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Showing papers in "Journal of Modern Optics in 1994"


Journal ArticleDOI
TL;DR: In this article, the authors propose a definition of fidelity for mixed quantum states in terms of Uhlmann's transition probability formula F(ϱ1, ϱ2) = {trace [(√ϱ 1ϱ2 × √ ϱ 1)1/2]}2 and give new elementary proofs of its essential properties.
Abstract: We propose a definition of fidelity for mixed quantum states in terms of Uhlmann's ‘transition probability’ formula F(ϱ1, ϱ2) = {trace [(√ϱ1ϱ2 × √ϱ1)1/2]}2 and give new elementary proofs of its essential properties.

1,599 citations


Journal ArticleDOI
TL;DR: In this article, the authors describe in detail how to make numerical calculations of the dispersion relations (the band structure) of these complex objects, and how to calculate transmission through, and reflection from them.
Abstract: Building complex materials with structures on a scale comparable to the wavelength of light offers possibilities for radically changing the way light moves around such materials, in the same way that we engineer atomic structure to vary electronic properties of semiconductors. In this paper we describe in detail how to make numerical calculations of the dispersion relations (the band structure) of these complex objects, and how to calculate transmission through, and reflection from them. Finally these methodologies are applied to a colloidal dispersion of metallic particles at 12% volume filling fraction to reproduce the well known characteristics of strong optical absorption.

457 citations


Journal ArticleDOI
TL;DR: In this article, the diffusion equation is solved in the low-order harmonic approximation, in order to describe the grating formation process in dry photopolymer materials, and the ratio between diffusion and polymerization rates is described.
Abstract: The diffusion equation is solved in the low-order harmonic approximation, in order to describe the grating formation process in dry photopolymer materials. We describe how the ratio between diffusion and polymerization rates controls the process of grating formation. Nonlinearity and reciprocity failure are predicted. Experimental results are also shown which are in qualitative agreement with the theory.

340 citations


Journal ArticleDOI
TL;DR: In this paper, the Optics and Nonlinear Optics of Liquid Crystals of liquid crystals are discussed. But they do not consider the nonlinear properties of the liquid crystal lattice.
Abstract: (1994). Optics and Nonlinear Optics of Liquid Crystals. Journal of Modern Optics: Vol. 41, No. 7, pp. 1517-1518.

313 citations


Journal ArticleDOI
TL;DR: An account of the quantum noiseless coding theorem, including a new proof based on a simplified block coding scheme, and an illustrative example of quantum coding.
Abstract: We give an account of the quantum noiseless coding theorem, including a new proof based on a simplified block coding scheme. We also discuss an illustrative example of quantum coding.

311 citations


Journal ArticleDOI
TL;DR: A simple general prescription for a measurement that is typically not optimal but appears to be quite good is considered, which seems to be particularly good when the states to be distinguished are equally likely and almost orthogonal.
Abstract: We address the problem of extracting information from a single quantum system whose state is known to be in one of several possible states. In the generic case, it is notoriously difficult to find the optimal measurement, that is the measurement that provides the most possible information about the system's state. We consider a simple general prescription for a measurement that is typically not optimal but appears to be quite good. It seems to be particularly good when the states to be distinguished are equally likely and almost orthogonal.

306 citations


Journal ArticleDOI
TL;DR: A simple approach to generating the random measurement bases used in quantum cryptography systems which exploits random partition at a beam splitter, reducing system complexity and losses.
Abstract: We review the status of interferometry-based quantum cryptography and compare photon-pair and faint-pulse schemes. The key technical limitations in both cases are the propagation losses and detector performance. We also discuss a simple approach to generating the random measurement bases used in quantum cryptography systems which exploits random partition at a beam splitter. This removes the need for active components in the receiver, reducing system complexity and losses.

265 citations


Journal ArticleDOI
TL;DR: In this paper, a comprehensive quantum electrodynamical analysis of the interaction between a continuum with photonic band gaps (PBGs) or frequency cut-off and an excited two-level atom, which can be either bare or dressed by coupling to a near-resonant field mode, is presented.
Abstract: We present a comprehensive quantum electrodynamical analysis of the interaction between a continuum with photonic band gaps (PBGs) or frequency cut-off and an excited two-level atom, which can be either ‘bare’ or ‘dressed’ by coupling to a near-resonant field mode. A diversity of novel features in the atom and field dynamics is shown to arise from the non-Markovian character of radiative decay into such a continuum of modes. Firstly the excited atom is shown to evolve, by spontaneous decay, into a superposition of non-decaying single-photon dressed states, each having an energy in a different PBG, and a decaying component. This superposition is determined by the atomic resonance shift, induced by the spontaneously emitted photon, into or out of a PBG. The main novel feature exhibited by the decaying excited-state component is the occurrence of beats between the shifted atomic resonance frequency and the PBG cut-off frequencies, corresponding to a non-Lorentzian emission spectrum. Secondly the ind...

