Supersensitive measurement of angular displacements using entangled photons

Abstract

We show that the use of path-entangled states of photons, having nonzero orbital angular momentum (OAM), increases the resolution and sensitivity of angular-displacement measurements performed using an interferometer. In the ideal case of maximally path-entangled states, the resolution of angular-displacement measurements increases by a factor of Nl, while the uncertainty in the measurement of angular displacements scales as 1/N l, where N is the number of entangled photons, half of which carry, on average, an OAM of +lh per photon and the other half carry an OAM of −lh per photon. We analyze measurement schemes for two-and four-photon entangled states produced by parametric down-conversion and, by employing a 4×4 matrix formalism to study the propagation of entangled OAM modes, obtain explicit expressions for the resolution and sensitivity in these schemes. These results constitute an improvement over what could be obtained with N nonentangled photons carrying an orbital angular momentum of |l|h per photon. −l ). Using Eqs. (25)-(27), we solve Eq. (30) to obtain the following operator relations:

Quantum orbital angular momentum of elliptically symmetric light

“…Since the seminal paper by Allen et al [1] research in this field has accelerated. Interest has been driven by the promise of access to higher dimensional Hilbert spaces (especially larger alphabet quantum key distribution [2,3]), potential probes of heretofore hidden phenomena (even astronomical events [4]), metrology [5], use in micro-mechanics [6], and perhaps most importantlythe insight the study of OAM yields into the fundamental properties of light fields themselves. Especially illuminating, is the investigation of the quantum aspects of OAM carrying light modes.…”

Nanosecond-pulse-controlled higher-order sideband comb in a GaAs optomechanical disk resonator in the non-perturbative regime

“…For laser pulses with multicycle, the influence of the CEP becomes smaller, and it seems hardly to have the CEP effects. In fact, it is still a great challenge to measure and control the CEP of laser pulses with tens of optical cycles [40,47]. Here we give a full description of non-perturbative signals and CEP effects in the optomechanical system, and show how to control the optomechanical system by using the power and CEP of the driven pulse.…”

“…On the other hand, developments of ultrafast optics show that light-matter interaction in the few-cycle regime is very sensitive to the carrier-envelope phase (CEP) of laser field [36]. Therefore, few-cycle light pulses make significant impact on optics and atomic physics [37][38][39][40]. For atoms or molecules which are exposed to a few-cycle laser pulse, the HHG spectrum will also depend on the CEP [41], and there is a periodicity upon the CEP [31].…”

Single-shot measurement of the orbital-angular-momentum spectrum of light

“…This is in contrast to the polarization degree of freedom, which provides a discrete but only a two-dimensional basis [2][3][4] . High-dimensional quantum information protocols have many distinct advantages in terms of security [16][17][18] , transmission bandwidth 19,20 , gate implementations 21,22 , supersensitive measurements 23 , and fundamental tests of quantum mechanics [24][25][26][27] . In the classical domain, the high-dimensional OAM-states can increase the system capacities and spectral efficiencies [9][10][11] .…”