Holographic forced fluid dynamics in non-relativistic limit

We study the thermodynamics and non-relativistic hydrodynamics of the holographic fluid on a finite cutoff surface in the Gauss–Bonnet gravity. It is shown that the isentropic flow of the fluid is equivalent to a radial component of gravitational field equations. We use the non-relativistic fluid expansion method to study the Einstein–Maxwell-dilaton system with a negative cosmological constant, and obtain the holographic incompressible forced Navier–Stokes equations of the dual fluid at AdS boundary and at a finite cutoff surface, respectively. The concrete forms of external forces are given.     

Demonstration of a spectrally scanned holographic Stokesmeter

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).     

Demonstration of a thick holographic Stokesmeter

A holographic Stokesmeter has the potential to be useful in high-speed polarization imaging applications. Highly polarization-sensitive gratings are an important component for this device. Using two sets of multiplexed gratings, we measured the Stokes parameters for three different polarization states of an input beam. These measured values compared well to values measured using the quarter-wave plate/linear polarizer method. This establishes the feasibility of such a Stokesmeter in its original configuration. We demonstrate further the basic mechanism behind a compact architecture for this device, requiring only a single substrate and a single imaging system, and describe a spectrally scanned polarimetric imaging system.     

Holographic dark energy in a cyclic universe

In this paper we study the cosmological evolution of the holographic dark energy in a cyclic universe, generalizing the model of holographic dark energy proposed by Li. The holographic dark energy with c<1 can realize a quintom behavior; namely, it evolves from a quintessence-like component to a phantom-like one. The holographic phantom energy density grows rapidly and dominates the late-time expanding phase, helping to realize a cyclic universe scenario in which the high energy regime is modified by the effects of quantum gravity, causing a turn-around (and a bounce) of the universe. The dynamical evolution of holographic dark energy in the regimes of low energy and high energy is governed by two differential equations, respectively. It is of importance to link the two regimes for this scenario. We propose a link condition giving rise to a complete picture of holographic evolution of a cyclic universe.     

Tunable dual-wavelength operation of an external cavity semiconductor laser

Tunable dual-wavelength operation of a laser diode has been achieved using a dual-period holographic element. The holographic element was positioned in Littrow configuration in an external cavity. The design of this holographic element was based on the superposition of a constant-period grating and a variable-period grating on the same location in a photoresist. We observed simultaneous emission at two wavelengths from a visible semiconductor laser operated with this holographic element. The spectral separation of the dual-wavelength output was varied from 0.76 to 6.27 nm by a simple translation of the holographic element.     

Bifocal-polarization holographic lens

We present a holographic lens with novel features recorded in an azopolymer film. Two holographic modulations, bulk birefringence and surface relief, are induced in the medium at the same time. The resultant holographic element has two focal planes, and the polarization of light in the focal points depends on the polarization of the incident light. Applications of this device for writing-reading information in two planes simultaneously or separately are described.     

Holographic visualization of laser-induced plume in pulsed laser welding

High-speed holographic interferometry was applied to the experimental study of a laser-induced plasma plume in pulsed laser welding. We adopted two kinds of holographic interferometers for visualizing and imaging the refractive index distribution of the plume and vaporized metal; a real-time holographic interferometer with a high-speed camera and a double-pulsed holographic interferometer with a dual-reference-beam module. The high-speed photographs of the weld plume were compared with the visualized images by holographic interferometer. The experimental results show the process of generation and propagation of the laser-induced plume and give the feasibility of quantitative measurement of the density distribution of the laser-induced plume and vaporized metal in laser welding.     

空间光调制器曲面拼接实现全息三维显示视角拓展

本文对多空间光调制器不同拼接方式拓展全息三维再现像视角的方法进行了分析,基于多片空间光调制器拼接拓展视角的思想,利用平面反射镜、分光镜和两片透射式空间光调制器设计了曲面拼接系统,进行了全息三维再现像的视角拓展实验研究。用该系统对四棱锥物体的层析菲涅尔衍射全息图进行再现,结果表明,总视角由基于单片空间光调制器的1.7°增大到3.2°,即拓展到约1.9倍,分光镜能够消除两片空间光调制器间的间隙,实现无缝拼接。该方法同样适用于更多空间光调制器的曲面拼接中,可以有效地拓展全息再现像的视场角大小。     

Holographic Gas as Dark Energy

We investigate the statistical nature of holographic gas, which may represent the quasi-particle excitations of a strongly correlated gravitational system. We find that the holographic entropy can be obtained by modifying degeneracy. We calculate thermodynamical quantities and investigate stability of the holographic gas. When applying to cosmology, we find that the holographic gas behaves as holographic dark energy, and the parameter c in holographic dark energy can be calculated from our model. Our model of holographic gas generally predicts c 〈 1, implying that the fate of our universe is phantom-like.     

Experimental verification of the electromagnetic spectral interference law using a modified version of the Young's interferometer

We present a method to verify the electromagnetic spectral interference law experimentally, which connects the combined two-beam usual Stokes parameters with the corresponding single beam usual Stokes parameters. Using polarizers and phase retarders in a modified version of the Young's interferometer, the usual Stokes parameters and the generalized Stokes parameters are determined for a laser beam. The experimentally determined single point (usual) Stokes parameters at an axial point in the observation plane for the combined beam are compared with their theoretically expected values obtained by putting the experimental data in the electromagnetic spectral interference law. A fairly good agreement is found between the two values. Not only does the proposed method provides a comparison between the two kinds of Stokes parameters but also validates the role of the generalized Stokes parameters as modulation parameters for the usual Stokes parameters.     

