共查询到20条相似文献,搜索用时 181 毫秒
1.
Manuel Ortuño Andrés Márquez Sergi Gallego Inmaculada Pascual 《Optics Communications》2008,281(6):1354-1357
Unslanted diffraction gratings are recorded in a 900 μm thick acrylamide photopolymer by means of peristrophic multiplexing. A solid state Nd:YAG (λ = 532 nm) laser is used as the recording beam, with a total incident intensity of 5 mW/cm2, and a He-Ne laser as the reconstruction beam. The dye concentration in the photopolymer is optimized so that it does not limit the dynamic range. Nine holograms are recorded using constant exposure time scheduling and variable exposure time scheduling. From the results obtained it may be deduced that optimization of the dye allows us to work in the linear response region of the photopolymer and at the same time obtain high values of diffraction efficiency for each hologram. An exponential increase in exposure time as the number of holograms increases enables the values of diffraction efficiency to be homogenized with regard to the case of constant exposure scheduling. In this way, better use is made of the dynamic range of acrylamide hydrophilic photopolymer. 相似文献
2.
New photopolymerizable holographic recording material based on polyvinylalcohol and 2-hydroxiethylmethacrylate (HEMA) 总被引:2,自引:0,他引:2
S. Blaya L. Carretero R.F. Madrigal M. Ulibarrena A. Fimia 《Applied physics. B, Lasers and optics》2002,74(6):603-605
We have developed a new polyvinylalcohol-based photopolymeric holographic recording material. The recording is obtained by
the copolymerization of acrylamide and 2-hydroxiethylmethacrylate (HEMA). Diffraction efficiencies near 70% are obtained with
exposures of ≈65 mJ/cm2 in materials of 110-μm thickness. The addition of HEMA increases the thickness of the film, which results in improved storage
capacity for holographic optical storage.
Received: 7 March 2002 / Published online: 2 May 2002 相似文献
3.
Mohesh Moothanchery Izabela Naydenova Vincent Toal 《Applied Physics A: Materials Science & Processing》2011,104(3):899-902
We studied the shrinkage in acrylamide-based photopolymer by measuring the Bragg detuning of transmission diffraction gratings
recorded at different slant angles and at different intensities. Transmission diffraction gratings of spatial frequency 1000
lines/mm were recorded in an acrylamide-based photopolymer film having 60±5 μm thickness. We have obtained the grating thickness
and the final slant angles from the Bragg curve and hence calculated the shrinkage caused by holographic recording. The shrinkage
of the material was evaluated for three different recording intensities 1, 5 and 10 mW/cm2, while the total exposure energy was kept constant at 80 mJ/cm2. From the experimental results it can be seen that the shrinkage of the material is higher for recording with lower intensities
and the corresponding values are 1.9%, 1.3% and 1%. 相似文献
4.
Andrejs Bulanovs Vjacheslavs Gerbreders George Kirilovs Janis Teteris 《Central European Journal of Physics》2011,9(5):1327-1333
As-S-Se chalcogenide thin films are successfully employed in classical and dot-matrix holography as inorganic photoresists
for obtaining a relief-phase hologram. However using these films for image-matrix hologram recording has not been studied
due to some features of image-matrix technology. For the applied research of the optical properties of As-S-Se films an experimental
device of digital image-matrix holographic recording based on 100 mW 405 nm semi-conductor laser and Spatial Light Modulator
(SLM) has been created. The device has the following main parameters: 140 × 105 μm frame size; laser intensity during exposure 10 W/cm2. With the help of this device diffraction grating and security holograms were recorded on As-S-Se thin films. The work reported
herein presents results of an experimental study of how diffraction efficiency (DE) of the received relief-phase holographic
gratings depends on an exposure and period. Diffraction grating profiles and speed of etching corresponding to different exposure
doses are shown. Hologram samples with DE = 65% have been received which allows for using chalcogenide film as alternative
to organic photoresists in applied dot-matrix and image-matrix holography. 相似文献
5.
Manuel Ortuño Elena Fernandez Sergi Gallego Augusto Beléndez 《Optics Communications》2006,268(1):133-137
The behaviour of a hydrophilic acrylamide photopolymer, with and without crosslinker (N,N′-methylene-bis-acrylamide), in solid layers 700 μm thick is analyzed. Slanted diffraction gratings are multiplexed at constant and variable exposure. Variable exposure time scheduling, with increased exposure time by steps is used in order to determine the effect on the dynamic range and the homogenization of diffraction efficiency values. This scheduling results in a greater dynamic range compared with constant time multiplexing. For crosslinked photopolymer, those exposure times are excessive (higher energetic sensitivity) and there is overlapping of the individual angular response curves for each stored diffraction grating. 相似文献
6.
