170 research outputs found
Principles of calculating the dynamical response of misaligned complex resonant optical interferometers
In the long-baseline laser interferometers for measuring gravitational waves that are now under construction, understanding the dynamical response to small distortions such as angular alignment fluctuations presents a unique challenge. These interferometers comprise multiple coupled optical resonators with light storage times approaching 100 m. We present a basic formalism to calculate the frequency dependence of periodic variations in angular alignment and longitudinal displacement of the resonator mirrors. The electromagnetic field is decomposed into a superposition of higher-order spatial modes, Fourier frequency components, and polarization states. Alignment fluctuations and length variations of free-space propagation are represented by matrix operators that act on the multicomponent state vectors of the field
Quantum noise in gravitational-wave interferometers: Overview and recent developments
We present an overview of quantum noise in gravitational wave
interferometers. Gravitational wave detectors are extensively modified variants
of a Michelson interferometer and the quantum noise couplings are strongly
influenced by the interferometer configuration. We describe recent developments
in the treatment of quantum noise in the complex interferometer configurations
of present-day and future gravitational-wave detectors. In addition, we explore
prospects for the use of squeezed light in future interferometers, including
consideration of the effects of losses, and the choice of optimal readout
schemes.Comment: 13 pages, 5 figure
Mathematical framework for simulation of quantum fields in complex interferometers using the two-photon formalism
We present a mathematical framework for simulation of optical fields in
complex gravitational-wave interferometers. The simulation framework uses the
two-photon formalism for optical fields and includes radiation pressure
effects, an important addition required for simulating signal and noise fields
in next-generation interferometers with high circulating power. We present a
comparison of results from the simulation with analytical calculation and show
that accurate agreement is achieved
Experimental test of an alignment-sensing scheme for a gravitational-wave interferometer
An alignment-sensing scheme for all significant angular degrees of freedom of a power-recycled Michelson interferometer with Fabry Perot cavities in the arms was tested on a tabletop interferometer. The response to misalignment of all degrees of freedom was measured at each sensor, and good agreement was found between measured and theoretical values
Frequency-Dependent Squeeze Amplitude Attenuation and Squeeze Angle Rotation by Electromagnetically Induced Transparency for Gravitational Wave Interferometers
We study the effects of frequency-dependent squeeze amplitude attenuation and
squeeze angle rotation by electromagnetically induced transparency (EIT) on
gravitational wave (GW) interferometers. We propose the use of low-pass,
band-pass, and high-pass EIT filters, an S-shaped EIT filter, and an
intra-cavity EIT filter to generate frequency-dependent squeezing for injection
into the antisymmetric port of GW interferometers. We find that the EIT filters
have several advantages over the previous filter designs with regard to optical
losses, compactness, and the tunability of the filter linewidth.Comment: 4 page
Gravitationally induced phase shift on a single photon
The effect of the Earth's gravitational potential on a quantum wave function
has only been observed for massive particles. In this paper we present a scheme
to measure a gravitationally induced phase shift on a single photon travelling
in a coherent superposition along different paths of an optical fiber
interferometer. To create a measurable signal for the interaction between the
static gravitational potential and the wave function of the photon, we propose
a variant of a conventional Mach-Zehnder interferometer. We show that the
predicted relative phase difference of radians is measurable even in
the presence of fiber noise, provided additional stabilization techniques are
implemented for each arm of a large-scale fiber interferometer. Effects arising
from the rotation of the Earth and the material properties of the fibers are
analysed. We conclude that optical fiber interferometry is a feasible way to
measure the gravitationally induced phase shift on a single-photon wave
function, and thus provides a means to corroborate the equivalence of the
energy of the photon and its effective gravitational mass.Comment: 13 pages, 5 figure
A route to observing ponderomotive entanglement with optically trapped mirrors
The radiation pressure of two detuned laser beams can create a stable trap
for a suspended cavity mirror; here it is shown that such a configuration
entangles the output light fields via interaction with the mirror.
Intra-cavity, the opto-mechanical system can become entangled also. The degree
of entanglement is quantified spectrally using the logarithmic negativity.
Entanglement survives in the experimentally accessible regime of gram-scale
masses subject to thermal noise at room temperature.Comment: 4 pages, 4 figure
Generation of a stable low-frequency squeezed vacuum field with periodically-poled KTiOPO at 1064 nm
We report on the generation of a stable continuous-wave low-frequency
squeezed vacuum field with a squeezing level of dB at 1064 nm, the
wavelength at which laser interferometers for gravitational wave (GW) detection
operate, using periodically poled KTiOPO (PPKTP) in a sub-threshold optical
parametric oscillator. PPKTP has the advantages of higher nonlinearity, smaller
intra-crystal and pump-induced seed absorption, user-specified parametric
down-conversion temperature, wider temperature tuning range, and lower
susceptibility to thermal lensing over alternative nonlinear materials such as
MgO doped or periodically poled LiNbO, and is, therefore, an excellent
material for generation of squeezed vacuum fields for application to laser
interferometers for GW detection
Non-invasive Measurements of Cavity Parameters by Use of Squeezed Vacuum
We propose and experimentally demonstrate a method for non-invasive
measurements of cavity parameters by injection of squeezed vacuum into an
optical cavity. The principle behind this technique is the destruction of the
correlation between upper and lower quantum sidebands with respect to the
carrier frequency when the squeezed field is incident on the cavity. This
method is especially useful for ultrahigh cavities, such as whispering
gallery mode (WGM) cavities, in which absorption and scattering by
light-induced nonlinear processes inhibit precise measurements of the cavity
parameters. We show that the linewidth of a test cavity is measured to be
kHz, which agrees with the classically measured linewidth
of the cavity within the uncertainty ( kHz).Comment: 6 pages, 4 figure
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