Novel Device Adds to Interferometry’s Optical Capabilities

An advance in interferometry, named the Hilbert-space analyzer, may lead to novel ways of analyzing beams of light that are not dependent on temporal delays.

Interferometers make minute measurements by manipulating beams of light using an optical delay — an effect that's typically achieved by adding length to one of the beam's paths, which slows the signal down. The creators of the Hilbert-space analyzer have found a way to introduce a delay that is unrelated to time.

The device, which was developed by research teams from the University of Central Florida and the University of Rochester, operates as a kind of generalized beamsplitter by introducing a "generalized delay" that avoids adding extra lengths in the beam paths. Instead, it manipulates the beam and transforms it using spatial light modulators.

The research applies quantum mechanics formalism to the field of classical optics and "provides an optical device that has been missing from the arsenal of optics," said associate professor Ayman F. Abouraddy.

Generalized optical interferometry using a Hilbert-space analyzer. A beam is directed to an interferometer and is split between two paths, the lower of which contains a generalized delay (α) replacing the usual temporal delay. Then the two beams are recombined to produce an interferogram. Courtesy of Ayman F. Abouraddy.

The Hilbert-space analyzer can use a traditional delay to obtain the wavelengths from which the signal is constructed via optical interferometry. It can use a generalized delay to extract the contributions of other waveforms, or modal sets, to an optical beam.

"We don’t need to find new approaches for new modal sets: the Hilbert-space analyzer is a one-stop shop for all your modal analysis needs," Abouraddy said.

“For now, the most interesting application for Hilbert-space analyzers is in optical communications, which uses light to carry information across some distance,” he added.

The presentation, “Hilbert-Space Analyzers: Basis-Neutral Modal Analysis via Generalized Optical Interferometry,” by Ayman Abouraddy, will take place at Frontiers in Optics (FiO) / Laser Science (LS) from 2:00 to 2:30 p.m., Friday, October 21, 2016, in the Highland Room C, Radisson Hotel Rochester Riverside, Rochester, N.Y.