共查询到20条相似文献,搜索用时 15 毫秒
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Yu.A. Cherkasov E.L. Alexandrova M.V. Smirnov A.I. Rumjantzev 《Optics & Laser Technology》1996,28(4):291-295
For spectral holography, the opportunity of using real-time information recording in situ using photothermoplastic (PTP) materials is considered. Applying the physical model of free charge carrier photogeneration for photothermoplastics (PTPs), based on charge transfer complexes, the photosensitivity is investigated considering its dependence on exposure time (exciting laser pulses duration). For sequential PTP processes, it is shown that the experimental values of the photosensitivity over a spectral range of 300–1000 nm is maintained down to picosecond exposures. This is in good agreement with theoretical calculations. It is concluded that, for the achieved values of photosensitivity and taking into account other characteristics of PTPs—such as real-time recording in situ, high values of space resolution (to 1000 line pairs mm−1), diffraction efficiency (to 20%) and cyclability (to 1000 cycles)—PTPs are useful materials for laboratory investigations in the field of spectral holography. 相似文献
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The persistent spectral hole-burning (PSHB) phenomenon observed in molecular doped polymers cooled down to liquid helium temperatures allows the engraving of spectral structures in the inhomogeneous absorption profile of the material. Therefore, a PSHB molecular-doped solid can be programmed in the spectral domain and then converted in an optical processor capable to achieve user-defined optical functions. We demonstrate the high storage capacity of naphthalocyanine-doped polymer materials by engraving and retrieving the phase information stored in femtosecond-chirped pulses, even with nanosecond time delay, which correspond to information registered with sub-GHz spectral resolution. Perspectives for the coherent control of light fields or photochemical processes are also evoked. 相似文献
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On the basis of principles of time holography we suggest a method for recording changes of a spectrum in ultrashort light
pulses with a time resolution of up to 10−14 sec. As a clear way to describe the spectrum kinetics, a function of the spectral shift is introduced. We consider, as an
example, the possibilities of investigating the spectral-temporal structure of pico- and femtosecond pulses and their transformations
on interaction with a dispersion medium.
B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 68, F. Skorina Ave., Minsk, 220072, Belarus.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 1, pp. 25–29, January–February, 1999. 相似文献
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A new scheme for two-dimensional parallel data transmission with a femtosecond laser pulse through a single-mode fiber, which is based upon one-dimensional space-time conversion technique in conjunction with code division multiple access (CDMA), is implemented and numerically demonstrated. Since many one-dimensional spatial data, which are encoded with their own M-sequence code, must be embedded in a single pulse, the bit-error rate performance degrades compared with conventional CDMA driven by many unsynchronized pulses. Still, two-dimensional digital images in a 16 bits × 16 bits plane (256-bits parallel data) are successfully transmitted by a single femtosecond laser pulse at an equivalent transmission rate of 1.6 Tbit/s and recovered by spectral holography. 相似文献
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全息术是一种用相干光干涉得到物体全部信息的2步成像技术。全息术的发展大约可分同轴全息术、离轴全息术、白光再现全息术、白光全息术等4个阶段。全息术具有三维、不可撕毁、再现像的缩放、信息容量大等特点。全息术是一门正在蓬勃发展的光学分支,近年来已渗透到社会生活的各个领域并被广泛地应用于近代科学研究和工业生产中,特别是在现代测试、生物工程、医学、艺术、商业、保安及现代存储技术等方面已显示出特殊的优势。随着全息技术的快速发展,全息技术的产品正越来越多地走向市场、应用于现代生活中。 相似文献
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Holography of wave packets 总被引:3,自引:0,他引:3