249 citations


Journal ArticleDOI
TL;DR: In this article, the separation of the total angular momentum J of the electromagnetic field into a spin part S and an orbit part L was investigated, and it was shown that both spin and orbit angular momentum are independent.
Abstract: We investigate the separation of the total angular momentum J of the electromagnetic field into a ‘spin’ part S and an ‘orbital’ part L. We show that both ‘spin’ and ‘orbital’ angular momentum are ...

234 citations


Journal ArticleDOI
TL;DR: In this paper, the Quantum Theory of Motion (QTM) is used to describe the behavior of the quantum system in terms of motion and the quantum theory of motion (QTOM).
Abstract: (1994). The Quantum Theory of Motion. Journal of Modern Optics: Vol. 41, No. 1, pp. 168-169.

227 citations


Journal ArticleDOI
TL;DR: In this article, the authors computed the photonic band structure for tree-pile structures having the periodicity of the simple tetragonal lattice and bandgaps have been found.
Abstract: Photonic band structure has been computed for ‘woodpile’ structures having the periodicity of the simple tetragonal lattice. Bandgaps have been found. Further research directions are explored.

Journal ArticleDOI
TL;DR: The direct mapping formula can be generated by measuring the phases of several different parallel planes rather than geometric parameters of the optical system to speed up the calculation and reduce systematic errors.
Abstract: A direct phase-to-height mapping algorithm for phase-measuring profilometry is presented and verified by experiments. The direct mapping formula can be generated by measuring the phases of several different parallel planes rather than geometric parameters of the optical system. Therefore, it can speed up the calculation and reduce systematic errors.

Journal ArticleDOI
TL;DR: In this article, a simple one-dimensional Kronig-penney model of a three-dimensional bandgap structure is presented, where the effective index of refraction can become less than unity and in fact can approach zero at the band edge itself.
Abstract: Near the gap in a photonic bandgap material the effective index of refraction can become less than unity and in fact can approach zero at the band edge itself—leading to ultra-refractive optical effects. We illustrate this effect quantitatively in a simple one-dimensional Kronig-Penney model of a three-dimensional bandgap structure. As a complement to index-enhancing schemes involving lasing without inversion, ultra-refractive optics with photonic band materials has many applications, including laser accelerators and lenses of ultra-short focal lengths.

Journal ArticleDOI
TL;DR: In this article, the application of the fractional Fourier transform to optical propagation problems is discussed, and the conceptual and practical advantages of this new formulation are noted, as well as the theoretical advantages of the new formulation.
Abstract: The application of the fractional Fourier transform to optical propagation problems is discussed. As illustrative examples, diffraction in a free medium as well as propagation through optical fibres are analysed with the fractional Fourier transform formalism. The conceptual and practical advantages of this new formulation are noted.

Journal ArticleDOI
TL;DR: A new design for a one-out-of-two oblivious transfer based on the transmission of polarized light is presented, improving the work of Wiesner and Bennett, Brassard, Breidbart and Wieser, and shows that the scheme is robust to general attacks.
Abstract: In a one-out-of-two oblivious transfer, a party Alice has two messages m 0, m 1 that she sends to another party Bob in such a way that he can decide to obtain either of them at his choosing, but not both. Alice never finds out which message Bob received. First introduced by Wiesner as ‘conjugate coding’, this cryptographic tool was later introduced to the world of public-key cryptography, first by Rabin (in a slightly different form) and then by Even, Goldreich and Lempel who named it after Rabin's primitive, called oblivious transfer. The one-out-of-two oblivious transfer was later shown to be extremely powerful in designing general cryptographic tools. The current paper presents a new design for a one-out-of-two oblivious transfer based on the transmission of polarized light, improving the work of Wiesner and Bennett, Brassard, Breidbart and Wiesner, and shows that the scheme is robust to general attacks.

Journal ArticleDOI
TL;DR: In this article, the alteration of spontaneous emission characteristics in terms of the spontaneous lifetime and spectral emission characteristics are discussed for dipoles in the presence of nearby planar reflecting interfaces and cavities, specifically for the case of semiconductors.
Abstract: The alteration of spontaneous emission characteristics in terms of the spontaneous lifetime and spectral emission characteristics are discussed for dipoles in the presence of nearby planar reflecting interfaces and cavities, specifically for the case of semiconductors. For dipoles closely spaced to absorbing metal mirrors, significant lifetime change is possible. Analysis and experimental data are presented for light emitting diodes. For dielectric Fabry-Perot microcavities, the expected lifetime change is small, but significant modification in the radiation pattern of the emitted light occurs. It is shown that the spectral characteristics of emission have a sensitive dependence on the dipole location in the cavity. Comparison is made between a classical against a quantum treatment of the spontaneous emission modification due to the cavity.

