摘要:

The quantum state diffusion model of open systems provides a practical tool for the description of the evolution of individual systems. In this letter we present the Heisenberg picture of this model and use it to compute arbitrary multi-time expectation values. In this way we extend the computational power of the model.

ISSN:0950-0340    

DOI:10.1080/09500349314552331

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A high reflectivity broad-band SBN : Ce phase conjugator with an external ring cavity in the near infrared wavelength region, 706 to 830 nm, is reported. Phase conjugation reflectivity was measured to be greater than 60% in the wavelength region, 706-820 nm, and as high as 67% at 716 nm. To our knowledge, this is the highest phase conjugation reflectivity by a SBN : Ce self-pumped phase conjugator. Both c.w. and square-wave pump sources were used. No significant changes of the phase conjugation reflectivity were observed when the pump source was changed from c.w. to a square wave at each different wavelength. The wave form of the phase conjugate wave follows the pump square wave. The build-up time of the phase conjugate wave under a square-wave pump was found to be twice that under a c.w. pump when the peak power of the square wave was the same as the power of the c.w. beam.

ISSN:0950-0340    

DOI:10.1080/09500349314552341

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Synthesis of a sharp switching characteristic is experimentally demonstrated by concatenation of nonlinear optical loop mirrors. A novel configuration has been used which results in three terminal operation of the device. This device can be used as a logic gate and for pulse shaping to produce square pulses.

ISSN:0950-0340    

DOI:10.1080/09500349314552351

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The time evolution of the atomic dipole moment of a two-level atom damped by an off-resonance squeezed vacuum is studied. Our results are valid for arbitrary detuning between the carrier frequency of the squeezed vacuum and the atomic transition frequency and show that the atomic dipole moment can oscillate with two dominant frequencies. These frequencies are shifted from their central values by an amount which is proportional to the degree of squeezing. We show that this shift of the frequencies is the exact equivalent of the optical Bloch-Siegert shift in the case of the ordinary vacuum damping without the rotating-wave approximation.

ISSN:0950-0340    

DOI:10.1080/09500349314552361

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The influence of the dipole-dipole interaction on the final atomic state of a two-atom system driven by a coherent laser field and damped by a broad-band squeezed vacuum is discussed. It is shown that in the absence of a coherent laser field the final atomic state is independent of the dipole-dipole interaction and can be the pure two-atom squeezed state only if detuning of the squeezed vacuum field from atomic resonance is equal to zero. In the presence of a coherent laser field, the final atomic state depends on the dipole-dipole interaction. As the latter increases, the final atomic state shifts from a mixed state to the pure two-atom squeezed state. However, this happens only if the driving field and the squeezed field frequencies are tuned to the atomic transition frequency. For the driving field and the squeezed vacuum field frequencies detuned from atomic resonance the system decays into a mixed state irrespective of the dipole-dipole interaction between the atoms.

ISSN:0950-0340    

DOI:10.1080/09500349314552371

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

We study the properties of quantum states of the electromagnetic field obtained from the application of the squeeze operator to superpositions of the ordinary coherent states ¦α> and ¦−α>.

ISSN:0950-0340    

DOI:10.1080/09500349314552381

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

We use the recently-established asymptotic solution (AS) for large fields to study squeezing in the Jaynes-Cummings model. Arbitrary initial atomic states (including atomic coherence) are considered. We find that most features of squeezing can be understood from the properties of the asymptotic field states, and from the observation, which we establish numerically, that for large fields the interference between the two branches of the wavefunction does not contribute significantly to the squeezing (not even near the revival times, when the two field states being superposed have very nearly the same phase). We obtain a limit on the time over which the field may show any squeezing and find that it scales as the 3/4 power of the number of photons. We also obtain a bound on the maximum achievable squeezing for a given number of photons, which is an improvement over earlier estimates. Finally, we discuss some of the shortcomings of the AS, and in particular the existence of a small ghost peak in the fieldQfunction for initial conditions where the AS predicts a single peak, which is enough to destroy the squeezing for certain times.

ISSN:0950-0340    

DOI:10.1080/09500349314552391

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

We present a new approach for simulating time-evolving speckle patterns, by combining the shift of a rigid phase screen with its evolution. Thus, the two time-scales associated with speckle boiling and speckle motion can be adjusted independently. The statistical properties of the phase perturbation and the speckle pattern are investigated by using the temporal phase structure function and the temporal intensity correlation. We found a very good agreement with experimental results.

ISSN:0950-0340    

DOI:10.1080/09500349314552401

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A method to obtain in real-time contour maps of equal slope on a three-dimensional surface is described. The performance of the method is significantly improved by selective modification of phase differences in the interferometer. The sensitivity of the method can be tuned in a wide range. Phase-shifting procedures can be applied to the technique for quantitative measurement purposes.

ISSN:0950-0340    

DOI:10.1080/09500349314552411

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Using the asymptotic form of the density matrix the role of the non-diagonal elements of the density matrix is estimated in the lossless micromaser model based on the Jaynes-Cummings model with intensity dependent coupling constant. It is shown that a certain type of a (almost pure) multiphoton state can be generated in this system.

ISSN:0950-0340    

DOI:10.1080/09500349314552421

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor