EXCITONIC SPIN INSTABILITIES AND CONTINUOUS PHASE TRANSITIONS IN QUANTUM HALL MAGNETS

  • Pellegrini V.
  • Pinczuk A.

Inelastic light scattering from collective excitations has emerged as a powerful tool to explore novel ground states of quantum Hall liquids. We present here a short review of light scattering experiments in coupled electron bilayers in GaAs double quantum wells. At even integer filling factors the bilayers display soft collective ...

Dependence of Gordon-Haus Timing Jitter on the Ratio of the Forward and Backward Pump Powers

  • Mckinstrie C.
  • Mollenauer L.

The Gordon-Haus timing jitter of optical pulses in dispersion- managed communication systems with distributed amplification is studied. The jitter penalty for equal forward and backward pump powers and a pump spacing of 120 Km is 9.3 dB less than the jitter penalty for lumped amplification and an amplifier spacing of ...

Linear codes with exponentially many light vectors

  • Ashikhmin A.
  • Barg A.
  • Vladut S.

G. Kalai and N. Linial (1995) put forward the following conjecture: Let ${C_n}$ be a sequence of binary linear codes of distance $d_n$ and $A_{d_n}$ be the number of vectors of weight $d_n$ in $C_n$, then $log_2 A_{d_n}=o(n).$ We disprove this by constructing a family of linear codes from geometric ...

Strong self-phase modulation in planar chalcogenide glass waveguides

  • Cheong S.
  • Hwang H.
  • Katsufuji T.
  • Lenz G.
  • Slusher R.
  • Spalter S.
  • Zimmermann J.

Single-mode planar waveguides were fabricated from chalcogenide glass compounds with large Kerr nonlinearities. Strong self- phase modulation of sub-ps pulses along with low linear and nonlinear absorption losses demonstrates the potential for ultra-fast, low power, all-optical processing applications.

Cryptographic Key Generation from Voice

  • Li Q.
  • Monrose F.
  • Reiter M.
  • Wetzel S.

We propose a technique to reliably generate a cryptographic key from a user's voice while speaking a password. The key resists cryptanalysis even against an attacker who captures all system information related to generating or verifying the cryptographic key. Moreover, the technique is sufficiently robust to enable the user to ...

The Binding Energy of Vacancy Clusters Generated by High-Energy Ion Implantation and Annealing in Silicon

  • Gossmann H.
  • Haynes T.
  • Pelaz L.
  • Rafferty C.
  • Venezia V.

We have measured the evolution of the excess vacancy region created by a 2 MeV, 1016/cm2 Si implant in the silicon surface layer of silicon-on-insulator substrates. Free vacancy supersaturations were measured with Sb dopant diffusion markers during post- implant annealing at 700, 800, and 900C, while vacancy clusters were detected ...

Beat Interference Penalty in Optical Duplex Transmission

  • Das S.
  • Harstead E.

Optical full duplex transmission refers to simultaneous bi- directional transmission over a single optical fiber without taking any special measures to separate the two signals in the optical or electrical frequency domains. Because of its simplicity and its use of a single fiber, it will be lower in cost than ...

Cayley Differential Unitary Space-Time Codes

  • Hassibi B.
  • Hochwald B.

One method for communicating wih multiple antennas is to differentially encode the transmitted date using unitary matrices at the transmitter, and to differentially decode without knowing the channel coefficients at the receiver. Since channel knowledge is not required at the receiver, differential schemes are ideal for use on wireless links ...

Dispersion Measurement of Tapered Air-Silica Microstructure Fibers by White-Light Interferometry

  • Chandalia J.
  • Digiovanni D.
  • Eggleton B.
  • Knox W.
  • Liu X.
  • Windeler R.
  • Xu C.
  • Ye Q.

Dispersion properties of the novel tapered air-silica microstructure fibers are measured between 1.3 and 1.65 µm by white-light interferometry. Dispersion values (ß2) of -220ps2/km and -164 ps2/km were obtained for 2 mm and 3 mm core sizes, respectively, at ?=1.55 mm.

A Method to Predict the Raman Gain Spectra of Germanosilicate Fibers with Arbitrary Index Profiles

  • Bromage J.
  • Lines M.
  • Rottwitt K.

We present a technique for calculating the Raman gain spectra of germanosilicate fibers from their index profiles. The gain spectra depend on radial profiles of the guided optical modes and the glass composition, in particular, the distribution of Si-O-Si and Ge-O-Si bridging bonds. We have obtained spectral coefficients which represent ...

