We propose a method for three-dimensional microfabrication with photopolymerization stimulated by two-photon absorption with a pulsed infrared laser. An experimental system for the microfabrication has been developed with a Ti:sapphire laser whose oscillating wavelength and pulse width are 790 nm and 200 fs, respectively. The usefulness of the proposed method has been verified by fabrication of several kinds of microstructure by use of a resin consisting of photoinitiators, urethane acrylate monomers, and urethane acrylate oligomers.

An optically driven lobed micropump was developed using three-dimensional two-photon microfabrication. The two built-in rotors, 9μm in diameter, are cooperatively driven by means of time-divided scanning of a single laser beam. It was demonstrated that a tracer particle was moved by simultaneously rotating the two rotors. The velocity of the tracer particle was proportional to the rotation speed of the rotors in the range of 0.2–0.7μm∕s. The flow rate was estimated to be sub-pL/min level. This ultralow flow rate will be useful for further integration and miniaturization of micro-total-analysis systems.

Optically driven micromanipulators with submicron probe tips are proposed and developed by using two-photon microstereolithography. The micromanipulators are worked by maneuvering their movable component with a focused laser beam, and an actual pair of microtweezers was opened and shut precisely. We also propose an effective method of controlling movable micromachines with great freedom of movement. In this method, a dot is attached to a movable component for trapping and driving it by a single laser beam. A microneedle was induced to perform several types of motion such as rotation and translation. The optically driven micromanipulators are useful for bionanotechnology applications that require work to be done in aqueous solutions.

We developed a promising method to fabricate three-dimensional microstructures by using single-photon-absorbed polymerization confined to the vicinity of a tightly focused spot. This localized polymerization is based on the nonlinear response of the photopolymerizable resin to optical intensity with sufficiently low exposure. The nonlinear response was verified by measuring polymerization exotherm at different light intensities. The proposed method enables us to make even movable microstructures without any of the supporting parts or sacrificial layers normally required with conventional micromachining. In the experiment reported here, we fabricated a microgear with an external diameter of 47 μm and an attached shaft.