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1.
Dynamic analysis of holographic gratings in amulti-wavelength visible light sensitive photopolymer
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A dynamic theoretical model of photochemistry and
hologram formation in holographic photopolymer is established, and
the dynamic development process of holographic gratings in the
photopolymer is discussed with the model. A novel multi-wavelength
visible light sensitive photopolymer for holographic storage is
prepared. The influence of exposure wavelength on holographic
storage characteristics is analysed. By fitting the experimental
data of transmittance and diffraction efficiency to a function of
time with different exposure intensities and wavelengths, the
variations of dynamic parameters of photochemistry and
photopolymerization diffusion are presented. 相似文献
2.
Bragg gratings are used in several photonic devices to reflect, and thus to isolate, specific wavelengths of light. Gratings can be photoinduced in chalcogenide glasses by illumination of bandgap light in an interference pattern. We used holographic interferometry to create Bragg gratings in amorphous As2Se3 thin films with a period of 0.56 microm by illumination with 633-nm light. The quality of the gratings was tested in real time, and refractive-index modulations as high as 0.037 were measured. These gratings were found to be stable over a period of several months if they were kept in the dark. 相似文献
3.
本文叙述了全息光栅的制造原理、工艺要求和制造技术。介绍了平场全息光栅、图象全息光栅、超环面全息光栅、激光全患光栅和闪耀全息光栅的新进展。最后,作者提出进一步发展全息光栅的若干建议。 相似文献
4.
Geary K. Schwemmer Richard D. Rallison Thomas D. Wilkerson David V. Guerra 《Optics and Lasers in Engineering》2006,44(9):881
We have developed and investigated the use of holographic optical elements (HOEs) and holographic transmission gratings for scanning lidar telescopes. Rotating a flat HOE in its own plane with the focal spot on the rotation axis makes a very simple and compact conical scanning telescope. We developed transmission and reflection HOEs for use at the first three harmonic wavelengths of Nd:YAG lasers. The diffraction efficiency, diffraction angle, focal length, focal spot size and optical losses were measured for several HOEs and holographic gratings, and found to be suitable for use as lidar receiver telescopes, and in many cases could also serve as the final collimating and beam steering optic for the laser transmitter. Two lidar systems based on this technology have been designed, built, and successfully tested in atmospheric science applications. This technology will enable future spaceborne lidar missions by significantly lowering the size, weight, power requirement and cost of a large aperture, narrow field of view scanning telescope. 相似文献
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In this paper, we present an approach to measure the refractive index modulation of volume phase holographic gratings (VPHG) by use of its angular selectivity, with the advantage of avoiding the diffraction efficiency errors induced by noise. Based on Kogelnik's coupled wave theory for volume holographic gratings, the wave vectors matching relationship for reflective VPHG at different readout wavelengths is deduced and the diffraction efficiency as a function of readout angle is also obtained. Then an all-fiber experimental system is designed to measure corresponding diffraction efficiency with different readout angles for VPHG recorded in dichromate gelatin. By seeking the Bragg angle where diffraction efficiency is maximum and the blank angle where diffraction efficiency drops to the minimum value, the refractive index modulation can be calculated. The experiment results proves the feasibility of the method. 相似文献
7.
高质量全息光栅实验系统研究 总被引:2,自引:1,他引:1
基于全息光栅在信息光学及光谱仪中的重要地位,对全息光栅进行了理论分析,提出了一种新的制作高质量全息光栅的实验系统.该实验系统的优点在于:将激光器发出的高斯光束改造成为均匀平面光波,以此平面光波作为光源可以制作出高质量的全息光栅. 相似文献
8.
The diffraction properties of reflection volume holographic gratings are studied when the gratings are illuminated by an ultrashort beam with arbitrary temporal profiles. The modified Kogelnik's theory of coupled waves is used. Simple analytical expressions for spectral and temporal distribution of the transmitted and diffracted are obtained. The dependences of the diffraction bandwidth, the Bragg selectivity bandwidth and the total diffraction efficiency of the reflection volume grating on the temporal profiles of the input ultrashort pulse are investigated. Study shows that the bandwidth of the reflection volume holographic gratings varies with the grating parameters more slowly than the transmitting volume holographic gratings. For three different temporal profiles, numerical results about diffraction properties of the reflection volume holographic gratings are given and compared with the transmitting volume holographic gratings. 相似文献
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A holographic Stokesmeter (HSM) utilizes the inherent polarization sensitivity of volume gratings to determine all the Stokes parameters of input beams. A unique feature of the HSM is that it can be designed for spectral multiplexing at a high speed. Here, we report the demonstration of such a spectrally scanning HSM for two different wavelengths. Integration of such an HSM with a polarimetric imaging system will produce a device of potentially significant practical usage: a multi-spectral Stokes parameter camera (MSPC). 相似文献
11.
Burunkova J. A. Denisyuk I. Yu. Zhuk D. I. Sheklanova E. B. 《Optics and Spectroscopy》2017,122(2):341-343
Highly selective volume-diffraction gratings are recorded on a holographic acrylate nanocomposite. The holographic characteristics of the gratings are studied. It is shown that the diffraction efficiency of gratings can reach 50% and a 3D hologram is formed. The refractive index modulation is 0.048–0.065.