V. V. Shelkovnikov E. V. Vasil’ev T. N. Gerasimova E. F. Pen A. I. Plekhanov 《Optics and Spectroscopy》2005,99(5):806-815
The dynamics of recording holographic diffraction gratings in photopolymer material using 10-ns pulses of Nd:YAG laser radiation (532 nm) was investigated. The formation of permanent and intermediate gratings was observed. Optimization of the photopolymer composition for pulsed recording was performed. The kinetic photopolymerization models taking into account the mechanisms of radical destruction due to recombination and by impurities are verified. Measurement of the recording kinetics at different recording angles showed that diffusion does not affect the hologram formation for times of the same order of magnitude as the recording duration (0.1 s) at a length of the grating half-period. Samples of the photopolymer composition in triethanolamine were investigated and diffusion of oligomeric acrylamide molecules was revealed. The diffusivity was found to be 1.1 × 10?9 cm2/s. 相似文献
7.
Hongpeng Liu Dan Yu Jian Wang Yongyuan Jiang Xiudong Sun 《Optics & Laser Technology》2012,44(4):882-887
The holographic recording and grating formation dynamics in SiO2 nanoparticle-dispersed PQ-PMMA photopolymer are investigated theoretically and experimentally. It has demonstrated a possibility to improve the refractive index modulation by doping inorganic nanoparticles into the polymer matrix. During exposure the nonlinear dependence γ of polymerization rate on the incident intensity is elevated and therefore faster grating formation rate is obtained in SiO2 nanoparticle-dispersed photopolymer. Mutual diffusion dynamics as dark diffusional enhancement mechanism after exposure is analyzed and simulated by mutual diffusion model. The maximum of mutual diffusion coefficient with the order of magnitude 10?16 m2/s is extracted. This study can provide a significant foundation for improving the properties of the polymer using inorganic nanoparticles as dopants. 相似文献
8.
Grating spacing dependence of nonvolatile holographic recording in doubly doped lithium niobate crystals is theoretically investigated allowing arbitrary charge transport lengths. It is shown that the nonvolatile refractive index modulation initially increases with increasing grating spacing, then a saturation behavior arises because of the dominant bulk photovoltaic effect. Although different charge transport length results in different nonvolatile refractive index modulation, the grating spacing dependence of nonvolatile holographic recording obeys almost the same rules for arbitrary charge transport lengths. The experimental results obtained by recording nonvolatile holograms in LiNbO3:Cu:Ce crystals with different grating spacing are consistent with the theoretical analyses. 相似文献
9.
10.
J. Vanhanen S. Parkkinen V. P. Leppanen T. Jaaskelainen J. P. S. Parkkinen 《Optical Review》2001,8(5):368-372
Holographic properties of a 13-demethyl retinal bacteriorhodopsin (13-demethyl BR) film in gelatin matrix were investigated and compared to those of a native bacteriorhodopsin (BRWT) film. A two-wave mixing experiment was performed to study the self-diffraction efficiency of the samples. The rise and the decay of the grating in the 13-demethyl BR film was measured. The film is relatively slow enabling the recording of simultaneous gratings. Phase conjugate reflectivity was measured by a four-wave mixing experiment. Diffraction efficiency and phase conjugate reflectivity of the 13-demethyl BR film were observed to be comparable to those of the BRWT film. 相似文献
11.
12.
The high-density holographic recording parameters of a novel two dyes-sensitized photopolymer under different exposure wavelengths are studied. The results show that the maximum diffraction efficiency, exposure sensitivity, maximum refraction index modulation, dynamic range, and the exposure time constant increases with the increase of the exposure wavelength. The analysis indicates that the scattering has an important role in the forming of the holographic grating. 相似文献
13.
C.Y. Liang Y.Y. Hung A.J. Durelli J.D. Hovanesian 《Journal of sound and vibration》1979,62(2):267-275
A new method is proposed for the determination of the in-plane displacement components of bodies subjected to cyclic loading. The recording on a photographic film is done statically, with exposure times longer than the period of vibration (time-average). A grating printed on the body surface is perturbed by the motion and the displacements are analyzed by photographing the grating lines. For relatively small amplitudes of vibration an alternative technique is proposed requiring the use of a master. Fringes are then photographed directly. In this case it is convenient to use a carrier which can be obtained by rotation of the master over the surface of the vibrating body. It is proposed to use Fourier filtering to convert frequency variation moiré fringes to the conventional intensity variation fringes. The application of the method is illustrated with the determination of u and ν components of displacement in a ring and in a disk subjected to cyclic diametral compression. As do other time-averaged methods, the proposed method has the advantage of permitting the static study of vibration phenomena. 相似文献
14.
