多层介质膜光栅的研制过程中,建立了单波长自准直条件下的衍射效率测量方法及其误差分析. 结果表明误差主要由探测器的噪声和测试人员的差异产生,对衍射效率测试精度的影响是±1%. 在此基础上,将光栅衍射效率及其分布测量技术应用于光栅制作工艺中, 作为大口径光栅无损检测的一种手段,如判断光栅掩模是否能进行离子束刻蚀、 离子束刻蚀的在线监测和是否需要再刻蚀,从而实现对大口径多层介质膜光栅离子束刻蚀过程的定量、 科学控制,提高了离子束刻蚀光栅制作工艺的成功率.利用上述技术,已成功研制出多块最大尺寸为 430 mm× 350 mm、线密度1740线/mm、平均衍射效率大于95%的多层介质膜光栅. 实验结果表明,该方法操作简单、测量快速准确,不必检测光栅微结构. 为大口径多层介质膜光栅研制的无损检测工程化奠定了基础. 相似文献
12.
偶氮苯聚合物全息光栅衍射效率和偏振特性研究 总被引:1,自引:0,他引:1
研究了不同偏振全息模式下基于交联偶氮苯聚合物薄膜的相位光栅的形成机理、衍射效率和偏振特性.利用琼斯矢量表征了正交线偏振(SP)和半行线偏振(SS)干涉模式下的偏振干涉场.基于SP和SS两种模式,制作了无明显表成起伏的纯折射率光栅和有表面起伏的浮雕光栅.偏光显微镜(POM)观测说明纯折射率光栅具有周期性的折射率分布;近场光学显微镜(SNOM)探测说明纯折射率光栅和浮雕光栅的表而起伏在5 nm以下和 85.23 nm.实验表明.当探测光为水平偏振时,纯折射率光栅的衍射效率达到22.2%.浮雕光栅只能达到1.65%.纯折射率光栅的0、 1级衍射光分别为水平和竖直线偏振光,偏振度达到0.9969和0.9963;浮雕光栅的0, 1级衍射光均为水平线偏振光. 相似文献
13.
We investigate the persistent holographic recording in triply doped LiNbO3:Mn:Ce:Fe crystals at different oxidation/reduction states. The experimental results show that there is an optimum oxidation/reduction state, which results in the best dynamic range M/#. Compared with doubly doped LiNbO3:Ce:Fe, we found that the nonvolatile diffraction efficiency and the best dynamic range M/# obtained in triply doped samples are larger than that obtained in doubly doped samples. The reason for the increase of the crystal about the nonvolatile diffraction efficiency and the dynamic range M/# was also explained. 相似文献
14.
Tomoyuki Sasaki Masahiro Izawa Kohei Noda Emi Nishioka Nobuhiro Kawatsuki Hiroshi Ono 《Applied physics. B, Lasers and optics》2014,114(3):373-380
The formation of polarization holographic gratings with both optical anisotropy and surface relief (SR) deformation was studied for polymethylmethacrylate with azobenzene side groups. Temporal contributions of isotropic and anisotropic phase gratings were simultaneously determined by observing transitional intensity and polarization states of the diffraction beams and characterizing by means of Jones calculus. To clarify the mechanism of SR deformation, cross sections of SR were characterized based on the optical gradient force model; experimental observations were in good agreement with the theoretical expectation. We clarified that the anisotropic phase change originating in the reorientation of the azobenzene side groups was induced immediately at the beginning of the holographic recording, while the response time of the isotropic phase change originating in the molecular migration due to the optical gradient force was relatively slow. 相似文献
15.
