Grover A. Swartzlander

Optical vortex trapping of particles

Summary form only given. We demonstrate that a low-index dielectric particle can be stably trapped in three-dimensions using a stationary, focused Gaussian beam containing an optical vortex. This work is, to our knowledge, the first demonstration of three-dimensional trapping of a spherical low-index particle using a single, stationary beam. Vortex traps allow the trapping of low- and high-index particles with less risk of damage and better isolation.

Optical vortex coronagraph

We describe a method to observe dim exoplanets that eliminates light from the parent star across the entire exit pupil without sacrificing light from the planet by use of a vortex mask of topological charge m = 2.

Propagation dynamics of optical vortices

Optical vortices in linear and nonlinear media may exhibit propagation dynamics similar to hydrodynamic vortex phenomena. Analytical and numerical methods are used to describe and investigate the interaction between vortices and the background field. We demonstrate that optical vortices that have quasi-point core functions, such as optical vortex solitons, may orbit one another at rates that are orders of magnitude larger than those with nonlocalized cores.

Peering into darkness with a vortex spatial filter

I propose to use as a window the dark core of an optical vortex to examine a weak background signal hidden in the glare of a bright coherent source. Applications such as the detection of an astronomical object, forward-scattered radiation, and incoherent light are described whereby signal enhancements of at least 7 orders of magnitude may be achieved.

Holographic formation of optical-vortex filaments

An optical-vortex filament is characterized by a dark core of vanishing size and fluidlike propagation dynamics in the near-field region. This type of phase singularity does not naturally occur as an eigenmode of a cylindrically symmetric system, but it can be easily formed by computer-generated holography. The size of the core is an important attribute affecting vortex–vortex interactions within a laser beam. Here we demonstrate a means to minimize the core size, and we experimentally show that a beam-to-core size ratio exceeding 175 may be readily achieved.

Astronomical demonstration of an optical vortex coronagraph

Using an optical vortex coronagraph and simple adaptive optics techniques, we have made the first convincing demonstration of an optical vortex coronagraph that is coupled to a star gazing telescope. We suppressed by 97% the primary star of a resolvable binary system, Cor Caroli. The stars had an angular separation of 1.9λ/D at our imaging camera. The secondary star suffered no suppression from the vortex lens.

Spatial correlation vortices in partially coherent light: theory

Spatial correlation vortex dipoles may form in the four-dimensional mutual coherence function when a partially coherent light source contains an optical vortex. Analytical and numerical investigations are made in near- and far-field regimes.

Direct measurement of the transverse velocity of dark spatial solitons

We describe the direct experimental measurement of the transverse propagation velocities of dark spatial solitons. Good agreement is obtained from a comparison of the velocities measured experimentally and the velocities predicted by the two-dimensional theory of Zakharov and Shabat [Sov. Phys. JETP 37, 823 (1973)].

Optical vortex solitons and the stability of dark soliton stripes

Dark soliton stripes are robust but can decay into optical vortex solitons when subjected to a persistent, long-period, transverse modulation. We explore the nonlinear dynamics of this symmetry-breaking process and determine growth rates, vortex densities, and other characteristics by conducting a nonlinear stability analysis that uses numerical techniques for several cases of special interest.

The optical vortex coronagraph

An optical vortex coronagraph is a high contrast imaging system which has the potential to completely extinguish light from an on-axis point source, allowing glare-free, high throughput imaging of off-axis targets. An important application is the direct detection of exoplanets orbiting distant stars. The optical physics of the OVC is reviewed, a heuristic argument describing its operation is presented for the first time, and performance limitations are explored.