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Physics

Optical physics and communications

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Displaying 651 - 675 of 855

Coupled-cavity ring-down spectroscopy technique

August 6, 2012
Author(s)
Jeremie B. Courtois, Joseph T. Hodges
We present a technique called coupled-cavity ring-down spectroscopy (CC-RDS) for controlling the finesse of an optical resonator. Applications include extending the sensitivity and dynamic range of a cavity-enhanced spectrometer, as well as widening the

A compact and robust method for full Stokes spectropolarimetry

August 1, 2012
Author(s)
William Sparks, Thomas Germer, John MacKenty, Frans Snik
We present an approach to spectropolarimetry which requires neither moving parts nor time dependent modulation, and which o ers the prospect of achieving high sensitivity. The concept, which is one of those generically known as channeled polarimetry, is to

On-chip, photon-number-resolving, telecom-band detectors for scalable photonic information processing

July 30, 2012
Author(s)
Thomas Gerrits, Nick Thomas-Peter, James Gates, Adriana E. Lita, Benjamin Metcalf, Brice R. Calkins, Nathan A. Tomlin, Anna E. Fox, Antia A. Lamas-Linares, Justin Spring, Nathan Langford, Richard P. Mirin, Peter Smith, Ian Walmsley, Sae Woo Nam
We demonstrate the operation of an integrated photon number resolving transition edge sensor (TES), operating in the telecom band at 1550 nm, employing an evanescently coupled design that allows the detector to be placed at arbitrary locations within a

An algorithm for finding clusters with a known distribution and its application to photon-number resolution using a superconducting transition-edge sensor

July 20, 2012
Author(s)
Zachary H. Levine, Thomas Gerrits, Alan L. Migdall, Daniel V. Samarov, Brice R. Calkins, Adriana E. Lita, Sae Woo Nam
Improving photon-number resolution of single-photon sensitive detectors is important for many applications, as is extending the range of such detectors. Here we seek improved resolution for a particular Superconducting Transition-Edge Sensor (TES) through

A Glowing Future for Lab on a Chip Testing Standards

June 28, 2012
Author(s)
Samuel M. Stavis
Testing standards are more fundamental from a metrological perspective and less controversial from an industrial perspective than product standards, representing a path of less resistance towards the standardization and commercialization of lab on a chip

Demonstration of Superluminal Images

June 19, 2012
Author(s)
Ryan T. Glasser, Ulrich Vogl, Paul D. Lett
Optical pulse propagation with group velocities larger than the speed of light in vacuum, c, or negative, have been demonstrated theoretically and experimentally in a variety of systems [1–5]. The anomalous dispersion required for generating “fast” light

Calibration of an Astrophysical Spectrograph below 1 m/s using a Laser Frequency Comb

June 4, 2012
Author(s)
David F. Phillips, Alexander G. Glenday, Chih-hao Li, Claire E. Cramer, Gabor Furesz, Guoquing Chang, Andrew Benedick, Li-Jin Chen, F X. Kaertner, Sylvain G. Korzennik, Dimitar Sasselov, Andrew Szentgyorgyi, Ronald L. Walsworth
We deployed two wavelength calibrators based on laser frequency combs ("astro-combs") at an astronomical observatory. One astro-comb operated over a 100 nm band in the deep red ( 800 nm) and a second operated over a 20 nm band in the blue ( 400 nm). We

Exotic behavior in quantum dot mode-locked lasers: dark pulses and bistability

May 24, 2012
Author(s)
Kevin L. Silverman, Mingming M. Feng, Richard P. Mirin, Steven T. Cundiff
Passively mode-locked semiconductor lasers with self-assembled quantum dot active regions can be operated in exotic output modes, stabilized by the complex gain and absorption dynamics inherent in these structures. One such device emits dark pulses - sharp

Frequency characterization of a swept and fixed-wavelength external-cavity quantum cascade laser by use of a frequency comb