Peculiarities of anisotropic acousto-optic Bragg diffraction in paratellurite by a slow acoustic wave have been considered. The ranges of frequency-angular dependences have been found, in which effective diffraction occurs, and their practical relevance has been formulated. The numerical values for light radiation with a wavelength of 1.06 μm have been obtained. We have proposed the method of enhancement of a diffraction efficiency of divergent optical radiation, which in turn leads to the increase of the response time of an acousto-optical modulator. The method is based on a multifrequency electric control of the acousto-optical modulator. We have shown experimentally that, as distinct from the single-frequency control, a considerable intensity suppression of the zero diffraction order from 30 to 8% is achieved. 相似文献
16.
Hunting for smectic C in calamitic azobenzene ionic liquid crystals with different cationic head groups
下载免费PDF全文
![点击此处可从《Journal of Physical Organic Chemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Nadia Kapernaum Eugen Wuckert Wolfgang Frey Sebastian Marino Manuel Wahl Frank Giesselmann Sabine Laschat 《Journal of Physical Organic Chemistry》2018,31(3)
The tilted smectic C phase is a rather uncommon phase in ionic liquid crystals (ILCs), whereas the orthogonal smectic A phase is the most common phase in ILCs. We now present 2 new groups of mesogens with an azobenzene core that exhibit smectic C as well as smectic A phases. Their phase sequences and tilt angles were studied by polarizing microscopy, and their temperature‐dependent layer spacings and orientational order parameters were investigated by X‐ray diffraction. We present 1 new amidinium azobenzene mesogen that forms enantiotropic smectic C and A phases and another amidinium as well as 2 new guanidinium azobenzene mesogens that exhibit monotropic smectic C and enantiotropic smectic A phases. With this study, we show that azobenzene is indeed an SmC‐promoting group in ILCs. Comparing these results with our earlier results on azobenzenes with an N‐methylimidazolium head group (N Kapernaum et al, ChemPhysChem 2016, 17, 4116‐4123), we show that the aromaticity of the imidazolium head group plays an important role in the formation of smectic C phases. 相似文献
17.
A model of the alignment of azobenzene molecules in polymer film induced by all-optical poling is proposed and verified by experiment. We found that when the writing beams of frequencies ω and 2ω are both linearly polarized with their polarization directions parallel to each other, azobenzene molecules tend to reorient to the direction perpendicular to the writing beams polarization. At the end of the writing process, more molecules orient to the direction perpendicular to the writing beams polarization than those which orient to the parallel direction. The alignment of molecules parallel or perpendicular to the polarization of the writing beams is characteristic of polarity or no polarity, respectively. The alignment of molecules along the polarization of writing beams results in the second order nonlinearity in the polymer film. According to the model, a new method to improve the optical poling efficiency is put forward. 相似文献
18.
Comstock MJ Levy N Kirakosian A Cho J Lauterwasser F Harvey JH Strubbe DA Fréchet JM Trauner D Louie SG Crommie MF 《Physical review letters》2007,99(3):038301
We have observed reversible light-induced mechanical switching for individual organic molecules bound to a metal surface. Scanning tunneling microscopy (STM) was used to image the features of individual azobenzene molecules on Au(111) before and after reversibly cycling their mechanical structure between trans and cis states using light. Azobenzene molecules were engineered to increase their surface photomechanical activity by attaching varying numbers of tert-butyl (TB) ligands ("legs") to the azobenzene phenyl rings. STM images show that increasing the number of TB legs "lifts" the azobenzene molecules from the substrate, thereby increasing molecular photomechanical activity by decreasing molecule-surface coupling. 相似文献
19.
借助于表面增强共振拉曼光谱散射(SERRS)技术,研究了一种新型的偶氮聚合物材料侧链含咔唑与偶氮分散红共聚物(CAP)在化学沉积法制备的银膜表面的拉曼峰增强和吸附行为。实验结果显示,CAP在银表面的状态为: 聚合物通过咔唑单体中咔唑基团和偶氮单体中硝基与银膜衬底发生物理吸附,而聚合物的主链与衬底相距较远没有相互作用。可以推测,聚合物在衬底表面的这种状态将对偶氮光存储器件的稳定性和工作效率产生不良影响。 相似文献