Journal ArticleDOI
TL;DR: In this article, the dispersion curves of electromagnetic waves propagating in a structure consisting of an infinite array of parallel, infinitely long, dielectric rods of arbitrary cross-section, embedded in a medium characterized by a 2D Bravais lattice, were calculated.
Abstract: By the use of the plane wave method we have calculated the dispersion curves (photonic band structure) of electromagnetic waves propagating in a structure consisting of an infinite array of parallel, infinitely long, dielectric rods of arbitrary cross-section, characterized by a dielectric constant ea, embedded in a medium characterized by a dielectric constant eb, when the intersections of the axes of the rods with a perpendicular plane form a two-dimensional Bravais lattice. In contrast with earlier calculations of the photonic band structures of two-dimensional, periodic, dielectric structures, in the present work the electromagnetic waves are assumed to propagate out of the plane perpendicular to the rods. In numerical calculations we study a triangular lattice of air cylinders in a dielectric medium, which has recently been shown to possess a band gap common to waves of both E and H polarization for propagation in the plane perpendicular to the rods. The shifts of the edges of this absolute ...

Journal ArticleDOI
TL;DR: In this paper, the authors present theoretical analysis and experimental results for pulsed 2 μm coherent laser radar (Lidar) systems for wake vortex detection and tracking at Denver Stapleton International Airport.
Abstract: Pulsed solid-state coherent laser radar (lidar) systems can measure radial wind velocity to precisions well below 1 m s−1 at spatial scales on the order of 30–50 m and to ranges of several kilometres. This capability is appropriate for a variety of measurement objectives in the airport terminal area. Wake vortex detection and tracking is one of the primary objectives currently being evaluated by regulatory agencies in the United States and elsewhere. Up to now, non-invasive measurement of wake vortex properties has been limited to short-range continuous-wave lidar systems. This paper discusses this application and presents theoretical analysis and experimental results for pulsed 2 μm coherent lidar. Detection, tracking, and measurement results are presented for sample DC10, 757, and 727 aircraft landings from a laser radar wake vortex database compiled in 1993 at Denver Stapleton International Airport.

Journal ArticleDOI
TL;DR: In this paper, a simple model in which a twisted Gaussian Schell-model beam is produced by an incoherent superposition of ordinary Gaussian beams is presented, and the meaning and some direct consequences of the model are given.
Abstract: We present a simple model in which a twisted Gaussian Schell-model beam is produced by an incoherent superposition of ordinary Gaussian beams. The meaning and some direct consequences of the model are given.

Journal ArticleDOI
TL;DR: Oracles are constructed relative to which there is a decision problem that can be solved with certainty in worst-case polynomial time on the quantum computer, yet it cannot be solved classically in probabilistic expected polynometric time if errors are not tolerated.
Abstract: Building on the work of Deutsch and Jozsa, we construct oracles relative to which (1) there is a decision problem that can be solved with certainty in worst-case polynomial time on the quantum computer, yet it cannot be solved classically in probabilistic expected polynomial time if errors are not tolerated, nor even in nondeterministic polynomial time, and (2) there is a decision problem that can be solved in exponential time on the quantum computer, which requires double exponential time on all but finitely many instances on any classical deterministic computer.

Journal ArticleDOI
TL;DR: In this article, the authors demonstrate theoretically and experimentally a fourfold increase in axial point resolution in far-field light microscopy by coherently illuminating the specimen with two opposing objective lenses (4Pi confocal microscopy) and applying two-photon excitation.
Abstract: We demonstrate theoretically and experimentally a fourfold increase in axial point resolution in far-field light microscopy. The resolution enhancement is achieved by coherently illuminating the specimen with two opposing objective lenses (4Pi confocal microscopy) and applying two-photon excitation. The point spread function and the axial resolution of this set-up are calculated in optical units. The axial resolution is measured and compared with predictions, both for the confocal and for the 4Pi confocal set-up, in single as well as in two-photon excitation mode.

Journal ArticleDOI
TL;DR: For complete spherical concentration of light, the maximum theoretically possible total energy density for a given power input can be, in principle, achieved by appropriate choice of polarization and angular amplitude variation.
Abstract: For complete spherical concentration of light the maximum theoretically possible total energy density for a given power input can be, in principle, achieved by appropriate choice of polarization and angular amplitude variation. Illumination of a focusing system with a plane-polarized wave creates at the focus equal electric and magnetic energy densities. By appropriate choice of radial variation this energy density can be maximized. For hemispherical concentration the electric energy density can be seven sixteenths of the maximum possible for a given power input, and the total energy density can be seven eighths of the maximum possible. Focusing by optical systems satisfying the sine condition amongst others is also considered. For a system satisfying the sine condition, the total energy density can be 64/75 of the maximum possible.

