Integrated Optical Waveguide Trapping and Quantitative Phase Microscopy

This work introduces a fully integrated platform combining planar optical waveguide-based trapping (WT) with quantitative phase microscopy (QPM) to investigate the biomechanical response of red blood cells (RBCs) under controlled optical forces. A key feature of this system is the use of waveguide chips fabricated on opaque silicon substrates, which enable planar optical trapping and propulsion of biological cells through evanescent field interactions. These waveguides generate high-intensity, highly confined optical forces, on the order of piconewtons, that are ideal for manipulating delicate biological specimens without damage. To facilitate label-free, quantitative imaging of cells during waveguide-based manipulation, a compact reflection-mode Linnik interferometer was developed and integrated with the trapping system. This setup captures off-axis interferograms that allow rapid, single-shot phase reconstruction using Fourier transform methods. The integrated WT-QPM system allows real-time measurement of morphological changes in RBCs during planar trapping. 

References:

1. Ahmad, Azeem, Vishesh Dubey, Vijay Raj Singh, et al. "Quantitative phase microscopy of red blood cells during planar trapping and propulsion." Lab on a Chip 18, no. 19 (2018): 3025-3036. Link