# Synopsis: A New Window on Nanometer Apertures

Experiment and theory combine to give a more complete picture of a fundamental problem in diffraction optics.

Several precision optical techniques, such as high-resolution near-field scanning microscopy, depend on nanometer-sized holes to guide electromagnetic waves. Scientists have studied diffraction through subwavelength apertures since the $17$th century, yet despite extensive effort, theory has not entirely accounted for the electromagnetic behavior of holes in real metals with finite thicknesses and dielectric constants. In a paper in Physical Review Letters, Juemin Yi, at the University of Strasbourg, France, and colleagues wrap up the problem in a complete package of theory and experiment.

Apertures large compared to the wavelength of electromagnetic waves yield their secrets to a rather straightforward theoretical approach, but when the holes become close to or smaller than the wavelength, the calculations become trickier. Moreover, experimental study is complicated by actual physical implementations involving real materials with a finite thickness rather than infinitely thin metal plates. Yi et al. conducted experiments in which they measured the full diffraction patterns of a circular aperture all the way from large holes down to subwavelength openings in realistic structures.

To accurately understand their observations, the authors find that not only do collective electron oscillations—the surface plasmons—need to be dealt with, but the interaction of the plasmons with waveguide modes of the aperture have to be included. Yi et al. derive a set of simple expressions that make it more straightforward to estimate the total transmission of light through a hole from measurements made along a single direction, as opposed to having to integrate over a wide range of angles. – David Voss

More Features »

### Announcements

More Announcements »

Nanophysics

## Next Synopsis

Atomic and Molecular Physics

## Related Articles

Atomic and Molecular Physics

### Synopsis: A Sextet of Entangled Laser Modes

Researchers have entangled six modes of a laser cavity—a record number for such a device. Read More »

Optics

### Synopsis: Counting Photons from a Polariton Condensate

By counting the photons emitted from a microcavity, researchers shed light on the nature of an exotic condensate of quasiparticles contained in the cavity.     Read More »

Graphene

### Synopsis: How Defects Alter Graphene Nanoribbons

Molecular defects can improve the mechanical flexibility of graphene nanoribbons without affecting their electrical properties, new experiments show. Read More »