SBG Technology and the DigiLens™

SBG Labs Inc. has developed a new solid-state optical device technology, the DigiLens™ offering an alternative Illumination and Imaging method to using traditional dichroic and refractive optical solutions for many applications. The DigiLens™ relies on a fundamental Holographic optical switching technology, called the Switchable Bragg Grating (SBG).

In its simplest form, an SBG is a Bragg hologram recorded in a nanocomposite material called a Reactive Monomer Liquid Crystal Mix (RMLCM). An SBG is created by placing a cell containing the nanocomposite mixture in the interference pattern created by two intersecting beams of light. After the interference pattern is thus recorded in the mixture, it can be 'played back' by a beam that matches one of the original recording beams, recreating the other recording beam.

During recording, the nanocomposite mixture undergoes phase separation, creating regions densely populated by liquid crystal micro-droplets, interspersed by regions of clear photopolymer resulting in a grating with very high diffraction efficiency. Applying a voltage via ITO electrodes re-orientates the LC droplets, reducing the refractive index modulation. The diffraction efficiency falls to very low levels, effectively erasing the optical properties.

A DigiLens™ typically comprises several SBGs and offers all of the usual benefits of a holographic optical element with the added benefit of fast switching. As an optical module, the DigiLens™ offers the benefits of high light efficiency and ultra compact form factors resulting from the planar integration and sub millisecond switching speeds, while encoding a wide range of optical functions such as optical power, beam steering, color sequential light switching, diffusion and phase modulation.