We describe the principles of holographic storage and reconstruction of ultrashort light pulses using spectrally nonselective media. This can be achieved by the application of a 3-D recording medium and by the holography of waves produced by spatial spectral decomposition of light pulses. We also describe various transformations of optical temporal signals based on holographic spectral filtering and nonlinear interaction of spectral decomposition waves. 相似文献
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相移同轴无透镜傅里叶数字全息的分析与实验 总被引:12,自引:4,他引:8
应用菲涅耳衍射和全息理论,详细分析了无透镜傅里叶变换数字全息图的记录、再现方法和再现像的特点,分析了相移数字全息图的记录和再现方法,并进行了相应的实验验证。结果表明:直接对无透镜傅里叶数字全息图进行傅里叶逆变换可同时得到与物体完全相同的再现像及其共轭像;同轴无透镜傅里叶数字全息术能最大程度满足CCD对采样条件的要求,从而可以增大记录物体的尺寸,减小记录距离,明显提高再现像的清晰度和分辨率;相移数字全息术能有效地消除数字再现光场中的零级光场和共轭像,显著提高再现像的信噪比。条件许可时,相移同轴无透镜傅里叶数字全息术是目前解决数字全息术中再现像的分离与满足采样条件之间矛盾的最佳方法。 相似文献
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彩虹全息术的综合分析 总被引:2,自引:0,他引:2
本文从物理光学的角度出发,系统地讨论了彩虹全息的像质。对有狭缝和无狭缝彩虹全息术作了分析比较,解释了无狭缝彩虹全息术中合成狭缝的机制,得到清晰的物理图象,最后指出较有应用前景的记录系统。 相似文献
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双随机相位加密全息标识防伪技术研究 总被引:22,自引:0,他引:22
在输入面和频谱面上分别放置随机相位加密模板对图像数据进行加密是一种高密级的有效数据加密技术。在研究双随机相位数据加密技术的基础上,结合数字全息技术和印刷技术的特点,提出了一种新的双随机相位加密同轴相位全息标识(简称同轴相位全息标识)印刷防伪方法。理论分析证明了同轴相位全息标识方法能有效地恢复原始图像数据,仿真实验证明了该方法具有强抗随机干扰能力和抗位压缩性能。通过打印和扫描实验验证了同轴相位全息标识可以通过普通的数字印刷技术印制在证件等印刷品中作为防伪标识,印刷品中的同轴相位全息标识可以通过扫描输入计算机,变换生成数字图像,通过解密模板可从中恢复出原始图像数据。 相似文献
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LED光源数字全息技术研究 总被引:1,自引:0,他引:1
研究以发光二极管(LED)作为光源的部分相干光数字全息技术.首先研究LED的时间相干性和空间相干性,尽管LED的时间相干性较差,但空间相干性可以通过减小光源发光面积来提高.利用LED的时间相干性较差、相干长度短的特点,抑制相干噪声,改善数字全息重建质量.在同一全息记录系统,通过实验,比较了用激光和LED光源的数字全息重建图像质量.结果表明:基于LED光源的数字全息,完全消除了使用激光光源的散斑噪声和由光学元件引入的寄生干涉噪声,物光场的重现质量,包括振幅和相位都得到了很大提高.但由于LED光源的较低的空间相干性,一般只适用于同轴相移数字全息,待测物体的厚度在十几微米以内,应用受到一定限制. 相似文献
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All-optical programmable shaping of narrow-band nanosecond pulses with picosecond accuracy by use of adapted chirps and quadratic nonlinearities 总被引:1,自引:0,他引:1
We experimentally demonstrate pure optical pulse picosecond shaping of narrow-bandwidth nanosecond pulses. The method used is based on the manipulation in the spectral domain of strongly chirped femtosecond pulses and on the use of either frequency addition or frequency difference. 相似文献
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针对雾化场光学全息测量存在干板湿化学处理繁琐、再现像采集耗时的问题,提出光学全息与数字全息联合测量的方法,建立由同轴光学全息、同轴数字全息以及数字延迟信号发生器组成的测量系统,并以双孔直射式喷嘴产生的雾化场为测量对象,利用该测量系统在一次测量中同时获得雾化场的光学全息和数字全息的再现图像,两者具有很好的一致性。光学和数字再现图像相对应的视场范围分别为27.87 mm4.77 mm和27.59 mm6.67 mm,数字方式获得视场范围内单一层面再现像的时间仅为8 s,而光学方式将近1 h。结果表明,光学全息与数字全息联合测量时,通过数字全息的雾化再现图像能够对实验总体效果进行实时评估,提高了雾化场全息测量的实验效率。 相似文献
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I. V. Fedotov A. B. Fedotov A. M. Zheltikov 《Journal of Experimental and Theoretical Physics》2007,105(5):886-892
Photonic-crystal fibers are shown to allow efficient spectral transformation of nanosecond laser pulses through parametric four-wave mixing and stimulated Raman scattering. Regimes providing highly efficient transformation of nanosecond laser pulses into white-light broadband radiation (supercontinuum) are identified. A strong parametric coupling between Stokes and anti-Stokes Raman sidebands around the wavelength of zero group-velocity dispersion is shown to increase the bandwidth and to improve the spectral quality of supercontinuum radiation. 相似文献
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A.A. Ionin I.O. Kinyaevskiy Yu.M. Klimachev A.A. Kotkov A.Yu. Kozlov 《Optics Communications》2012,285(10-11):2707-2714
To increase a peak power of carbon monoxide laser emitting nanosecond pulses a Master Oscillator-Power Amplifier (MOPA) laser system was developed. The MOPA CO-laser system employed one and the same gain medium of wide-aperture pulsed electron-beam-sustained-discharge CO-laser facility. Amplification parameters include gain and saturation intensity of amplifying media. The MOPA CO-laser system emitted a train of nanosecond pulses with peak power up to ~ 0.1 MW on a single spectral line and up to ~ 0.4 MW with multiline spectrum. 相似文献