Quantum Optical Technologies for Metrology, Sensing, and Imaging

Abstract

Abstract-Over the past 20 years, bright sources of entangled photons have led to a renaissance in quantum optical interferometry. Optical interferometry has been used to test the foundations of quantum mechanics and implement some of the novel ideas associated with quantum entanglement such as quantum teleportation, quantum cryptography, quantum lithography, quantum computing logic gates, and quantum metrology. In this paper, we focus on the new ways that have been developed to exploit quantum optical entanglement in quantum metrology to beat the shot-noise limit, which can be used, e.g., in fiber optical gyroscopes and in sensors for biological or chemical targets. We also discuss how this entanglement can be used to beat the Rayleigh diffraction limit in imaging systems such as in LIDAR and optical lithography.

Fundamental precision limit of a Mach-Zehnder interferometric sensor when one of the inputs is the vacuum

“…In the latter scenario, we provide an explicit measurement strategy that beats the SNL. We also point out that these two scenarios are physically different and correspond to different types of sensing applications.Introduction.-In the field of quantum metrology [1][2][3], a Mach-Zehnder interferometer (MZI) is a tried and true workhorse that has the additional advantage that any result obtained for it also applies to a Michelson interferometer (MI) and hence has a potential application to gravitational wave detection. In most current implementations of gravitational wave detectors, the MI is fed with a strong coherent state of light in one input port and vacuum in the other (Fig.…”

Roadmap on optical sensors

“…In general, laser light is approximated by a coherent state. Therefore, the precision of a measurement based upon the coherent state of light is ultimately limited by shot noise [37], which is proportional to $1/\sqrt{I}$ or $1/\sqrt{N}$ where I and N denote the intensity and average number of photons of the light, respectively. If I or N is sufficiently high, which is the case in most laser-based optical sensing, the actual precision of the measurement is not limited by shot noise but by some other uncertainties that may occur during the sensing process.…”

Fisher information of a squeezed-state interferometer with a finite photon-number resolution

“…Quantum-enhanced optical phase estimation through the Mach-Zehnder interferometer (MZI) is important for multiple areas of scientific research [1][2][3][4][5][6][7], such as imaging, sensing, and high-precision gravitational waves detection. The MZIbased optical phase estimation consists of three steps (see e.g.…”

“…Using a coherentstate of light as the input, the achievable phase sensitivity per measurement is limited by the classical (or shot noise) limit δϕ ≡ √ v∆ϕ ∼ 1/ √n , as the QFI F Q ∼ O(n). To improve the precision beyond the classical limit (∼ 1/ √n ), it is necessary to employ quantum resources, such as entanglement and squeezing in the input state [1][2][3][4][5][6][7]. In this * Electronic address: wenyang@csrc.ac.cn † Electronic address: grjin@bjtu.edu.cn ‡ Electronic address: cpsun@csrc.ac.cn context, the squeezed states of light play an important role and have been widely studied in the past decades ever since the pioneer work of Caves in 1981 [1], who shows that by feeding a coherent state |α into one port of the MZI and a squeezed vacuum |ξ into the other port, the unknown phase shift can be estimated with a precision beyond the classical limit.…”