1,872 research outputs found
High-bandwidth squeezed light at 1550 nm from a compact monolithic PPKTP cavity
We report the generation of squeezed vacuum states of light at 1550 nm with a
broadband quantum noise reduction of up to 4.8 dB ranging from 5 MHz to 1.2 GHz
sideband frequency. We used a custom-designed 2.6 mm long biconvex
periodically-poled potassium titanyl phosphate (PPKTP) crystal. It featured
reflectively coated end surfaces, 2.26 GHz of linewidth and generated the
squeezing via optical parametric amplification. Two homodyne detectors with
different quantum efficiencies and bandwidths were used to characterize the
non-classical noise suppression. We measured squeezing values of up to 4.8 dB
from 5 to 100 MHz and up to 3 dB from 100 MHz to 1.2 GHz. The squeezed vacuum
measurements were limited by detection loss. We propose an improved detection
scheme to measure up to 10 dB squeezing over 1 GHz. Our results of GHz
bandwidth squeezed light generation provide new prospects for high-speed
quantum key distribution.Comment: 8 pages, 4 figure
Gaussian entanglement distribution with gigahertz bandwidth
The distribution of entanglement with Gaussian statistic can be used to
generate a mathematically-proven secure key for quantum cryptography. The
distributed secret key rate is limited by the {entanglement strength, the
entanglement bandwidth and the bandwidth of the photo-electric detectors}. The
development of a source for strongly, bi-partite entangled light with high
bandwidth promises an increased measurement speed and a linear boost in the
secure data rate. Here, we present the experimental realization of a Gaussian
entanglement source with a bandwidth of more than 1.25\,GHz. The entanglement
spectrum was measured with balanced homodyne detectors and was quantified via
the inseparability criterion introduced by Duan and coworkers with a critical
value of 4 below which entanglement is certified. Our measurements yielded an
inseparability value of about 1.8 at a frequency of 300\,MHz to about 2.8 at
1.2\,GHz extending further to about 3.1 at 1.48\,GHz. In the experiment we used
two 2.6\,mm long monolithic periodically poled potassium titanyl phosphate
(PPKTP) resonators to generate two squeezed fields at the telecommunication
wavelength of 1550\,nm. Our result proves the possibility of generating and
detecting strong continuous-variable entanglement with high speed.Comment: 5 pages, 3 figures, published in Optics Letter
The squeezed light source for the advanced virgo detector in the observation run O3
From 1 April 2019 to 27 March 2020, the Advanced Virgo detector, together with the two Advanced LIGO detectors, conducted the third joint scientific observation run O3, aiming for further detections of gravitational wave signals from astrophysical sources. One of the upgrades to the Virgo detector for O3 was the implementation of the squeezed light technology to improve the detector sensitivity beyond its classical quantum shot noise limit. In this paper, we present a detailed description of the optical setup and performance of the employed squeezed light source. The squeezer was constructed as an independent, stand-alone sub-system operated in air. The generated squeezed states are tailored to exhibit high purity at intermediate squeezing levels in order to significantly reduce the interferometer shot noise level while keeping the correlated enhancement of quantum radiation pressure noise just below the actual remaining technical noise in the Advanced Virgo detector
Squeezed light at 1550 nm with a quantum noise reduction of 12.3 dB
Continuous-wave squeezed states of light at the wavelength of 1550 nm have
recently been demonstrated, but so far the obtained factors of noise
suppression still lag behind today's best squeezing values demonstrated at 1064
nm. Here we report on the realization of a half-monolithic nonlinear resonator
based on periodically-poled potassium titanyl phosphate which enabled the
direct detection of up to 12.3 dB of squeezing at 5 MHz. Squeezing was observed
down to a frequency of 2 kHz which is well within the detection band of
gravitational wave interferometers. Our results suggest that a long-term stable
1550 nm squeezed light source can be realized with strong squeezing covering
the entire detection band of a 3rd generation gravitational-wave detector such
as the Einstein Telescope
Observation of squeezed states with strong photon number oscillations
Squeezed states of light constitute an important nonclassical resource in the
field of high-precision measurements, e.g. gravitational wave detection, as
well as in the field of quantum information, e.g. for teleportation, quantum
cryptography, and distribution of entanglement in quantum computation networks.
Strong squeezing in combination with high purity, high bandwidth and high
spatial mode quality is desirable in order to achieve significantly improved
performances contrasting any classical protocols. Here we report on the
observation of the strongest squeezing to date of 11.5 dB, together with
unprecedented high state purity corresponding to a vacuum contribution of less
than 5%, and a squeezing bandwidth of about 170 MHz. The analysis of our
squeezed states reveals a significant production of higher-order pairs of
quantum-correlated photons, and the existence of strong photon number
oscillations.Comment: 7 pages, 6 figure
Squeezed light at 1064 nm and 1550 nm with a nonclassical noise suppression beyond 10 dB
[no abstract
Observation of squeezed light with 10dB quantum noise reduction
Squeezing of light's quantum noise requires temporal rearranging of photons.
This again corresponds to creation of quantum correlations between individual
photons. Squeezed light is a non-classical manifestation of light with great
potential in high-precision quantum measurements, for example in the detection
of gravitational waves. Equally promising applications have been proposed in
quantum communication. However, after 20 years of intensive research doubts
arose whether strong squeezing can ever be realized as required for eminent
applications. Here we show experimentally that strong squeezing of light's
quantum noise is possible. We reached a benchmark squeezing factor of 10 in
power (10dB). Thorough analysis reveals that even higher squeezing factors will
be feasible in our setup.Comment: 10 pages, 4 figure
Compact Multifringe Interferometry with Subpicometer Precision
Deep-frequency-modulation interferometry combines optical minimalism with multifringe readout. However, precision is key for applications such as optical gradiometers for satellite geodesy or as dimensional sensors for ground-based gravity experiments. We present a single-component interferometer smaller than a cubic inch. Two of these are compared to each other to demonstrate tilt and displacement measurements with a precision of less than 20 nrad/Hz and 1 pm/Hz at frequencies below 1 Hz
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