摘要:

Es wird eine neue Möglichkeit für einen linienabstimmbaren Gitter-Resonator eines Bandleiterlasers vorgestellt. Zur Auskopplung der Laserleistung wird ein speziell tastverhältnismoduliertes Gitter verwendet, das bei der Verwendung eines stabilen Resonatoraufbaus auch bei großen Kanalbreiten noch zu einer guten Diskriminierung transversaler Resonatormoden und somit zum bevorzugten Anschwingen des gewünschten Grundmodes führt.

ISSN:0950-0340    

DOI:10.1080/09500349708230747

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

It is known that squeezing the signal field can enhance the detection efficiency in Wigner function measurements using optical tomography. There exists an equivalence between squeezing the signal field and squeezing the local oscillator state when the detection efficiency is unity. We compare the cases of squeezing the local oscillator field and squeezing the signal field in the light of improving the detection efficiency in homodyne measurements.

ISSN:0950-0340    

DOI:10.1080/09500349708230748

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

We investigate numerically the probability distribution density dynamics of phase in second harmonic generation in the region of instability. It is shown that in this system the quantum macroscopic Schrödinger-cat-like states of both modes can appear. The behaviour of the system moving through the critical point is also illustrated.

ISSN:0950-0340    

DOI:10.1080/09500349708230749

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Scattering calculations via the Schwinger variational principle are exemplified for the canonical model ofE∥plane waves incident on a planarsinusoidal perfect-reflector surface. The complete solution is obtained in terms of a contour integral from which analytic limits are derived that agree with exact results. The contour integral is then evaluated by principal-value and asymptotic techniques, furnishing an explicit solution in Bessel and digamma functions. The variational solution is cast finally into the form of a linear algebraic system, whence we derive various analytic expansions that reproduce further exact results and confirm the efficacy of a simple form of our trial functions. Computations employing this trial function are compared with other approximations and the exact solution. Alternative variational solution representations involving incomplete Anger–Weber or half-range Anger functions are appended.

ISSN:0950-0340    

DOI:10.1080/09500349708230750

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

It has been shown in recent years that incoherent pumping through multiple atomic levels provides a mechanism for the production of highly anti-bunched light, and that as the number of incoherent steps is increased the light becomes increasingly regular. We show that in a resonance fluorescence situation, a multi-level atom may be multiply coherently driven so that the fluorescent light is highly anti-bunched. We show that as the number of coherently driven levels is increased, the spontaneous emissions may be made increasingly more regular. We present a systematic method for designing the level structure and driving required to produce highly anti-bunched light in this manner for an arbitrary even number of levels.

ISSN:0950-0340    

DOI:10.1080/09500349708230751

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

In this paper we present an absolute surface topography measurement with a tuneable diode laser with an external cavity that has a tuning range of as much as 25 nm without mode hops and a very high tuning speed of less than 1 s for the whole range. With this laser, an absolute wavelength-shift speckle pattern interferometer was realized, capable of measuring optically smooth and rough surfaces. We briefly explain the principles of operation, and the importance of wavelength tuning without mode hops. We discuss the capabilities, possible measuring ranges and some results as well as calibration methods of wavelength-shift speckle profilometry.

ISSN:0950-0340    

DOI:10.1080/09500349708230752

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Atom radiation in a squeezedthermalreservoir is studied. We show that, as in the case of a squeezed vacuum reservoir, the two quadratures of the atomic polarization are damped at different rates. When the atom is driven by a coherent field, we find that the steady-state polarization depends on the relative phase of the squeezing and the driving field. However, this phase dependence becomes less pronounced when the number of thermal photons increases. The fluorescent spectrum is calculated in the strong-driving-field limit by employing the secular approximation. Properties of the spectrum and the possibility of a subnatural linewidth are investigated.

ISSN:0950-0340    

DOI:10.1080/09500349708230753

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

An analytic theory of the adiabatic passage (AP) regime of interaction of short frequency chirped laser pulses with a two-level quantum system (QS) being initially in the superpositional quantum state is presented. We show that the initial value of the non-diagonal elements of the density matrix can influence the dynamics of the population transfer during the action of the laser pulse, but do not influence essentially the final populations of the states of the QS obtained at the end of the interaction near the AP regime. A novel solution to the Bloch equations is obtained in the form of a converging power series generalizing the ordinary AP solution.

ISSN:0950-0340    

DOI:10.1080/09500349708230754

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

We investigate a codirectional nonlinear coupler composed of two Kerr nonlinear waveguides. Unlike the conventional device, the linear coupling between the guides is supposed to be a variable function of the propagation distance. We calculate quantum statistical and dynamical properties of the Kerr nonlinear coupler with a coherent input and analyse the influence of coupling variation on oscillations in mean photon number. The possibility to control the switching characteristics and principal squeezing effect by adjusting the form of coupling function is shown.

ISSN:0950-0340    

DOI:10.1080/09500349708230755

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The hybrid optoelectronic processor, presented in this paper, realizes the dual nonlinear correlation (DNC) in a set-up based on a two-step nonlinear joint transform correlator architecture. In the first step three power spectrum distributions (input scene power spectrum, reference target power spectrum, and the joint power spectrum) necessary for the nonlinear processing are captured with a CCD camera. Nonlinear modification of the joint power spectrum, which does not have to be symmetrical in the input and reference channels, is introduced digitally. In the second step, the modified joint power spectrum is Fourier transformed optically. Numerical analysis of this processor shows a crucial influence of the dynamic range and the limited number of grey levels of the CCD camera during image acquisition in the first step, on the output signal parameters and the discrimination capability of the set-up. Optical results of recognition obtained for noise-free segmented input scenes show that the set-up enables the realization of various correlation operations as CMF, POF, IF, PPC, etc. without any filters and that the discrimination capability is easy to control by a proper selection of the type of nonlinear processing.

ISSN:0950-0340    

DOI:10.1080/09500349708230756

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor