Three-dimensionally crossing manifold micro-mixer for fast mixing in a short channel length.

In this study, we report a neo-conceptive three-dimensionally (3D) crossing manifold micromixer (CMM) embedded in microchannel. Fabricated by sequential processes of photolithography and two photon absorption stereolithography, this leads to a microfluidic system with a built-in micromixer in a site controlled manner. The effectiveness of CMM is investigated numerically and experimentally. Through the numerical simulation, it is estimated that a high mixing ratio of 90% can be obtained even in a channel length shorter than five times the channel width. This compares well with the conventional passive type of micromixers that have a gradual increase in mixing efficiency with the length of the channel. Furthermore, the mixing performance of the realized CMM built-in microchannel is observed by confocal microscopy.

Proportional enlargement of movement by using an optically driven multi-link system with an elastic joint.

Diverse movements using optical manipulation have been introduced. These are generally performed in the focal region of the laser beam. To achieve a wider range of movements based on precise motion transformation, an effective method for optical manipulation that overcomes the important obstacles such as small optical trapping forces, friction, and the viscosity of fluids is required. A multi-link system with an elastic joint is introduced that provides precise motion transformation and amplification. By considering the physical properties of the structure and the optical trapping force, an elastic micron-scale joint with the simple shape of a thin plate was designed. As a further example of a multi-link system with an elastic joint, a double 4-link system for motion enlargement was designed and fabricated. By performing experimental evaluations of the fabricated structures, it was confirmed that multi-link systems with an elastic joint were effective tools for precise motion transformation through optical manipulation.

Fabrication of three-dimensional SiC ceramic microstructures with near-zero shrinkage via dual crosslinking induced stereolithography.

Three-dimensional SiC ceramic microstructures with near-zero shrinkage were fabricated from a simple inorganic polymer mixture by inducing dual photocuring routes to produce highly dense polymer features by stereolithography and subsequent pyrolysis at 600 degrees C.

Fabrication of nano- and micro-scale UV imprint stamp using diamond-like carbon coating technology.

Two-dimensional (2-D) and three-dimensional (3-D) diamond-like carbon (DLC) stamps for ultraviolet nanoimprint lithography were fabricated with two methods: namely, a DLC coating process, followed by focused ion beam lithography; and two-photon polymerization patterning, followed by nanoscale-thick DLC coating. We used focused ion beam lithography to fabricate 70 nm deep lines with a width of 100 nm, as well as 70 nm deep lines with a width of 150 nm, on 100 nm thick DLC layers coated on quartz substrates. We also used two-photon polymerization patterning and a DLC coating process to successfully fabricate 200 nm wide lines, as well as 3-D rings with a diameter of 1.35 microm and a height of 1.97 microm, and a 3-D cone with a bottom diameter of 2.88 microm and a height of 1.97 microm. The wafers were successfully printed on an UV-NIL using the DLC stamps without an anti-adhesive layer. The correlation between the dimensions of the stamp's features and the corresponding imprinted features was excellent.