Refined Asymptotic Solution to an Inverse Problem for a Shared Unbuffered Resource

  • Morrison J.
  • Ramakrishnan K.

We consider an unbuffered resource having capacity C, which is shared by several different services. Calls of each service arrive in a Poisson stream and request a fixed, integral amount of capacity, which depends on the service. An arriving call is blocked and lost if there is not enough free ...

Continuous-wave operation of a 1.3microns GaAsSb/GaAs Quantum-Well Vertical-Cavity Surface-Emitting Laser at Room Temperature

  • Cunningham J.
  • Dinu M.
  • Kilper D.
  • Quochi F.
  • Shah J.

We report continuous-wave, room temperature operation of a GaAsSb/GaAs quantum-well vertical-cavity surface-emitting laser near 1.3microns. The device is pumped with 674 nm light and provides 1 mW total optical output at 1280 nm with 40% differential quantum efficiency. We describe the spatial, angular and spectral properties of the laser. This ...

An Extension of the Positive Real Lemma to Descriptor Systems

  • Freund R.
  • Jarre F.

The well-known positive real lemma characterizes positive realness of transfer functions of time-invariant linear systems via the solvability of certain linear matrix inequalities. In this paper, we propose an extension of the positive real lemma and the underlying linear matrix inequalities to descriptor systems. We show that the solvability of ...

Improving Index Performance through Prefetching

  • Chen S.
  • Gibbons P.
  • Mowry T.

In recognition of the crucial role that cache hierarchies play in database performance, recent studies have revisited core database algorithms and data structures in an effort to reduce the number of cache misses. While these efforts to avoid cache misses are certainly helpful, they are not a complete solution for ...

SI-MMIC BICMOS Low-Noise High-Linearity Amplifiers For Base Station Applications

  • Boric-Lubecke O.
  • Ivanov T.
  • Lin J.
  • Yan R.

Low-noise, high-linearity amplifier chip sets designed for GSM 900 and DCS 1800 base station receivers are reported. The chip sets consisting of LNA and driver amplifier pairs, were fabricated using a 0.25microns silicon BiCMOS process. Noise figures of 1.35 dB and 1.85 dB were achieved for LNA's at 900 MHz ...

Conjugation Length Dependence of the Charge Transport in Oligothiophene Single Crystals

  • Batlogg B.
  • Fichou D.
  • Kloc C.
  • Schon H.

The intrinsic charge transport mechanism in oligothiophene single crystals is investigated by temperature dependent space charge limited current spectroscopy. The mobility for in-plane transport in these layered p-type semiconductors follows a power law behavior typical for coherent bandlike charge transport. A value as high as 80 cm sup 2 /Vs ...

First Demonstration of GaAs CMOS

  • Baillargeon J.
  • Cho A.
  • Hong M.
  • Kwo J.
  • Mannaerts J.

Using Ga sub 2 O sub 3 (Gd sub 2 O sub 3) as a gate dielectric and conventional ion implantation for source, drain, and isolation, we have fabricated and demonstrated a GaAs complementary metal-oxide-semiconductor field-effect-transistor (CMOS) inverter.

New Insights into Many-Body and Correlation Effects in Semiconductors

  • Chemla D.
  • Shah J.

Linear properties of a solid, consisting of 10 sup (22) -10 sup (23) particles/cm sup 3 interacting through infinite-range Coulomb interactions, are well described by the concept of quasi-particles first introduced be Landau. But interactions between quasi-particles, important in all dense systems, are not well understood. Studies over the past ...

Scalable Architecture in Mammalian Brains

  • Clark D.
  • Mitra P.
  • Wang S.

Comparison of mammalian brain parts has often focused on differences in absolute size, revealing only a general tendency for all parts to grow together. One attempt to find size-independent effects uses body weight as a reference variable. However this approach introduces additional variability due to independent growth of the body ...

Sub-picosecond Electron Scattering time for lambda ~ 1.55microns Intersubband Transitions in GaN/AlGaN Multiple Quantum Wells

  • Cho A.
  • Chu S.
  • Frolov S.
  • Gmachl C.
  • Ng H.

We studied GaN/AlGaN multiple quantum wells with a subband spacing of ~ 740 meV (lambda = 1.67microns). Using the time-resolved pump-and-probe technique, with 1.55microns pump and 1.70microns probe wavelength, we measured an intersubband electron scattering time of 370 fs.