Optimal phase measurements with bright- and vacuum-seeded SU(1,1) interferometers

Abstract

The SU(1,1) interferometer can be thought of as a Mach-Zehnder interferometer with its linear beamsplitters replaced with parametric nonlinear optical processes. We consider the cases of bright and vacuum-seeded SU(1,1) interferometers using intensity or homodyne detectors. A simplified, truncated scheme with only one nonlinear interaction is introduced, which not only beats conventional intensity detection with a bright seed, but can saturate the phase sensitivity bound set by the quantum Fisher information. We also show that the truncated scheme achieves a sub-shot-noise phase sensitivity in the vacuum-seeded case, despite the phase-sensing optical beams having no well-defined phase.

Optimum quantum resource distribution for phase measurement and quantum information tapping in a dual-beam SU(1,1) interferometer

“…Recently, a new type of quantum interferometer known as SU(1,1) interferometer was demonstrated to exhibit sensitivity enhancement in phase measurement [8][9][10][11][12][13][14][15] and in the meantime possesses detection loss tolerance property [11,13,15], which is a huge advantage over the squeezed state schemes. Although the hardware of the new interferometer changes from beam splitters to parametric amplifiers, the underlining physics is still quantum noise reduction by noise cancelation through quantum entanglement [14,[16][17][18], similar to Ref.…”

“…Quantum entanglement, as a quantum resource, can also be applied to enhance phase measurement sensitivity by quantum noise cancelation via quantum correlation [6,7].Recently, a new type of quantum interferometer known as SU(1,1) interferometer was demonstrated to exhibit sensitivity enhancement in phase measurement [8][9][10][11][12][13][14][15] and in the meantime possesses detection loss tolerance property [11,13,15], which is a huge advantage over the squeezed state schemes. Although the hardware of the new interferometer changes from beam splitters to parametric amplifiers, the underlining physics is still quantum noise reduction by noise cancelation through quantum entanglement [14,[16][17][18], similar to Ref.[6].However, it was shown [18] that these quantum entanglement-based schemes can only gives the information splitting of phase signal encoded on entangled fields with high transfer coefficients of 0.72 ± 0.06 and 0.69 ± 0.06, respectively, satisfying the condition for quantum optical tapping.Compared to previous methods, dual-beam sensing SUI not only makes full use of the quantum resource for phase measurement, but also is insensitive to propagation and de-9 tection losses and thus lifts the barrier for the quantum enhanced metrology and quantum communication in practical applications. The loss tolerance property shows that dual-beam sensing SUI has great potentials in those situations when quantum efficiency of detection system limits the implementation of quantum enhanced measurement, such as those working at wavelength that lacks efficient photo-detectors (for example, wavelength longer than 2 µm or ultra violet region).Although the dual-beam sensing scheme has twice the SNR as the single-beam sensing scheme, its implementation requires the two correlated beams to be nearly the same so as to probe the same phase change.…”

Effect of imperfect homodyne visibility on multi-spatial-mode two-mode squeezing measurements

“…The methodology used to implement our model is described in detail by Anderson et al [18]. We find analytical expressions for the quadrature noises of the probe and the conjugate beams as well as the noises of the joint quadratures using the non-commuting algebra package in Ref.…”

Reframing SU(1,1) Interferometry

“…Over the last decade, a number of experimental groups have implemented SU(1,1) interferometry in a variety of forms [33][34][35][36][37][38][39][40][41][42][43][44]. A brief review of SU(1,1) interferometry within the context of other contemporary uses of squeezed light, which touches on some of questions considered in this paper, can be found in [45].…”