Optical separation of heterogeneous size distributions of microparticles on silicon nitride strip waveguides

Abstract

We demonstrate two complementary optical separation techniques of dielectric particles on the surface of silicon nitride waveguides. Glass particles ranging from 2 μm to 10 μm in diameter are separated at guided powers below 40 mW. The effects of optical, viscous, and frictional forces on the particles are modeled and experimentally shown to enable separation. Particle interactions are investigated and shown to decrease measured particle velocity without interfering with the overall particle separation distribution. The demonstrated separation techniques have the potential to be integrated with microfluidic structures for cell sorting.

Nanophotonic trapping: precise manipulation and measurement of biomolecular arrays

“…In that size regime, both the gradient and scattering optical forces are greater for larger particles, supporting the possibility of using such a system for sorting cells or biofunctionalized microparticles. In related work, Khan et al used Si 3 N 4 waveguides to sort a heterogeneous mixture of glass microparticles, achieving successful fractionation despite directly observed particle collisions on the waveguide . In the most advanced analytical application demonstrated so far with a simple waveguide propulsion design, initially reported by Schein et al, the size and surface interactions of nanoparticles trapped on a waveguide were precisely characterized by monitoring scattered light .…”

“…In related work, Khan et al used Si 3 N 4 waveguides to sort a heterogeneous mixture of glass microparticles, achieving successful fractionation despite directly observed particle collisions on the waveguide. 41 In the most advanced analytical application demonstrated so far with a simple waveguide propulsion design, initially reported by Schein et al, the size and surface interactions of nanoparticles trapped on a waveguide were precisely characterized by monitoring scattered light. 42,43 These waveguide propulsion demonstrations show that the manipulation technique is versatile with respect to the waveguiding material and the size and composition of transported targets and that they are compatible with microfluidic delivery systems that will be needed for biological studies in end-user devices.…”

Low-Temperature and Low-Pressure Silicon Nitride Deposition by ECR-PECVD for Optical Waveguides

“…As thin-film silicon nitride (Si 3 N 4 ) becomes a standard material in integrated photonics, the need for a broad range of deposition recipes for different applications becomes apparent. Si 3 N 4 has many demonstrations as a low-loss waveguide material [1][2][3][4][5][6] for diverse applications due to its transparency in the visible and near-infrared (NIR), such as biological sensing and particle manipulation, environmental monitoring, optical interconnects and anti-reflective (AR) coatings [7][8][9][10][11][12]. Due to the need for Si 3 N 4 integration with metal components or organic materials for many of these uses, it is advantageous to have flexible fabrication techniques that operate at lower deposition temperatures and pressures.…”

On-chip phase measurement for microparticles trapped on a waveguide

“…[1][2][3][4][5][6][7][8][9][10][11][12] Optical waveguides have an evanescent field that stretches about 250 nm from their surfaces. They are thus attractive devices for on-chip manipulation, detection and sorting of particles.…”

“…When a particle solution is introduced on a waveguide surface, the particles interact with this field. 11 The trapped particles are normally observed from above, using bright-field, dark-field or fluorescence microscopy. This was first demonstrated in 1992 by Kawata and Sugiura.…”