相似文献12.
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The formation of holographic transmission and reflection gratings is examined taking into consideration photoinduced absorption
in photopolymer materials. The holographic gratings are assumed to be formed by light beams with arbitrary amplitude profiles.
The problem is solved analytically in the zero-and first-harmonic approximation of the monomer concentration and refractive
index with allowance for the interference-pattern contrast, an arbitrary degree of photopolymerization nonlinearity, and the
dependence of the diffusion coefficient on the degree of polymerization. The effect of beam-amplitude profiles and light-induced
absorption on the spatial profiles of holographic gratings is studied using numerical simulation. The effect of light-induced
absorption on the diffraction characteristics of holographic gratings is discussed.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 81–89, October, 2006. 相似文献
14.
A theoretical method is outlined for the calculation of the profiles of holographic diffraction gratings produced in photo-resist. This method is shown to give results in agreement with all experimental observations of such profiles. Consideration is then given to the flexibility of arrangements for the formation of holographic gratings and an experimental system is discussed which fully utilizes this flexibility. The wide range of profiles which may be generated with such a system is demonstrated. Finally a theoretical programme of investigation is suggested which may well make possible the formation of holographic gratings of greatly improved spectral performance. 相似文献
15.
M. Imlau S. Haussühl T. Woike R. Schieder V. Angelov R.A. Rupp K. Schwarz 《Applied physics. B, Lasers and optics》1999,68(5):877-885
Elementary holographic phase gratings can be written in single crystals of Na2[Fe(CN)5NO]·2H2O, sodiumnitroprusside, by excitation of metastable electronic states in the blue–green spectral range. For light polarized
parallel to the crystallographic a and b axes of the orthorhombic crystal the light-induced modulation of the refractive index
reaches Δn≈2×10-3 at λ=514.5 nm. Although the largest population of the metastable states is reached for light polarized parallel to the crystallographic
c axis, a photorefractive response is not observed. In contrast to electro-optic photorefractive materials the photorefractive
effect depends mono-exponentially on the exposure and on the modulation of the incident light interference pattern. Beam-coupling
experiments demonstrate that written gratings are in phase with the interference pattern in correspondence with the fact that
the excitation of the metastable electronic states is local. The width of the rocking curve shows that the holographic gratings
are written completely over the volume of the crystal. Variations of the wavelengths within the excitation range as well as
of the crystal thickness do not influence the maximum photorefractive response. Investigations on the grating vector of the
written gratings show unambiguously that charge migration is not responsible for the photorefractive effect.
Received: 18 November 1998 / Revised version: 26 January 1999 / Published online: 12 April 1999 相似文献
16.
Experimental study of multiplexed holographic gratings recorded in a photopolymerizable silica glass
A. Murciano L. Carretero S. Blaya R.F. Madrigal A. Fimia 《Applied physics. B, Lasers and optics》2006,83(4):619-622
Recently the capability of photopolymerizable sol–gel materials to angular multiplex holographic gratings has been demonstrated [1, 2]. In this study, holographic transmission gratings were recorded using angular multiplexing in a silica glass doped photopolymer holographic recording material. The time interval between exposures and the angular selectivity were analyzed, in particular their effects on the dynamic range. By using the optimal parameters gratings of similar response were achieved with values of M/#=4.8, as well as good values of diffraction efficiency with high photosensitivity. PACS 42.40.Pa; 42.70.Ln 相似文献
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It is established that DNA films sensitized by organic dyes (for example, acridine orange), subjected to pulsed excitation in the dye absorption band, allow for several types of time-dependent holographic recording. Dynamic holographic gratings on the dye triplet states and thermal and relief-phase holographic gratings of nondestructive type have been recorded. The efficiency and lifetime of these gratings depend strongly on the concentration of dye, the type of its bonding with the biopolymer, and the recording-pulse energy. High-efficiency relief holographic gratings formed due to the structural transformations occurring in the biopolymer matrix when the energy of recording laser pulses dissipates into heat spontaneously and completely (or almost completely) disappear with time at room temperature. Some data on the distribution of acridine orange molecules over binding sites in the DNA matrix are obtained. 相似文献
19.
Wai-Hon Lee 《Optics Communications》1980,34(1):29-31
Three approaches for recording holographic lenses for infrared wavelengths are discussed. For long wavelengths such as the 10.6 μm line from CO2 lasers holographic lenses are best made as computer-generated holograms. For the near infrared holographic lenses can be made using visible wavelengths with a computer-generated hologram to provide aberration correction. Finally a two step procedure is described which can be used to make holographic lenses for most infrared wavelengths. 相似文献
20.
The influence of changes in the average refractive index and thickness of a working medium layer on the holographic record of sloped transmission gratings in photopolymerizable compositions (PPCs) was studied. The parameters of holographic gratings change with increasing slope of grating lines. It is shown that shrinkage of the PPC layer is the main factor influencing the direction and rate of the energy exchange between recording beams and medium during the holographic recording in PPCs. 相似文献