arXiv subjects

D. Feldbaum

Publications and source records attributed to D. Feldbaum.

7 recordsLinked to original sources

arXiv2016

Small optic suspensions for Advanced LIGO input optics and other precision optical experiments

We report on the design and performance of small optic suspensions developed to suppress seismic motion of out-of-cavity optics in the Input Optics subsystem of the Advanced LIGO interferometric gravitational wave detector. These compact single stage suspensions provide isolation in all six degrees of freedom of the optic, local sensing and actuation in three of them, and passive damping for the other three.

physics.ins-det↗

arXiv2016

The Sensitivity of the Advanced LIGO Detectors at the Beginning of Gravitational Wave Astronomy

The Laser Interferometer Gravitational Wave Observatory (LIGO) consists of two widely separated 4 km laser interferometers designed to detect gravitational waves from distant astrophysical sources in the frequency range from 10 Hz to 10 kHz. The first observation run of the Advanced LIGO detectors started in September 2015 and ended in January 2016. A strain sensitivity of better than $10^{-23}/\sqrt{\text{Hz}}$ was achieved around 100 Hz. Understanding both the fundamental and the technical noise sources was critical for increasing the observable volume in the universe. The average distance at which coalescing binary black hole systems with individual masses of 30 $M_\odot$ could be detected was 1.3 Gpc. Similarly, the range for binary neutron star inspirals was about 75 Mpc. With respect to the initial detectors, the observable volume of Universe increased respectively by a factor 69 and 43. These improvements allowed Advanced LIGO to detect the gravitational wave signal from the binary black hole coalescence, known as GW150914.

astro-ph.IM↗

arXiv2011

Characterization of thermal effects in the Enhanced LIGO Input Optics

We present the design and performance of the LIGO Input Optics subsystem as implemented for the sixth science run of the LIGO interferometers. The Initial LIGO Input Optics experienced thermal side effects when operating with 7 W input power. We designed, built, and implemented improved versions of the Input Optics for Enhanced LIGO, an incremental upgrade to the Initial LIGO interferometers, designed to run with 30 W input power. At four times the power of Initial LIGO, the Enhanced LIGO Input Optics demonstrated improved performance including better optical isolation, less thermal drift, minimal thermal lensing and higher optical efficiency. The success of the Input Optics design fosters confidence for its ability to perform well in Advanced LIGO.

physics.ins-det↗

arXiv2007

Trapping radioactive ^{82}Rb in an optical dipole trap and evidence of spontaneous spin polarization

Optical trapping of selected species of radioactive atoms has great potential in precision measurements for testing fundamental physics such as EDM, PNC and parity violating beta-decay asymmetry correlation coefficients. We report trapping of 10^4 radioactive ^{82}Rb atoms (t_{1/2}=75 s) with a trap lifetime of ~55 seconds in an optical dipole trap. Transfer efficiency from the magneto-optical trap was ~14%. We further report the evidence of spontaneous spin polarization of the atoms in optical dipole trap loading. This advancement is an important step towards a new generation of precision J-beta correlations measurements with polarized ^{82}Rb atoms.

quant-ph↗

arXiv2003

Autler-Townes spectroscopy of the $5S_{1/2}-5P_{3/2}-44D$ cascade of cold $^{85}$Rb atoms

We study nonlinear optical effects in the laser excitation of Rydberg states. $5S_{1/2}$ and $5P_{3/2}$ levels of $^{85}$Rb are strongly coupled by a strong laser field and probed by a weak laser tuned to the $5P_{3/2} - 44D$ Rydberg resonance. We observe high contrast Autler-Townes spectra which are dependent on the pump polarization, intensity and detuning. The observed behavior agrees with calculations, which include the effect of optical pumping.

quant-ph↗

arXiv2000

Spectroscopic electric-field measurement in laser-excited plasmas

The electric field in mm-sized clouds of cold Rb^+-ions is measured using the Stark effect of Rydberg atoms embedded in the ion clouds. The ion clouds are produced by UV photoionization of laser-cooled rubidium atoms in a magneto-optic trap. In very dense ion clouds, the Rydberg atom excitation spectra reflect the presence of a neutral plasma core and a positively charged ion shell.

physics.atom-ph↗

arXiv2000

The ZEKE-effect in cold Rydberg gases

Cold, dense Rydberg gases produced in a cold-atom trap are investigated using spectroscopic methods and time-resolved electron counting. On the discrete Rydberg resonances we observe large trap losses and long lasting electron emission from the Rydberg gas (>30ms). Our observations are explained by quasi-elastic l-mixing collisions between Rydberg atoms and slow electrons that lead to the population of long-lived high-angular-momentum Rydberg states. These atoms thermally ionize slowly and with large probabilities, leading to the observed effects.

physics.atom-ph↗