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Nanfang Yu and colleagues show that plasmonics can be used to reduce the spread of laser beams. They demonstrate their technique using a quantum cascade laser, and show that by defining a metallic subwavelength slit and grating onto the facet of the laser, a beam divergence of 2.4 degrees can be achieved. The technique can potentially be used to collimate the beams from a variety of different lasers.
Light is often thought of in terms of radial polarization, but longitudinal polarization is also possible, and it has some intriguing possibilities for particle acceleration. Binary optics, combined with a high-numerical-aperture lens, is a potential route to achieving light with this unusual property.
A stack of silver nanorods could, according to calculations, be the answer to performing subwavelength colour imaging over far-field distances. The metallic nanolens is designed to operate in the visible wavelength range and by tapering the nanorods, image magnification is also shown to be feasible. If realized such a lens could be useful for imaging applications in the biomedical sciences and other fields.
Incoherent optical spatial solitons are self-trapped beams with a multimodal structure that varies randomly in time. All incoherent solitons observed so far have been supported by nonlinearities with slow response times. Here, Segev and colleagues demonstrate such solitons in nonlinear media with fast (essentially instantaneous) response times and show that new physical features appear.
Optical tweezers are well known for being able to control and move microscopic objects with high precision using focused laser beams. Alexander Grigorenko and colleagues report three-dimensional tweezers based on coupled pairs of gold nanodots in standard tweezer set-ups, which offer improved trapping efficiencies and reduced trapping volumes. Their tweezers could pave the way to improved manipulation of fragile, tiny biological objects.
Demonstration of an imaging system that can capture high-resolution 3D fluorescent images of biological speciments without the need for any moving parts.