102 research outputs found
Analytic spatial and temporal temperature profile in a finite laser rod with input laser pulses
In this communication, we present an analytic expression of the thermal load in a cylindrical laser rod. We consider a pump beam with Gaussian temporal and spatial profile, which permits, using superposition of the single pulse solution, an explicit calculation of the optical path length difference across the radial direction of the rod and of the transient thermal focal length changes for a variable pump repetition rate and pulse width. We have chosen to model Ti:A_l2O_3 as a specific example, however our solution is completely general and can be applied to any materials with cylindrical geometry employing a stable laser cavity design
Astronomy\u27s New Messengers: A Traveling Exhibit to Reach Out to a Young Adult Audience
The Laser Interferometer Gravitational-wave Observatory exhibit Astronomy\u27s New Messengers: Listening to the Universe with Gravitational Waves is traveling to colleges, universities, museums and other public institutions throughout the United States. In 2010, an extended version of this exhibit will appear in a New York City venue that is accessible to a large and diverse cross section of the general public. Astronomy\u27s New Messengers primarily communicates with an adolescent and young adult audience, potentially inspiring them into the field of science. Acknowledging that this audience is traditionally a difficult one to attract, the exhibit publicly announces itself in a charismatic fashion to reach its principal goals of broadening the community of people interested in science and encouraging interest in science among young people
Astronomy\u27s New Messengers: A Traveling Exhibit on Gravitational-Wave Physics
The Laser Interferometer Gravitational-wave Observatory exhibit Astronomy\u27s New Messengers: Listening to the Universe with Gravitational Waves is traveling to colleges, universities, museums and other public institutions throughout the United States. Astronomy\u27s New Messengers primarily communicates with an adolescent and young adult audience, potentially inspiring them into the field of science. Acknowledging that this audience is traditionally a difficult one to attract, the exhibit publicly announces itself in a charismatic fashion to reach its principal goals of broadening the community of people interested in science and encouraging interest in science among young people
Sensing and control in dual-recycling laser interferometer gravitational-wave detectors
We introduce length-sensing and control schemes for the dual-recycled cavity-enhanced Michelson interferometer configuration proposed for the Advanced Laser Interferometer Gravitational Wave Observatory (LIGO). We discuss the principles of this scheme and show methods that allow sensing and control signals to be derived. Experimental verification was carried out in three benchtop experiments that are introduced. We present the implications of the results from these experiments for Advanced LIGO and other future interferometric gravitational-wave detectors
Census of the Local Universe (CLU) Narrow-Band Survey I: Galaxy Catalogs from Preliminary Fields
We present the Census of the Local Universe (CLU) narrow-band survey to
search for emission-line (\ha) galaxies. CLU-\ha~has imaged 3 of
the sky (26,470~deg) with 4 narrow-band filters that probe a distance out
to 200~Mpc. We have obtained spectroscopic follow-up for galaxy candidates in
14 preliminary fields (101.6~deg) to characterize the limits and
completeness of the survey. In these preliminary fields, CLU can identify
emission lines down to an \ha~flux limit of
~ at 90\% completeness, and recovers 83\%
(67\%) of the \ha~flux from catalogued galaxies in our search volume at the
=2.5 (=5) color excess levels. The contamination from galaxies
with no emission lines is 61\% (12\%) for =2.5 (=5). Also, in
the regions of overlap between our preliminary fields and previous
emission-line surveys, we recover the majority of the galaxies found in
previous surveys and identify an additional 300 galaxies. In total, we
find 90 galaxies with no previous distance information, several of which are
interesting objects: 7 blue compact dwarfs, 1 green pea, and a Seyfert galaxy;
we also identified a known planetary nebula. These objects show that the
CLU-\ha~survey can be a discovery machine for objects in our own Galaxy and
extreme galaxies out to intermediate redshifts. However, the majority of the
CLU-\ha~galaxies identified in this work show properties consistent with normal
star-forming galaxies. CLU-\ha~galaxies with new redshifts will be added to
existing galaxy catalogs to focus the search for the electromagnetic
counterpart to gravitational wave events.Comment: 28 pages, 22 figures, 4 tables (Accepted to ApJ
High-vacuum-compatible high-power Faraday isolators for gravitational-wave interferometers
Faraday isolators play a key role in the operation of large-scale gravitational-wave detectors. Second-generation gravitational-wave interferometers such as the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and Advanced Virgo will use high-average-power cw lasers (up to 200 W) requiring specially designed Faraday isolators that are immune to the effects resulting from the laser beam absorption–degraded isolation ratio, thermal lensing, and thermally induced beam steering. In this paper, we present a comprehensive study of Faraday isolators designed specifically for high-performance operation in high-power gravitational-wave interferometers
Giant Superfluorescent Bursts from a Semiconductor Magnetoplasma
Currently, considerable resurgent interest exists in the concept of
superradiance (SR), i.e., accelerated relaxation of excited dipoles due to
cooperative spontaneous emission, first proposed by Dicke in 1954. Recent
authors have discussed SR in diverse contexts, including cavity quantum
electrodynamics, quantum phase transitions, and plasmonics. At the heart of
these various experiments lies the coherent coupling of constituent particles
to each other via their radiation field that cooperatively governs the dynamics
of the whole system. In the most exciting form of SR, called superfluorescence
(SF), macroscopic coherence spontaneously builds up out of an initially
incoherent ensemble of excited dipoles and then decays abruptly. Here, we
demonstrate the emergence of this photon-mediated, cooperative, many-body state
in a very unlikely system: an ultradense electron-hole plasma in a
semiconductor. We observe intense, delayed pulses, or bursts, of coherent
radiation from highly photo-excited semiconductor quantum wells with a
concomitant sudden decrease in population from total inversion to zero. Unlike
previously reported SF in atomic and molecular systems that occur on nanosecond
time scales, these intense SF bursts have picosecond pulse-widths and are
delayed in time by tens of picoseconds with respect to the excitation pulse.
They appear only at sufficiently high excitation powers and magnetic fields and
sufficiently low temperatures - where various interactions causing decoherence
are suppressed. We present theoretical simulations based on the relaxation and
recombination dynamics of ultrahigh-density electron-hole pairs in a quantizing
magnetic field, which successfully capture the salient features of the
experimental observations.Comment: 21 pages, 4 figure
The Advanced LIGO Input Optics
The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design
The advanced LIGO input optics
The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design
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