Creating Bessel beams with a 4-f spatial filter
The Laser Teaching Center, Stony Brook University (Stony Brook, NY)
M.E. Bonomo, M.G. Cohen, & J.W. Noé
Research Experience for Undergraduate Fellowship, Summer 2012
Bessel beams are non-diffracting light beams, meaning they do not spread out as they propagate. They are characterized by their very intense, infinitely long, narrow core, which is surrounded by lesser intense concentric rings. We cannot create an ideal Bessel beam in the lab, but it is possible to make a beam that maintains a constant core size over a finite distance before exhibiting a slower rate of spreading. In fact, Bessel beam approximations have been employed in conventional barcode scanners since the early 1990’s to extend the working range of the device.
We created Bessel-like (non-diffracting) beams by a recently described 4-f spatial filtering method (Kowalczyk, Smith, and Szarmes, AJP 2009), and studied their formation and evolution with a CCD camera and ImageJ software. Observed beams maintain a core diameter under 45 microns over a distance of 47 mm.
- American Physical Society Frontiers in Optics & Laser Science XXVIII Meeting (Rochester, NY) 15 October 2012.