11 research outputs found
Miniature optical delay lines and buffers
Creation of miniature optical delay lines and buffers is one of the greatest challenges of the modern photonics which can revolutionize optical communications and computing. Several remarkable designs of slow light optical delay lines employing coupled ring resonators and photonic crystal waveguides has been suggested and experimentally demonstrated. However, the insertion loss of these devices is too large for their practical applications. Alternatively, the recently developed photonic fabrication platform, Surface Nanoscale Axial Photonics (SNAP) allows us to fabricate record small delay lines with unprecedentedly small dispersion and low loss. In this report, we review the recent progress in fabrication and design of miniature slow light devices and buffers, in particular, those based on the SNAP technology
Feasibility study of beam-expanding telescopes in the interferometer arms for the Einstein Telescope
The optical design of the Einstein Telescope (ET) is based on a dual-recycled
Michelson interferometer with Fabry-Perot cavities in the arms. ET will be
constructed in a new infrastructure, allowing us to consider different
technical implementations beyond the constraints of the current facilities. In
this paper we investigate the feasibility of using beam-expander telescopes in
the interferometer arms. We provide an example implementation that matches the
optical layout as presented in the ET design update 2020. We further show that
the beam-expander telescopes can be tuned to compensate for mode mismatches
between the arm cavities and the rest of the interferometer.Comment: 9 pages with 11 figures. To be published in: PR
Precise optical characterization of SNAP structures with a reference fiber
A method of precise characterization of surface nanoscale axial photonics (SNAP) structures with a reference fiber is proposed, analyzed, and demonstrated experimentally. The method is based on simultaneous coupling of a microfiber to a SNAP structure under test and to a reference optical fiber. Significant reduction of measurement errors associated with the environmental temperature variations and technical noise of the spectrum analyzer is demonstrated. The achieved measurement precision of the effective radius variation of the SNAP structure is 0.2 Å
First results of the Laser-Interferometric Detector for Axions (LIDA)
We present the operating principle and the first observing run of a novel
kind of direct detector for axions and axion-like particles in the galactic
halo. Our experiment is sensitive to the polarisation rotation of linearly
polarised laser light induced by an axion field, and the first detector of its
kind collecting science data. We discuss our current peak sensitivity of
GeV (95 % confidence level) to the axion-photon
coupling strength in the axion mass range of 1.97-2.01 neV which is, for
instance, motivated by supersymmetric grand-unified theories. We also report on
effects that arise in our high-finesse in-vacuum cavity at unprecedented
optical continuous-wave intensity. Our detector already belongs to the most
sensitive direct searches within its measurement band, and our first results
pave the way towards surpassing the current sensitivity limits in the mass
range from eV down to eV via quantum-enhanced laser
interferometry
Design and sensitivity of a 6-axis seismometer for gravitational wave observatories
We present the design, control system, and noise analysis of a 6-axis
seismometer comprising a mass suspended by a single fused silica fibre. We
utilise custom-made, compact Michelson interferometers for the readout of the
mass motion relative to the table and successfully overcome the sensitivity of
existing commercial seismometers by over an order of magnitude in the angular
degrees of freedom. We develop the sensor for gravitational-wave observatories,
such as LIGO, Virgo, and KAGRA, to help them observe intermediate-mass black
holes, increase their duty cycle, and improve localisation of sources. Our
control system and its achieved sensitivity makes the sensor suitable for other
fundamental physics experiments, such as tests of semiclassical gravity,
searches for bosonic dark matter, and studies of the Casimir force
Design of a tabletop interferometer with quantum amplification
The sensitivity of laser interferometers is fundamentally limited by the
quantum nature of light. Recent theoretical studies have opened a new avenue to
enhance their quantum-limited sensitivity by using active parity-time-symmetric
and phase-insensitive quantum amplification. These systems can enhance the
signal response without introducing excess noise in the ideal case. However,
such active systems must be causal, stable, and carefully tuned to be practical
and applicable to precision measurements. In this paper, we show that
phase-insensitive amplification in laser interferometers can be implemented in
a tabletop experiment. The layout consists of two coupled cavities and an
active medium comprised of a silicon nitride membrane and an auxiliary pump
field. Our design relies on existing membrane and cryogenic technology and can
demonstrate three distinct features: (i) the self-stabilized dynamics of the
optical system, (ii) quantum enhancement of its sensitivity in the presence of
the amplifier, and (iii) optical control of the amplifier gain. These features
are needed to enhance the sensitivity of future interferometric
gravitational-wave and axion detectors.Comment: 8 pages, 5 figure
Two Novel Lytic Bacteriophages Infecting <i>Enterococcus</i> spp. Are Promising Candidates for Targeted Antibacterial Therapy
The rapid emergence of antibiotic resistance is of major concern globally. Among the most worrying pathogenic bacteria are vancomycin-resistant enterococci. Phage therapy is a highly promising method for controlling enterococcal infections. In this study, we described two virulent tailed bacteriophages possessing lytic activity against Enterococcus faecalis and E. faecium isolates. The SSsP-1 bacteriophage belonged to the Saphexavirus genus of the Siphoviridae family, and the GVEsP-1 bacteriophage belonged to the Schiekvirus genus of Herelleviridae. The genomes of both viruses carried putative components of anti-CRISPR systems and did not contain known genes coding for antibiotic-resistance determinants and virulence factors. The conservative arrangement of protein-coding sequences in Saphexavirus and Schiekvirus genomes taken together with positive results of treating enterococcal peritonitis in an animal infection model imply the potential suitability of GVEsP-1 and SSsP-1 bacteriophages for clinical applications
A Genome of Temperate <i>Enterococcus</i> Bacteriophage Placed in a Space of Pooled Viral Dark Matter Sequences
In the human gut, temperate bacteriophages interact with bacteria through predation and horizontal gene transfer. Relying on taxonomic data, metagenomic studies have associated shifts in phage abundance with a number of human diseases. The temperate bacteriophage VEsP-1 with siphovirus morphology was isolated from a sample of river water using Enterococcus faecalis as a host. Starting from the whole genome sequence of VEsP-1, we retrieved related phage genomes in blastp searches of the tail protein and large terminase sequences, and blastn searches of the whole genome sequences, with matches compiled from several different databases, and visualized a part of viral dark matter sequence space. The genome network and phylogenomic analyses resulted in the proposal of a novel genus “Vespunovirus”, consisting of temperate, mainly metagenomic phages infecting Enterococcus spp
Open data from the first and second observing runs of Advanced LIGO and Advanced Virgo
Advanced LIGO and Advanced Virgo are monitoring the sky and collecting gravitational-wave strain data with sufficient sensitivity to detect signals routinely. In this paper we describe the data recorded by these instruments during their first and second observing runs. The main data products are gravitational-wave strain time series sampled at 16384 Hz. The datasets that include this strain measurement can be freely accessed through the Gravitational Wave Open Science Center at http://gw-openscience.org, together with data-quality information essential for the analysis of LIGO and Virgo data, documentation, tutorials, and supporting software