Microfluidic chip having on-chip electrically tunable high-throughput nanophotonic trap

A microfluidic device based on optical trapping of particles, comprising:

• a substrate structured to include a fluidic region which can contain a fluid having particles;
• optical waveguides formed on the substrate to include (1) a first Mach-Zehnder interferometer that is located outside the fluidic region and receives an input laser beam and splits the received input laser beam into two laser beams along two different optical paths of the first Mach-Zehnder interferometer to produce a first optical beam;
• and (2) second Mach-Zehnder interferometers that are located inside the fluidic region and each receive a respective portion of light of the first optical beam output by the first Mach-Zehnder interferometer, wherein each second Mach-Zehnder Interferometer splits received light into two optical paths that are connected so that each optical path receives counter-propagating optical beams in opposite directions that interact with each other to form standing optical waves to optically trap particles;
• a first electrically controllable phase control device formed on the substrate and coupled to a location of the first Mach-Zehnder interferometer and operable to control an optical delay between the two optical paths of the first Mach-Zehnder interferometer;
• and
• second electrically controllable phase control devices formed on the substrate and coupled to the second Mach-Zehnder interferometers, respectively, each second electrically controllable phase control device operable to control an optical delay between the two optical paths of a respective second Mach-Zehnder interferometer.

A method for manipulating particles in a fluid based on optical trapping via evanescent fields of standing optical waves in optical waveguides, comprising:

• supplying a fluid having particles in a fluidic region on a substrate in which different optical waveguide sections are located to be in contact with the fluid;
• splitting an input optical beam into different optical beams into the different optical waveguide sections in such a way that each of the different optical waveguide sections has two counter-propagating optical beams that prorogate in opposite directions and interact with each other to form a standing optical wave to optically trap particles at or near a surface of each optical waveguide section;
• and
• controlling an amount of the optical phase delay of light at one or more locations on the substrate to cause a shift in locations of nodes of an optical standing wave in at least one optical waveguide section to change trapping locations of the trapped particles at the optical waveguide section.