Have you ever felt that the very title, Progress in Optics, conjured an image in your mind? Don’t you see a row of handsomely printed books, bearing the editorial stamp of one of the most brilliant members of the optics community, and chronicling the field of optics since the invention of the laser? If so, you are certain to move the bookend to make room for Volume 16, the latest of this series. It contains seven chapters on widely diverging topics, written by well-known authorities in their fields. These are: 1) Laser Selective Photophysics and Photochemistry by V. S. Letokhov, 2) Recent Advances in Phase Profiles (sic) Generation by J. J. Clair and C. I. Abitbol, 3 ) Computer-Generated Holograms: Techniques and Applications by W.-H. Lee, 4) Speckle Interferometry by A. E. Ennos, 5 ) Deformation  Invariant, Space-Variant Optical  Pattern Recognition by D. Casasent and D. Psaltis, 6) Light Emission from High-Current Surface-Spark Discharges by R. E. Beverly, and 7) Semiclassical Radiation  Theory within a  QuantumMechanical Framework by I. R. Senitzkt. The  breadth of topic  matter  spanned  by  these  chapters makes it impossible, for this reviewer at least, to pass judgement on the comprehensiveness, relevance, and completeness of every chapter. With an editorial board as prominent as that of Progress in Optics, however, it seems hardly likely that such comments should be necessary. It should certainly be possible to take the authority of each author as credible. The only remaining judgment to be  made on these chapters is their readability. In short, what are they like to read? The first sentence of the first chapter greets the eye with an obvious typographical error: “The creation of coherent laser light source, that have tunable radiation, opened the . . . .” Two pages later we find: “When two types of atoms or molecules of different isotopic composition ( A and B ) have even one spectral line that does not overlap with others, it is pos-

Progress in optics

「Science」與「Nature」之科學計量分析

We theoretically investigate the simultaneous formation and stable propagation of slow optical soliton pairs in semiconductor quantum dots with a four-level biexciton-exciton cascade configuration. Owing to the destructive interference set up by two continuous wave control fields that couple to a biexciton state, the linear as well as nonlinear dispersion can be dramatically enhanced simultaneously with the absorptions of two weak probe fields being almost suppressed. These results reveal that the detrimental distortions of the two weak-pulsed probe fields due to dispersion effects can be well balanced by the self-phase modulation effect under very low input light intensity, which leads to the slow temporal optical soliton pairs with matched group velocity and amplitude. We also show that the propagation of slow optical solitons can be strongly modified by the biexciton coherence.

/pdf/matched-slow-optical-soliton-pairs-via-biexciton-coherence-21ud669f7b.pdf

Matched slow optical soliton pairs via biexciton coherence in quantum dots

Dense coding and teleportation with one-dimensional cluster states

We develop simple density-matrix models to describe the role of coherence in resonant-tunneling (RT) transport of quantum-cascade lasers (QCLs). Specifically, we investigate the effects of coherent coupling between the lasing levels with other levels on the transport properties and gain spectra. In the first part of the paper, we use a three-level density-matrix model to obtain useful analytical expressions for current transport through the injector barrier in a QCL. An expression for the slope discontinuity in the current-voltage characteristics at the lasing threshold is derived. This value is shown to be a direct measure of the population inversion at threshold and contradicts the previously held belief of it being indicative of ratio of the laser level lifetimes. In the second part of the paper, we use density matrices to compute the gain spectrum for a resonant-phonon terahertz QCL design. The large anticrossing of the doublet of lower radiative levels is reflected in a broad gain linewidth due to a coherent RT assisted depopulation process. At certain bias conditions, the gain spectrum exhibits double peaks which is supported by experimental observations.

Coherence of resonant-tunneling transport in terahertz quantum-cascade lasers

We study the low-intensity light pulse propagation through an asymmetric double quantum well via Fano-type interference based on intersubband transitions. The propagation of the pulse across the quantum well is studied analytically and numerically with the coupled Maxwell-Schr\"odinger equations. We show the generation of ultraslow bright and dark optical solitons in this system. Whether the solitons are dark and bright can be controlled by the ratio of dipole moments of the intersubband transitions. Such investigation of ultraslow optical solitons in the present work may lead to important applications such as high-fidelity optical delay lines and optical buffers in semiconductor quantum wells structure.

/pdf/ultraslow-bright-and-dark-solitons-in-semiconductor-quantum-4qavp06n4z.pdf

Ultraslow bright and dark solitons in semiconductor quantum wells

In this paper, based on the recent experiment by Roos [Science 304, 1478 (2004)], a theoretical scheme is proposed to create the multipartite entanglement of many trapped ions and implement a two-qubit quantum phase gate between two ions in ion trap. In the scheme, the ion is illuminated by a single laser tuned to the first lower vibrational sideband. We also show that the scheme can be used to directly transfer information between two ions. The scheme has the advantage that it does not use the vibrational mode as the data bus and only requires a single resonant interaction. Thus the scheme is very simple and the quantum dynamics operation can be realized at a high speed. In view of the decoherence mechanism, the simplification for the entangled state preparation and experimental implementation of quantum logic operation may become crucial.

Efficient scheme for multipartite entanglement and quantum information processing with trapped ions

We show the formation of bright and dark slow optical solitons based on intersubband transitions in a semiconductor quantum well (SQW). Using the coupled Schrodinger-Maxwell approach, we provide both analytical and numerical results. Such a nonlinear optical process may be used for the control technology of optical delay lines and optical buffers in the SQW solid-state system. With appropriate parameters, we also show the generation of a large cross-phase modulation (XPM). Since the intersubband energy level can be easily tuned by an external bias voltage, the present investigation may open possibilities for electrically controlled phase modulators in solid systems.

http://mx.nthu.edu.tw/~rklee/files/0803.1886-slow-soliton.pdf

Slow optical solitons via intersubband transitions in a semiconductor quantum well

By analyzing the nonlinear optical response in an asymmetric coupled double quantum well structure based on the intersubband transitions, we show that a giant Kerr nonlinearity with a relatively large cross-phase modulation coefficient can be used to produce efficient photonphoton entanglement and implement an all-optical two-qubit quantum polarization phase gate. We also demonstrate that such photon-photon entanglement is practically controllable and may facilitate more practical applications in all-optical quantum information and computation.

http://mx.nthu.edu.tw/~rklee/files/OE-08-phase-gate.pdf

Controllable entanglement and polarization phase gate in coupled double quantum-well structures.

We perform a time-dependent analysis of continuous wave (cw) four-wave mixing (FWM) in InGaAs/AlAs coupled double quantum well (CDQW) structures via intersubband transitions. By using the coupled Schrodinger-Maxwell approach, we obtain the corresponding explicit analytical expressions for the input probe and FWM-generated signal fields. We calculated the dependencies of the efficiency of the FWM-generated fields on cw pump fields and the depths of penetration into the CDQW sample. Such a nonlinear optical process may be used to generate coherent short-wavelength radiation efficiently in the CDQW solid state system.

/pdf/highly-efficient-four-wave-mixing-via-intersubband-3hur7cnf8s.pdf

Wen-Xing Yang

Papers

Ultraslow bright and dark solitons in semiconductor quantum wells

Efficient scheme for multipartite entanglement and quantum information processing with trapped ions

Slow optical solitons via intersubband transitions in a semiconductor quantum well

Controllable entanglement and polarization phase gate in coupled double quantum-well structures.

Highly efficient four-wave mixing via intersubband transitions in InGaAs/AlAs coupled double quantum well structures