[OpenSPIM] A new type of sharper beam?

[Feinstein, Timothy N]

Hi folks,

The following paper struck me as potentially very useful.  It seems that a simple(ish) array of slits in front of the cylinder lens can create a narrow, subdiffraction-sized sheet of light via interference which propagates without broadening.  Kind of a 2D Bessel beam.
"Toward the optical "magic carpet": reducing the divergence of a light sheet below the diffraction limit
In 3D, diffraction-free or Bessel beams are well known and have found applications in diverse fields. An analog in 2D, or pseudonondiffracting (PND) beams, is a nontrivial problem, and existing methods suffer from deficiencies. For example, Airy beams are not highly localized, some PND beams have significant side lobes, and a cosine beam has to be truncated by a very narrow aperture thus discarding most of the energy. We show, both theoretically and experimentally, that it is possible to generate a quasi-nondiffracting 2D light beam in a simple and efficient fashion. This is achieved by placing a mask consisting of a pair of double slits on a cylindrical lens. The applications include light sheet microscopy/optical sectioning and particle manipulation."

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-40-21-5121

That sounds like a subdiffraction-width plane that almost anyone could make.  That is interesting to me as the extra complexity and cost of Bessel beams have led me to put off exploring more precise illumination methods for now.  As far as I can tell you just need to fabricate a sufficiently precise mask, and you might need a different mask for each wavelength.  What do you think?

Best,


Tim

Timothy Feinstein, Ph.D.
Research Scientist
University of Pittsburgh Department of Developmental Biology
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