May 21, 2012
Author(s)
Kevin O. Knabe, Paul A. Williams, Fabrizio R. Giorgetta, Chris Armacost, Michael Radunsky, Nathan R. Newbury
The instantaneous optical frequency of an external-cavity quantum cascade laser (QCL) is characterized by comparison to a near-infrared frequency comb. Fluctuations in the instantaneous optical frequency are analyzed to determine the frequency noise power

Ultra-Small-Angle X-ray Scattering-X-ray Photon Correlation Spectroscopy: A New Measurement Technique for in-situ Studies of Equilibrium and Nonequilibrium Dynamics

May 1, 2012
Author(s)
Fan Zhang, Andrew J. Allen, Lyle E. Levine, Jan Ilavsky, Gabrielle G. Long
Ultra-small-angle X-ray scattering—X-ray photon correlation spectroscopy (USAXS-XPCS) is a novel measurement technique for the study of equilibrium and slow nonequilibrium dynamics in disordered materials. This technique fills an existing gap between the

Stimulated Generation of Superluminal Light Pulses via Four-wave Mixing

April 26, 2012
Author(s)
Ryan T. Glasser, Ulrich Vogl, Paul D. Lett
We report on the four-wave mixing of superluminal pulses, in which both the injected and generated pulses involved in the process propagate with negative group velocities. Generated pulses with negative group velocities of up to vg = −c/880 are

Frequency-stabilized cavity ring-down spectroscopy

March 21, 2012
Author(s)
David A. Long, A. Cygan, Roger D. van Zee, Mitchio Okumura, C. E. Miller, D Lisak, Joseph T. Hodges
This Frontiers article describes frequency-stabilized cavity ring-down spectroscopy (FS-CRDS), an ultraprecise refinement of conventional cw-CRDS. We review the technique and highlight some recent studies which have utilized FS-CRDS to perform precision

Differential matrices for depolarizing media

March 1, 2012
Author(s)
Thomas A. Germer
The evolution of a Stokes vector through depolarizing media is considered. A general form for the differential matrix is derived that is appropriate in the presence of depolarization, and is parameterized in a manner that ensures that it yields, upon

An atomic interface between microwave and optical photons

February 22, 2012
Author(s)
Mohammad Hafezi, Zaeill Kim, Steven L. Rolston, Luis A. Orozco, Benjamin Lev, Jacob M. Taylor
A complete physical approach to quantum information requires a robust interface among flying qubits, long-lifetime memory and computational qubits. Here we present a unified interface for microwave and optical photons, potentially connecting engineerable

Optimization of the TES-bias circuit for a multiplexed microcalorimeter array

January 27, 2012
Author(s)
William B. Doriese, Bradley K. Alpert, Joseph W. Fowler, Gene C. Hilton, Alex S. Hojem, Kent D. Irwin, Carl D. Reintsema, Daniel R. Schmidt, Greg Stiehl, Daniel S. Swetz, Joel N. Ullom, Leila R. Vale
In the detector-bias circuit of a transition-edge-sensor (TES) microcalorimeter, the TES-shunt resistor (Rsh) and the thermal conductance to the cryogenic bath (G) are often considered to be interchangeable knobs with which to control detector speed

Probing the timescale of the exchange interaction in a ferromagnetic alloy

January 27, 2012
Author(s)
Justin M. Shaw, Stefan Mathias, Chan La-O-Vorakiat, Hans T. Nembach, Thomas J. Silva, Mark Siemens, Henry Kapteyn, Margaret Murnane
The underlying physics of all ferromagnetic behavior is the cooperative interaction between individual atomic magnetic moments that results in a macroscopic magnetization. In this work, we use extreme ultraviolet pulses from high-harmonic generation as an

Standards for the Optical Detection of Protein Particulates

January 23, 2012
Author(s)
Dean C. Ripple, Michael J. Carrier, Joshua R. Wayment
Particulates in protein therapeutics, composed of agglomerated protein monomers, may cause an immunogenic response in patients. Consequently, industry and the FDA desire more accurate methods for counting and characterizing particulates. Unlike likely
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