Toward the optical “magic carpet”: reducing the divergence of a light sheet below the diffraction limit

Abstract

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.

LITE microscopy: Tilted light-sheet excitation of model organisms offers high resolution and low photobleaching

“…We used LITE microscopy to produce a sheet of light with constant thickness over the desired objective’s field of view (FOV; 150 µm). We theorized we could accomplish this thin illumination scheme using established cylindrical, lens-based cosine wave optics ( Golub et al, 2015 ). We therefore calculated the theoretical side view of the light sheet to visualize the predicted sheet width and length (width = 4.3 µm, length = 270 µm; Fig.…”

Light-sheet microscopy: a tutorial

“…Other alternatives to generate LSs with cylindrical optics have been reported. These are based on the use of: (i) Powell lenses to transform the Gaussian into top-hat beams, increasing in this way the resolution while avoiding sidelobes [143]; (ii) rectangular slits to produce non-diffracting carpets of light, having reduced sidelobes [144]; and (iii) a tilted cylindrical lens to produce 1D Airy beams [145].…”

LITE microscopy: a technique for high numerical aperture, low photobleaching fluorescence imaging

“…In equation (3), L' is the elongated sheet length, and R1 is the radius of the inner photomask slits 7 . In order to put equation (3) in terms of w, we equated R1 to NAeff using equation (1) and substituted the equivalence into the equation (3) denominator to arrive at equation (4):…”

“…of the total laser energy should in the center sheet 7 . Side lobe minimization is important to reduce the probability of excitation and emission outside the detection objective focal plane.…”

“…S1). The theoretical and practical design of these slits were first described and implemented by Golub et al in 2015. Briefly, this method increased L of a cylindrical lens-based light sheet beyond what equation (2) predicts by creating an Fadero et al, 2017 8 interference pattern at the cylindrical lens focal plane between two harmonic cosine waves 7 . Golub et al (2015) presented the equation for the depth of field of the elongated light sheet below in equation (3):…”