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.

Multiphoton microfabrication enables the production of three-dimensional microstructures with sub-100 nm resolution via direct laser writing using a femtosecond, pulsed laser beam. The range of materials available for multiphoton processing has increased steadily over the past decade, and the extent of potential applications has increased correspondingly. Current application areas include photonics, microelectromechanical systems, and microelectronics. We review the fundamentals of multiphoton microfabrication and recent progress on materials and applications. Approaches for the mass production of threedimensional structures created with multiphoton fabrication are also discussed.An optical micrograph of a metallized inductor created with multiphoton polymerization.

An optically driven lobed micropump was developed using three-dimensional two-photon microfabrication. The two built-in rotors, 9 m 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 0.2-0.7 m / 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.