Tight focusing of plane waves from micro-fabricated spherical mirrors.
We derive a formula for the light field of a monochromatic plane wave that is truncated and reflected by a spherical mirror. Within the scalar field approximation, our formula is valid even for deep mirrors, where the aperture radius approaches the radius of curvature. We apply this result to micro-fabricated mirrors whose size scales are in the range of tens to hundreds of wavelengths, and show that sub-wavelength focusing (full-width at half-maximum intensity) can be achieved. This opens up the possibility of scalable arrays of tightly focused optical dipole traps without the need for high-performance optical systems.
Goldwin
J
J
Department of Physics, Division of Quantum Optics and Laser Science, Imperial College, London, United Kingdom. j.goldwin@imperial.ac.uk
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