Claus Jönsson 《Zeitschrift für Physik A Hadrons and Nuclei》1961,161(4):454-474
A glass plate covered with an evaporated silver film of about 200 å thickness is irradiated by a line-shaped electron-probe in a vacuum of 10?4 Torr. A hydrocarbon polymerisation film of very low electrical conductivity is formed at places subjected to high electron current density. An electrolytically deposited copper film leaves these places free from copper. When the copper film is stripped a grating with slits free of any material is obtained. 50 Μ long and 0·3 Μ wide slits with a grating constant of 1 Μ are obtained. The maximum number of slits is five. The electron diffraction pattern obtained using these slits in an arrangement analogous to Young's light optical interference experiment in the Fraunhofer plane and Fresnel region shows an effect corresponding to the well-known interference phenomena in light optics. 相似文献
15.
染料LB膜吸收光谱和光学存储效应的研究 总被引:1,自引:1,他引:0
通过对新型的染料LB膜(花氰-花生酸复合LB膜)的吸收光谱的测试,说明了LB膜中染料分子H-聚体结构的存在,而在立体简并四波混频实验中观察到这种LB膜具有可逆的光学记录与擦除效应,实验表明,在其中建立一个稳定的光栅,所用的记录光脉冲强度为30MW/cm~2,需要的累积记录时间为80ns(10个脉冲).最后在简化的三能级系统中,以分子处于各态的布居光栅模型说明了光致H-聚体,单体之间的转化是这种光学记录效应的主要原因. 相似文献
16.
光折变晶体均匀多重全息图存储研究 总被引:8,自引:3,他引:5
本文推导了光折变晶体角度编码多重全息存储中写入均匀光栅时的曝光时间递推公式.分析了散射效应对光栅写入时间常数的影响和写入光耦合对光栅振幅的影响,给出了两种因素影响下曝光时间计算的修正递推公式.数值计算结果表明,按照这种修正公式计算所得多重存储中各幅全息光栅振幅不仅均匀性好,而且振幅相对较大,这种曝光方法有利于提高晶体的存储容量.实验中以递推公式所得时间进行曝光记录,在厚度为0.6mm的Fe:LiNbO3晶体中采用角度编码很容易存储了30幅全息图. 相似文献
17.
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
18.
A. Emoto A. Tashima M. Kondo M. Okada S. Matsui N. Kawatsuki H. Ono 《Applied physics. B, Lasers and optics》2012,107(3):741-748
Anisotropic diffractive gratings formed by birefringent molecular alignment are fabricated by a holographic technique using a photo-cross-linkable liquid crystalline copolymer (PLCCP). Depending on the exposure energy used for holographic recording, bright or dark regions of the interference fringe can be chosen for the molecular-aligned region, analogous to positive- and negative-type photoresist processing in photolithography. In conjunction with simultaneously generated surface relief gratings, the anisotropic refractive index modulation inherent in the PLCCP film exhibits different diffraction properties depending on the incident beam polarization. The anisotropic refractive index grating profiles are quantitatively presented for two cases determined by the exposure energy, based on the Fourier analysis of diffractive optics. The selection of different grating formations selected by varying only the exposure energy could provide a strategy for the fabrication of functionalized diffractive optical elements. 相似文献
19.
Photopolymer systems can produce good image quality holograms that does not require any post-processing and are environmentally stable with good diffraction efficiency. The present work reports the development of a methylene blue-sensitized polyvinyl alcohol acrylamide (MBPVA/AA) photopolymer system for recording white light reflection holograms. Reflection gratings were recorded in the photopolymer films with different concentrations of methylene blue (MB). Various parameters affecting the holographic properties of the samples were also studied. The holographic performance of the material is found to depend on its chemical composition and the recording parameters. 相似文献
20.
A. Murciano S. Blaya L. Carretero M. Ulibarrena A. Fimia 《Applied physics. B, Lasers and optics》2005,81(2-3):167-169
In this paper, we present a photopolymerizable material in a sol-gel matrix suitable for recording a large number of multiplexed diffraction gratings with low total exposure energy. The matrix of this material is an inorganic porous silica glass, a material that does not shrink when radical photopolymerization is initiated. The photosensitive component is based on acrylamide, N,N′-methylenebisacrylamide, triethanolamine and yellow eosine as a photoinitiator. In the reported study, 50 holograms were angularly multiplexed with diffraction efficiencies between 0.1 and 1.9% resulting in a dynamic range of M/# = 3.9. The total exposure was 4.5 mJ/cm2 and the energy used in recording each hologram was 95 μJ/cm2. This indicates a very high sensitivity for this material in the range of 3.3 to 15.5 cm/mJ. Due to this good holographic performance, the material is suitable for holographic data storage applications. 相似文献