On-Chip Optical Manipulation of Biomolecule Arrays with Nm Resolution

Abstract

Optical trapping is a powerful manipulation and measurement technique widely employed in biological and materials sciences. Miniaturizing these instruments onto optofluidic platforms holds promise for high throughput lab-on-chip applications. However, a persistent challenge with existing optofluidic devices has been controlled and precise manipulation of trapped particles. Here we report a new class of on-chip optical trapping devices. Using on-chip optical interference functionalities, an array of ultra-stable, three-dimensional optical traps is formed by the evanescent field at the anti-nodes of a standing-wave in a nanophotonic waveguide. By employing the thermo-optic effect via integrated electric microheaters, the traps can be repositioned at high speed (∼ 30 kHz) with nanometer precision. Using this device, we demonstrate trapping, sorting, and transport of particles, as well as manipulation of individual DNA molecules. Such a controllable trapping device has the potential for high-throughput precision measurements on chip.