Higher derivative corrections in holographic Zamolodchikov–Polchinski theorem

We study higher derivative corrections in holographic dual of Zamolodchikov–Polchinski theorem that states the equivalence between scale invariance and conformal invariance in unitary d-dimensional Poincaré invariant field theories. From the dual holographic perspective, we find that a sufficient condition to show the holographic theorem is the generalized strict null-energy condition of the matter sector in effective (d+1)-dimensional gravitational theory. The same condition has appeared in the holographic dual of the “c-theorem” and our theorem suggests a deep connection between the two, which was manifested in two-dimensional field theoretic proof of the both.     

Three-dimensional imaging with monocular cues using holographic stereography

Two quantitative criteria are derived to evaluate monocular cues in holographic stereograms. We find that the reconstruction has correct monocular cues when the whole scene is located in a so-called "monocular cues area" with compatible monocular and binocular cues. In contrast, incorrect monocular cues appear when the scene is in the other two areas, namely, the "visible multi-imaging area" and the "lacking information area." A pupil-function integral imaging algorithm is developed to simulate monocular observation, and a holographic printing system is set up to fabricate full-parallax holographic stereograms. Both simulations and experiments agree with the criteria.     

Holographic superconductor developed in BTZ black hole background with backreactions

We develop a holographic superconductor in BTZ black hole background with backreactions. We investigate the influence of the backreaction on the condensation of the scalar hair and the dynamics of perturbation in the background spacetime. When the Breitenlohner-Freedman bound is approached, we argue that only one of two possible operators can reflect the real property of the condensation in the holographic superconductor. This argument is supported by the investigation in dynamics.     

Real-time holographic interferometry using sillenite photorefractive crystals. Study and optimization of a transportable set-up for quantified phase measurements on large objects

We present the development of a holographic interferometer that uses a photorefractive crystal of the sillenite family as holographic recording medium. The aim of this work is to achieve a transportable and breadboard instrument, with a flexible design and which is user friendly for the quantified measurements of displacements on large scattering objects. The state of the art of the use of photorefractive crystals in holographic interferometry is presented. Based on the latter, a method that is the best suited to our mentioned objectives is chosen: the real-time interferometric technique associated with the crystal configuration exhibiting diffraction anisotropy. On this basis, we have studied and compared two imaging systems, we have experimentally determined the holographic figures of merit of three sillenite crystals samples, and, finally, we have shown the use of two measurement quantification methods. The result of these investigations is a certified and transportable holographic camera prototype containing all the necessary equipment for its operation, which can be easily adapted to various applications. Among these, we show its use in the detection of defects in composite structures, in the measurement of time-evolving deformations, and in the measurement of vibration modes. Received: 4 December 1998 / Revised version: 6 March 1999 / Published online: 12 April 1999     

Direct laser writing defects in holographic lithography-created photonic lattices

As a well-established laser fabrication approach, holographic lithography, or multibeam interference patterning, is known for its capability to create long-range ordered large-volume photonic crystals (PhCs) rapidly. Its broad use is, however, hampered by difficulty in inducing artificially designed defects for device functions. We use pinpoint femtosecond laser ablation to remove and two-photon photopolymerization to add desired defective features to obtain photonic acceptors and photonic donors, respectively, in an otherwise complete PhC matrix produced by holographic lithography. The combined use of the two direct laser writing technologies would immediately make holographic lithography a promising industrial tool for PhC manufacture.     

Compact and portable holographic camera using photorefractive crystals. Application in various metrological problems

We present a compact holographic interferometer that uses a photorefractive crystal of the sillenite family as a holographic recording medium. Its development is based on a previous prototype that showed lack of flexibility and portability. We briefly discuss the main improvements leading to a compact device. Applications of this instrument in various metrological problems are shown, among which are two that were not already considered using holography, namely measurement of a thermal expansion coefficient and detection of fingerprints. Received: 20 December 2000 / Revised version: 8 February 2001 / Published online: 20 April 2001     

Entropy Bound Derived from the New Thermodynamics on Holographic Screen

We introduce a new interpretation of chemical potential and show that holographic entropy is entropy bound, which is supported by two ideal cases discussed in detail. One is sparse but incompressible liquid like a star of uniform density and the other is a screen at infinity in spherically symmetric spacetime. Our work is based on the new scenario of entropy force and holographic thermodynamics, and the Brown-York quasi-local energy.     

Sonic velocity in holographic fluids and its applications

Gravity/fluid correspondence acts as an important tool in investigating the strongly correlated fluids.We carefully investigate the holographic fluids at the finite cutoff surface by considering different boundary conditions in the scenario of gravity/fluid correspondence. We find that the sonic velocity of the boundary fluids at the finite cutoff surface is critical in clarifying the superficial similarity between the bulk viscosity and perturbation of the pressure for the holographic fluid, where we set a special boundary condition at the finite cutoff surface to explicitly express this superficial similarity. Moreover, we further take the sonic velocity into account to investigate a case with a more general boundary condition. In this more genaral case, although two parameters in the first order stress tensor of holographic fluid cannot be fixed, one can still extract the information about the transport coefficients by considering the sonic velocity seriously.