arXiv subjects

Mikhail Korobko

Publications and source records attributed to Mikhail Korobko.

23 records · Page 2Linked to original sources

arXiv2019

Quantum expander for gravitational-wave observatories

Quantum uncertainty of laser light limits the sensitivity of gravitational-wave observatories. In the past 30 years, techniques for squeezing the quantum uncertainty as well as for enhancing the gravitational-wave signal with optical resonators were invented. Resonators, however, have finite linewidths; and the high signal frequencies that are produced during the scientifically highly interesting ring-down of astrophysical compact-binary mergers cannot be resolved today. Here, we propose an optical approach for expanding the detection bandwidth. It uses quantum uncertainty squeezing inside one of the optical resonators, compensating for finite resonators' linewidths while maintaining the low-frequency sensitivity unchanged. Introducing the quantum expander for boosting the sensitivity of future gravitational-wave detectors, we envision it to become a new tool in other cavity-enhanced metrological experiments.

quant-ph↗

arXiv2018

Mitigating mode-matching loss in nonclassical laser interferometry

Strongly squeezed states of light are a key technology in boosting the sensitivity of interferometric setups, such as in gravitational-wave detectors. However, the practical use of squeezed states is limited by optical loss, which reduces the observable squeeze factor. Here we experimentally demonstrate that introducing squeezed states in additional, higher-order spatial modes can significantly improve the observed nonclassical sensitivity improvement when the loss is due to mode-matching deficiencies. Our results could be directly applied to gravitational-wave detectors, where this type of loss is a major contribution.

quant-ph↗

arXiv2017

Engineering the Optical Spring via Intra-Cavity Optical-Parametric Amplification

The 'optical spring' results from dynamical back-action and can be used to improve the sensitivity of cavity-enhanced gravitational-wave detectors. The effect occurs if an oscillation of the cavity length results in an oscillation of the intra-cavity light power having such a phase relation that the light's radiation pressure force amplifies the oscillation of the cavity length. Here, we analyse a Michelson interferometer whose optical-spring cavity includes an additional optical-parametric amplifier with adjustable phase. We find that the phase of the parametric pump field is a versatile parameter for shaping the interferometer's spectral density.

quant-ph↗

arXiv2017

Beating the standard sensitivity-bandwidth limit of cavity-enhanced interferometers with internal squeezed-light generation

The shot-noise limited peak sensitivity of cavity-enhanced interferometric measurement devices, such as gravitational-wave detectors, can be improved by increasing the cavity finesse, even when comparing fixed intra-cavity light powers. For a fixed light power inside the detector, this comes at the price of a proportional reduction in the detection bandwidth. High sensitivity over a large span of signal frequencies, however, is essential for astronomical observations. It is possible to overcome this standard sensitivity-bandwidth limit using non-classical correlations in the light field. Here, we investigate the internal squeezing approach, where the parametric amplification process creates a non-classical correlation directly inside the interferometer cavity. We analyse the limits of the approach theoretically, and measure 36% increase in the sensitivity-bandwidth product compared to the classical case. To our knowledge this is the first experimental demonstration of an improvement in the sensitivity-bandwidth product using internal squeezing, opening the way for a new class of optomechanical force sensing devices.

quant-ph↗

arXiv2014

Paired carriers as a way to reduce quantum noise of multi-carrier gravitational-wave detectors

We explore new regimes of laser interferometric gravitational-wave detectors with multiple optical carriers which allow to reduce the quantum noise of these detectors. In particular, we show that using two carriers with the opposite detunings, homodyne angles, and squeezing angles, but identical other parameters (the antisymmetric carriers), one can suppress the quantum noise in such a way that its spectrum follows the Standard Quantum Limit (SQL) at low frequencies. Relaxing this antisymmetry condition, it is also possible to slightly overcome the SQL in broadband. Combining several such pairs in the xylophone configuration, it is possible to shape the quantum noise spectrum flexibly.

gr-qc↗