Optics Letters

Phase-shift-amplified interferometry

Moshe Ben Ayun, Egor Liokumovitch, Daniel Gotliv, Shmuel Sternklar

Published May 11, 2018• 11 citations

Abstract

We present a new technique for improving the sensitivity of an interferometer, phase-shift-amplified interferometry (PAI), which is based on two embedded interferometers. The internal interferometer, which is biased in anti-phase, amplifies the phase shift; the external interferometer converts this into an amplified intensity shift. PAI can improve the sensitivity of standard interferometers by an order of magnitude or more. The theory of PAI, including its enhanced immunity to relative intensity noise, phase noise, and other post-detection noise and distortion components, is presented. We experimentally demonstrate a phase-shift amplification factor of 11.

DOI: 10.1364/ol.43.002402

Related papers

Heterodyne phase-shift-amplified interferometry with improved shot-noise-limited sensitivity and immunity to RIN

Egor Liokumovitch, Shmuel Sternklar

Phase-shift-amplified interferometry (PAI) is demonstrated using a heterodyne detection scheme. We demonstrate a sensitivity amplification factor of 35, giving 7.9 ⋅ 10 − 4 rad, or 40 pm displacement, resolution. This was achieved due to the improved immunity of PAI to the total relative intensity noise (RIN) of the system. In addition, we predict a factor of 2 fundamental improvement to shot-noise-limited phase-shift sensitivity as compared to a regular heterodyne Mach–Zehnder interferometer.

Optics LettersFeb 20, 20201 citation

Heterodyne phase-shift-amplified interferometry with improved shot-noise-limited sensitivity

Egor Liokumovitch, Shmuel Sternklar

Heterodyne phase-shift-amplified interferometry is demonstrated. A phase-shift-amplification factor of 30 is achieved. Theory predicts a shot-noise-limited sensitivity improvement of 2 compared to a standard heterodyne Mach-Zehnder interferometer.

Frontiers in OpticsJan 1, 20190 citations

Coherent Amplifier-Empowered Quantum Interferometer: Preserving Sensitivity and Quantum Advantage under High Loss

Jie Zhao, Zeliang Wu, Haoran Liu +6 more

Quantum interferometers offer phase measurement capabilities that surpass the standard quantum limit (SQL), with phase sensitivity and quantum enhancement factor serving as key performance metrics. However, practical implementations face severe degradation of both metrics due to unavoidable losses, representing the foremost challenge in advancing quantum interferometry toward real-world applications. To address this challenge, we propose a coherent-amplifier-empowered quantum interferometer. The coherent amplifier dramatically suppresses the decay of both sensitivity and quantum enhancement under high-loss conditions, maintaining phase sensitivity beyond the original SQL even for losses exceeding 90%. Using an injected 4.2 dB squeezed-vacuum state in experimental demonstration, our scheme reduces the quantum enhancement degradation under 90% loss from 3.7 dB in a conventional quantum interferometer (CQI) to only 1.5 dB. More importantly, the phase sensitivity degradation under the same loss is limited to 4.0 dB, markedly outperforming the 11.2 dB degradation observed in a CQI. This improvement is enabled by the coherent amplifier's phase-sensitive photon amplification and its protection of the quantum state. This breakthrough in amplifier-empowered quantum interferometry overcomes the critical barrier to practical deployment, enabling robust quantum-enhanced measurements in lossy environments.

quant-pharXiv:2601.17876Jan 27, 20260 citations

Efficient phase-sensitive compensation in lossy interferometry using optical amplification

Tingting Jiang, Jie Zhao, Feiyu Yao +5 more

Optical interferometers, as precision measurement tools, inevitably experience optical path losses in practical applications, which introduce unavoidable vacuum noise and reduce the sensitivity in the phase estimation. To mitigate the effects of losses on sensitivity, we propose an enhanced interferometer scheme that integrates a Raman amplifier. This amplifier is strategically positioned within the lossy interference arm to counteract the reduction in phase sensitivity caused by losses. Our research highlights the crucial role of amplifier positioning, revealing that pre-amplification (PRA, placing the amplifier before the lossy section) significantly outperforms post-amplification (POA, placing the amplifier after the lossy section). PRA effectively enhances sensitivity by increasing the number of phase-sensitive particles and minimizing noise amplification. As the loss increases, the superiority of PRA in mitigating loss effects becomes increasingly evident. To validate our approach, we conducted experimental demonstrations. When the losses reach 90%, PRA experimentally achieves a sensitivity improvement of 4.6 dB compared with the case of only loss without the amplifier, equivalent to increasing the input laser power by over 8 times. PRA can effectively improve the robustness against losses for the practical application solely through the use of a coherent amplifier, with a simple technical implementation yet remarkable enhancement effects. We believe that current PRA-enhanced interferometry facilitates the practical implementation of phase measurement in environments characterized by significant loss.

Optics ExpressApr 2, 20252 citations

Phase amplification in optical interferometry with weak measurement

Li Li, Yuan Li, You-Lang Zhang +5 more

Improving the phase resolution of interferometry is crucial for high-precision measurements of various physical quantities. Systematic phase errors dominate the phase uncertainties in most realistic optical interferometers. Here, we propose and experimentally demonstrate a weak measurement scheme to considerably suppress the phase uncertainties by the direct amplification of the phase shift in optical interferometry. Given an initial ultrasmall phase shift between orthogonal polarization states, we observe a phase amplification effect with a factor of 388. Our weak measurement scheme provides a practical approach to significantly improve the interferometric phase resolution, which is favorable for precision measurement applications.

arXiv:1803.07735Physical Review AMar 29, 201834 citations

Enhancement of the phase-measurement sensitivity beyond the standard quantum limit by a nonlinear interferometer

Z. Y. Ou

A nonlinear interferometer uses nonlinear elements as beam splitters to split and to recombine optical waves for interference. As a result, the interference fringe size has a nonlinear dependence on the intensity of the field for phase sensing and leads to an enhanced phase signal. In this paper, a practical scheme of nonlinear interferometry for precision phase measurement is analyzed with parametric amplifiers as the nonlinear beam splitters. It is found that the signal due to phase shift is enhanced by a factor of the amplification gain as compared to a linear interferometer with the same phase-sensing light intensity while the quantum noise is kept at the vacuum level, thus, effectively increasing the signal-to-noise ratio (SNR) beyond the standard quantum limit. Furthermore, the scheme is not as sensitive to the detection loss as the linear scheme with a squeezed state for noise reduction. However, losses inside the interferometer limit the enhancement factor in SNR. We apply the concept to a Michelson interferometer but with parametric amplifiers involved for gravitational-wave detection. We find that effective power is increased by the gain of the amplifiers without actually increasing the cycling power inside the interferometer. Furthermore, the full benefits with squeezed input and variational output or the combination of a quantum nondemolition interferometer for sensitivity beyond the standard quantum limit apply here with even better results. Such a nonlinear interferometer will find wide applications in precision measurements.

Physical Review AFeb 14, 2012195 citations