The innovation engine for new materials

Anne Hébert

2013 Intern


University of California, Santa Barbara


CCS Physics

Site Abroad: 

Trinity College Dublin, Ireland


Rónán Darcy

Faculty Sponsor(s): 

John Donegan

Faculty Sponsor's Department: 


Project Title: 


Project Description: 

Conical diffraction occurs when a light beam is aligned along an optic axis of a biaxial crystal. It propagates as a skewed cone and diffracts into a hollow cylinder of light upon exiting the crystal. Equations describing the output intensity distributions have been presented by M. V. Berry for the case of a Gaussian input beam, but the theory becomes more complex for the nonGaussian cases, such as beams with Airy or Tophat intensity profiles. Such beams are difficult to produce experimentally with standard optical components, so we investigate the use of a Spatial Light Modulator (SLM) to generate such beams for conical diffraction. The recorded intensity profiles of conical diffraction with SLM generated inputs closely match the theoretical predictions. However, the hologram contains an inevitable background noise due to the pixelated nature of the SLM’s display. Since the SLM requires a linearly polarized incident beam, there is no freedom over the input polarization, which means that the output intensity profile has a crescent structure rather than a uniform ring. Despite these issues, SLMs show promise for generating beams for conical diffraction.