Journal ArticleDOI
TL;DR: This work provides an upper and a lower limit on the amount of information that may have leaked to the eavesdropper at the end of the key distribution procedure, which is higher than has been estimated so far.
Abstract: We analyse the information obtained by an eavesdropper during the various stages of a quantum cryptographic protocol associated with key distribution. We provide both an upper and a lower limit on the amount of information that may have leaked to the eavesdropper at the end of the key distribution procedure. These limits are restricted to intercept/resend eaves-dropping strategies. The upper one is higher than has been estimated so far, and should be taken into account in order to guarantee the secrecy of the final key, which is subsequently obtained via the so-called privacy amplification.

Journal ArticleDOI
TL;DR: In this article, the canonical form for Mueller matrices in polarization optics is derived, and it is shown that a non-singular real 4 × 4 matrix M qualifies to be the bona fide Mueller matrix of some physical system if and only if M = L′ ΛL, where L and L′ are elements of the proper orthochronous Lorentz group L ↑ +.
Abstract: The normal (canonical) form for Mueller matrices in polarization optics is derived: it is shown that a non-singular real 4 × 4 matrix M qualifies to be the bona fide Mueller matrix of some physical system if and only if it has the canonical form M = L′ ΛL, where L and L′ are elements of the proper orthochronous Lorentz group L ↑ +, and where Λ = diag (λ0, λ1, λ2, λ3) with λ0 ≥ ¦λj¦ > 0. It is further shown that λ1 and λ2 can be taken to be positive so that the signature of λ3 is the same as that of det M. Several experimentally measured Mueller matrices are analysed in the light of the normal form. The case of singular Mueller matrices is briefly discussed as a limiting case.

Journal ArticleDOI
TL;DR: In this paper, a review of theoretical calculations on three-dimensional photonic band structures is presented, and salient features of the electromagnetic dispersion spectrum are discussed and speculation on possible future research directions are offered.
Abstract: This article is a review of theoretical calculations on three-dimensional photonic band structures. The salient features of the electromagnetic dispersion spectrum are discussed and speculation on possible future research directions are offered.

Journal ArticleDOI
TL;DR: In this article, an achromatic phase shifter operating on the geometric phase can be used to evaluate the fringe contrast directly and to locate the position of the zero-order white-light fringe along the scanning axis.
Abstract: Interferometric profilers suffer from phase ambiguities if the measurement range involves a change in the optical path difference greater than a wavelength This limitation has been overcome by using white light and scanning the object in height We show how an achromatic phase shifter operating on the geometric phase can be used to evaluate the fringe contrast directly and to locate the position of the zero-order white-light fringe along the scanning axis


Journal ArticleDOI
TL;DR: The Cooperative Effects in Optics (CEI) as mentioned in this paper is an extension of the cooperative effects in the Optics Journal of Modern Optics: Vol. 41, No. 3, pp. 657-657.
Abstract: (1994). Cooperative Effects in Optics. Journal of Modern Optics: Vol. 41, No. 3, pp. 657-657.

Journal ArticleDOI
TL;DR: In this paper, the properties of 2D photonic lattices, and especially the presence of photonic band-gaps, are reviewed using symmetry arguments, general conditions on the nature of the eigenmodes for all 2D periodic dielectric lattices are derived.
Abstract: The properties of 2D photonic lattices, and especially the presence of photonic band-gaps, are reviewed. Using symmetry arguments, general conditions on the nature of the eigenmodes for all 2D periodic dielectric lattices are derived. A method of computing photonic band-structures is briefly discussed. The in-plane band-structures of the square and triangular lattices of cylinders are systematically investigated. The out-of-plane band-structure for a prototypical system is described. Effects of periodicity-breaking are discussed, including localization of light due to lattice defects, and localized surface modes.

Journal ArticleDOI
TL;DR: In this paper, an all-fibre quantum cryptography set-up based on the polarization of single photon pulses is described, and the feasibility of establishing a key over more than 1 km has been experimentally demonstrated.
Abstract: An all-fibre quantum cryptography set-up based on the polarization of single photon pulses is described. The feasibility of establishing a key over more than 1 km has been experimentally demonstrated. The limits due to the topological effects, the birefringence, and the polarization mode dispersion of fibres are discussed. A set-up using only two non-orthogonal polarization states and polarizers instead of analysers is proposed.