摘要:

The phase shift experienced by a light wave when it passes through a focus (the Gouy phase shift) can be regarded as a geometrical effect arising, via the uncertainty principle, from a modification of the volume of space available for the propagation of the photon. This effect is closely related to the shift in the phase of the wave function of a particle travelling along a tube; however, it does not require the presence of physical boundaries.

ISSN:0950-0340    

DOI:10.1080/09500349608232735

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The atomic squeezed states are known to exhibit oscillatory population distributions. The origin of these oscillations is traced back to different pathways that contribute to the amplitude of oscillations. The zeros in the population distribution are due to complete destructive interference between two pathways.

ISSN:0950-0340    

DOI:10.1080/09500349608232736

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

We report on various novel uses of resonance domain diffractive optics. Here we primarily concentrate on the design of optical elements that act as 90° beam deflectors for a high-power laser. Two of the elements were binary surface relief gratings, one acting as a highly reflecting leaky waveguide and the second was a transmission grating operating at Bragg incidence. Both of these devices could be optimized for efficiencies approaching 100%. A third device consisting of dielectric micro prisms was also considered. The results have direct relevance to moderate to high power laser systems, where laser induced damage is a potential limiting factor for any multi-layer thin film or bulk optical element.

ISSN:0950-0340    

DOI:10.1080/09500349608232737

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

We discuss the symmetric multiport and show in a constructive way how it can be decomposed into a set of beam splitters. Based on the decomposition we estimate the number of beam splitters needed. It is shown that for more than three input ports the number of beam splitters needed is less than the number indicated by the standard decomposition scheme.

ISSN:0950-0340    

DOI:10.1080/09500349608232738

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

We have observed various types of photon echoes in a rare-earth doped crystal using a broad-band c.w. dye laser. Even at the very low spectral power density of the laser, the quantum efficiency of photon echo generation is as large as those using high-power or narrow-band lasers. We have observed Carr-Purcell type photon echo series for the first time in a rare-earth doped crystal. We have measured relaxation of two-pulse photon echo, three-pulse stimulated photon echo, and many-pulse Carr-Purcell photon echo, and found some new features.

ISSN:0950-0340    

DOI:10.1080/09500349608232739

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

We study the features of noiseless amplification in a general class of optical systems, characterized by an intracavity nonlinearity which induces a two-photon process, in the limit where the damping constant of the mode which undergoes the two-photon process greatly exceeds all other relaxation rates of the system. By applying a previously formulated analytical approach, we write the universal-form expressions for the linear amplification factor and the noise figure. Noiseless amplification is attainable under resonance conditions.

ISSN:0950-0340    

DOI:10.1080/09500349608232740

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

We consider a cavity containing both a χ(2)-nonlinear material and a laser two-level medium for the cases of self-frequency-doubling and self-down-converting configurations. For both situations, the squeezing properties of the two fields are analysed in detail, while special attention is devoted to the problem of ‘noiseless amplification’ of a small monochromatic signal injected in the lower frequency mode.

ISSN:0950-0340    

DOI:10.1080/09500349608232741

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A compact pupil plane wavefront sensor is described, which is able to image on a single detector four images of the pupil, containing information on the gradient of the incoming wavefront. The wavefront sensor consists of a lens relay and an oscillating pyramidal-shaped prism. The gain of the device is driven by the amplitude of the oscillations, while the sampling is determined by the focal length of the lens relay. This wavefront sensor can be conveniently used for astronomical adaptive optics purposes because of its flexibility to match the brightness of the reference source used (varying the sampling) and the seeing conditions (varying the gain).

ISSN:0950-0340    

DOI:10.1080/09500349608232742

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A generalization of the main linear and nonlinear correlation methods, the dual nonlinear correlation (DNC), is introduced. Various filters (CMF, POF, IF, FPF, PPC, OF) appear to be special cases of the DNC. The convolution formula describing the peak shape and the intermodulation effects for the noise-free multi-object scenes is discussed. Optimization of the DNC according to the peak-to-correlation energy criterion is performed. Superior performance of the PPC is presented. The influence of noise on the intermodulation effects is studied. Hybrid, optoelectronic realization of the DNC based on joint transform correlator architecture with nonlinear preprocessing which allows the introduction of various correlation methods without any fiters is proposed.

ISSN:0950-0340    

DOI:10.1080/09500349608232743

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

As a result of the original theoretical analysis in different approximations we show that the steady-state photoinduced photorefractive lens formed under an external transverse d.c. electric field by the light beam with cylindrical symmetry is essentially astigmatic. This behaviour is demonstrated in self-focusing-defocusing experiments with cubic Bi12TiO20photorefractive crystals at λ=633 nm. The result implies in particular that the steady-state (2+1)-dimensional spatial solitons generated in photorefractive crystals under similar conditions are to be characterized by an elliptic cross-section.

ISSN:0950-0340    

DOI:10.1080/09500349608232744

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor