Diffraction-free subwavelength-beam optics
Preprint
- 17 September 2003
Abstract
Diffraction is a fundamental property of light propagation. Owing to this phenomenon,light diffracts out in all directions when it passes through a subwavelength slit.This imposes a fundamental limit on the transverse size of a light beam at a given distance from the aperture. We show that a subwavelength-sized beam propagating without diffractive broadening can be produced in free space by the constructive interference of multiple beams of a Fresnel source of the respective high-refraction-index waveguide. Moreover, it is shown that such a source can be constructed not only for continuous waves, but also for ultra-short (near single-cycle) pulses. The results theoretically demonstrate the feasibility of completely diffraction-free subwavelength-beam optics, for both continuous waves and ultra-short pulses. The approach extends operation of the near-field subwavelength-beam optics, such as near-field scanning optical microscopy and spectroscopy,to the "not-too-distant" field regime (0.5 to about 10 wavelengths).Keywords
All Related Versions
- Version 1, 2003-09-17, ArXiv
- Published version: Optics Communications, 231 (1-6), 35.
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