Jeff Z. Salvail

Full characterization of polarization states of light via direct measurement

Researchers report the first direct measurements of the wavefunction and Dirac distributions for polarization states of light. Their implementation determines the general description of the pure state of a qubit. This technique is simple, fast and general, and has an advantage over the conventional approach of performing quantum state tomography.

Experimental realization of optical eigenmode super-resolution.

We experimentally demonstrate the feasibility of a super-resolution technique based on eigenmode decomposition. This technique has been proposed theoretically but, to the best of our knowledge, has not previously been realized experimentally for optical imaging systems with circular apertures. We use a standard diffraction-limited 4f imaging system with circular apertures for which the radial eigenmodes are the circular prolate spheroidal functions. For three original objects with different content of angular information we achieve 45%, 49%, and 89% improvement of resolution over the Rayleigh limit. The work presented can be considered as progress towards the goal of reaching the quantum limits of super-resolution.

Generation of Orbital Angular Momentum Bell States and their Verification via Accessible Nonlinear Witnesses

We produce all four Bell states in the orbital angular momentum degree of freedom and use a new class of accessible nonlinear entanglement witnesses to verify their entanglement.

Development of a slow-light spectrometer on a chip

We discuss the design and development of a slow-light spectrometer on a chip with the particular example of an arrayed waveguide grating based spectrometer. We investigate designs for slow-light elements based on photonic crystal waveguides and grating structures. The designs will be fabricated using electron-beam lithography and UV photolithography on a silicon-on-insulator platform. We optimize the geometry of these structures by numerical simulations to achieve a uniform and large group index over the largest possible wavelength range.

Nonlinear Optics: The Enabling Technology for Quantum Information Science

Nonlinear optical processes such as parametric down conversion and squeezed light generation are key elements of most quantum protocols, leading to crucial applications such as quantum imaging, sub-shot-noise metrology, and secure communication.

Eigenmode super-resolution imaging in arbitrary optical systems

We investigate optical super-resolution by means of eigenmode decomposition in arbitrary imaging systems. This technique is applicable for arbitrary objects but requires a knowledge of the eigenmodes of the imaging system. We outline a reconstruction technique that can be applied even to systems in which the eigenmodes are not orthogonal, and we present numerical simulations of eigenmode super-resolution in systems with resolution limited both by diffraction and by aberrations. Our results indicate that optical super-resolution by direct eigenmode decomposition provides a versatile method of sub-diffraction and distortion-free imaging in arbitrary optical systems.