11 research outputs found
Coherent anti-Stokes Raman scattering microscopy for quantitative characterization of mixing and flow in microfluidics
Get PDFWe present an optical, noninvasive and label-free approach to characterize flow profiles in microfluidic devices. Coherent anti-Stokes Raman scattering signals were used to map the mass transport in a microfluidic device that was then related back to the local flow rate of dilute solutes having constant fluid properties. Flow characterization was demonstrated in two common types of microfluidic devices, polydimethylsiloxane/glass square channels and wet-etched glass tapered channels
Optical trapping for the manipulation of colloidal particles
No full textThe simultaneous positioning of multiple colloidal particles using optical tweezers is described here. It is illustrated that novel structures of very specific design can be constructed on a microscopic scale (see Figure) and that the structure can be locked in by photopolymerization of the surrounding solvent. Such artificially created surfaces may find applications as lithographic masks or diffraction gratings
Creation of Tailored Surfaces by Optical Manipulation of Colloidal Particles
No full textNo abstract available
Tailored surfaces using optically manipulated colloidal particles
No full textOptical trapping techniques have been used extensively to manipulate biological objects and micrometer-sized colloids in a wide variety of investigations. We have used an extension of this technique, scanning laser optical trapping, to simultaneously trap multiple colloids in a designed pattern and have locked-in this artificially created structure through photopolymerization of the monomer-containing solvent. This technique can be used as a means of constructing templates for lithography or as a starting point for creation of larger three-dimensional colloidal structures
Design of a scanning laser optical trap for multiparticle manipulation
No full textIn recent years, single-beam optical traps have been used to manipulate individual colloids and biological objects such as cells. We have implemented a rapidly scanning laser optical trap with rates as high as 1200 Hz where a single laser beam is used to trap multiple colloids simultaneously. The optics are optimized to achieve a small laser focus size and a large scanning pattern in the sample. This approach provides great pattern flexibility and, because of the use of piezoelectrics, small particles (1 μm in diameter) in low-viscosity solvents, such as water, can be readily manipulated
