Use of a random phase mask for the recording of fourier transform holograms of data masks.
TL;DR: This work reports here on the use of a phase mask which imparts a phase shift of 180 degrees to half the data spots chosen at random and shows that the intensity in the Fourier transform plane is now proportional to the intensity of the Fouriers of one single data spot.
Abstract: In a holographic page-oriented memory the information is stored in an array of holograms. It is advantageous to record the Fourier transform of the original data mask because the minimum space bandwidth is then required and the information about any one data bit is spread over the hologram plane. In the Fourier transform plane most of the light is concentrated in an array of bright “spikes” because the data mask consists of an array of equidistant data spots. Some means is needed to distribute the light more evenly. We report here on the use of a phase mask which imparts a phase shift of 180° to half the data spots chosen at random. An analysis shows that the intensity in the Fourier transform plane is now proportional to the intensity of the Fourier transform of one single data spot.
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TL;DR: This review summarizes the algorithms behind, and practical applications of, single particle tracking, and highlights some applications of SPT to study various biological and synthetic materials systems.
Abstract: After three decades of developments, single particle tracking (SPT) has become a powerful tool to interrogate dynamics in a range of materials including live cells and novel catalytic supports because of its ability to reveal dynamics in the structure–function relationships underlying the heterogeneous nature of such systems In this review, we summarize the algorithms behind, and practical applications of, SPT We first cover the theoretical background including particle identification, localization, and trajectory reconstruction General instrumentation and recent developments to achieve two- and three-dimensional subdiffraction localization and SPT are discussed We then highlight some applications of SPT to study various biological and synthetic materials systems Finally, we provide our perspective regarding several directions for future advancements in the theory and application of SPT
361 citations
PARC1
TL;DR: The computer-generated holograms have their greatest potential in the area of interferometry and have been shown to be useful in supplementing existing methods of optical testing.
Abstract: Publisher Summary This chapter describes the techniques and applications of computer-generated holograms. “Computer-generated holograms,” “synthetic holograms,” and “computer holograms” are terms used to refer to a class of holograms that are produced as graphical output from a digital computer. Given a mathematical description of a wavefront or an object represented by an array of points, the computer can calculate the amplitude transmittance of the hologram and display the result on a CRT or plot it on paper. Using photoreduced copy of the graphical output from a computer as holograms is only one of the many things that distinguish computer generated holograms from conventional ones. The computer-generated holograms have their greatest potential in the area of interferometry. They have been shown to be useful in supplementing existing methods of optical testing. Laser beam scanning is another promising area for computer-generated holograms. Holographic grating scanners are in many ways better than other mechanical mirror scanners.
266 citations
TL;DR: The methods and techniques of computer generated holograms are surveyed and the meanings of that term have grown with increased use of the invention.
Abstract: Since Gabor's first hologram, the meanings of that term have grown with increased use of the invention. Computers expanded applications further, and this paper surveys the methods and techniques of computer generated holograms.
211 citations
TL;DR: A method of computer generating binary holograms based on the decomposition of a complex value into two phase quantities is described, and noise due to the displacement of the subcells and the phase coding is discussed.
Abstract: A method of computer generating binary holograms based on the decomposition of a complex value into two phase quantities is described. Each Fourier transform cell is divided into subcells, and phase quantities are encoded by the detour phase technique. Noise due to the displacement of the subcells and the phase coding is discussed. Methods of suppressing this noise are also included.
199 citations
TL;DR: In this article, the authors describe theoretical and experimental investigations of induced spatial incoherence (ISI), a technique for achieving the smooth and controllable target beam profiles required for direct-drive laser fusion.
Abstract: This paper describes theoretical and experimental investigations of induced spatial incoherence (ISI), a technique for achieving the smooth and controllable target beam profiles required for direct‐drive laser fusion In conventional ISI, a broadband laser beam (coherence time tc=1/Δν≪tpulse) is sliced into an array of mutually incoherent beamlets by echelon structures that impose successive time delay increments Δt>tc A focusing lens then overlaps those beamlets onto the target, which is usually located at the far field Here, we evaluate the ideal target beam profiles for practical ISI focusing configurations, and examine the perturbing effects of transient interference, laser aberration, and plasma filamentation Analytic and numerical calculations show that nonuniformities due to interference among the beamlets are smoothed by both thermal diffusion and temporal averaging Under laser‐plasma conditions of interest to inertial confinement fusion (ICF), average ablation pressure nonuniformities ∼1% sho
168 citations
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TL;DR: In this paper, the authors used the representations of the noise currents given in Section 2.8 to derive some statistical properties of I(t) and its zeros and maxima.
Abstract: In this section we use the representations of the noise currents given in section 2.8 to derive some statistical properties of I(t). The first six sections are concerned with the probability distribution of I(t) and of its zeros and maxima. Sections 3.7 and 3.8 are concerned with the statistical properties of the envelope of I(t). Fluctuations of integrals involving I2(t) are discussed in section 3.9. The probability distribution of a sine wave plus a noise current is given in 3.10 and in 3.11 an alternative method of deriving the results of Part III is mentioned. Prof. Uhlenbeck has pointed out that much of the material in this Part is closely connected with the theory of Markoff processes. Also S. Chandrasekhar has written a review of a class of physical problems which is related, in a general way, to the present subject.22
5,806 citations
TL;DR: A specific semipermanent memory design is described which uses a laser light source, an acoustic xy light deflector and an array of 104 holograms as information storage elements and has a total capacity of 108 bits with an access time of less than 10 μsec.
Abstract: The potential of high-speed optical memories using electro-optic or acousto-optic light deflection for address selection is examined. It is shown that for such memories the total memory capacity decreases as the third power of the addressing rate and that capacities in excess of 108 bits are feasible with a random access rate of 106 addresses/sec. A specific semipermanent memory design is then described which uses a laser light source, an acoustic xy light deflector and an array of 104 holograms as information storage elements. Each storage element contains 104 bits which appear as a pattern on a semiconductor read-out matrix when the storage element is illuminated through the xy deflector. Accordingly, the system has a total capacity of 108 bits with an access time of less than 10 μsec.
43 citations