Holographic 3D tracking of microscopic tools

We originally proposed and experimentally demonstrated the targeted-light delivery capability of so-called Wave-guided Optical Waveguides (WOWs) three years ago. As these WOWs are maneuvered in 3D space, it is important to maintain efficient light coupling through their integrated waveguide structures.

In this work we demonstrate the use of real-time diffractive techniques to create focal spots that can dynamically track and couple to the WOWs during operation in a volume. This is done by using a phase-only spatial light modulator to encode the needed diffractive phase patterns to generate a plurality of dynamic coupling spots.

In addition, we include our proprietary GPC Light Shaper before the diffractive setup to efficiently illuminate the rectangular shaped spatial light modulator by a Gaussian laser beam. The method is initially tested for a single WOW and we have experimentally demonstrated dynamic tracking and coupling for both lateral and axial displacements of the WOWs.

The ability to switch from on-demand to continuous addressing with efficient illumination leverages our WOWs for potential applications in near-field stimulation and nonlinear optics at small scales.