Multi-path interferometry using single photons

Coherent perfect absorption of path entangled single photons.

We examine the question of coherent perfect absorption (CPA) of single photons, and more generally, of the quantum fields by a macroscopic medium. We show the CPA of path entangled single photons in a Fabry-Perot interferometer containing an absorptive medium. The frequency of perfect absorption can be controlled by changing the interferometer parameters like the reflectivity and the complex di...

Operational path-phase complementarity in single-photon interferometry

We examine two setups that reveal different operational implications of path-phase complementarity for single photons in a Mach-Zehnder interferometer (MZI). In both setups, the which-way (WW) information is recorded in the polarization state of the photon serving as a “flying which-way detector”. In the “predictive” variant, using a fixed initial state, one obtains duality relation between the...

Interferometry Using a Multi-Photon Tunneling Coupler

Interferometers involving special quantum states can show fascinating and counter-intuitive effects. Recent discussion of photon DeBroglie waves has provided a particularly interesting perspective [1, 2]: the basic idea is that whenever photons display correlated dynamics as they pass through a nonlinear interferometer, a description in terms of multi-photon bound particles can be useful. Multi...

Subnanometer Displacement Measurement Using Common-path Grating Interferometry

Single and Entangled Photons

Quantum computing is a sought after technology that will greatly increase the speed and security of computations and communications. The understanding of quantum computing and information technology is dependent upon the understanding of quantum interactions. The difference between current computers and quantum computers lies in the fundamental units of information utilized. The qubit, which is...