Construction of a laser scanning microscope for multiphoton excited optical fabrication

We present the construction and performance of a simple, programable, laser scanning nonlinear optical microscope for three-dimensional (3D) submicron fabrication. While the primary purpose of the microscope is for optical fabrication this instrument can also perform routine nonlinear optical imaging. The instrument consists of a commercial femtosecond laser system, an upright optical microscope, programable x–y scanning galvo mirrors, axial focus motor with an optical encoder, and single photon counting detection electronics. The mirror scanning and data acquisition are synchronous and are controlled by a single multipurpose I/O board and a graphical user interface written in a LabVIEW framework. The scanner is configured to scan a variety of geometrical patterns with user—controllable speeds, sizes, and aspect ratios, in either filled-in or perimeter patterns. Examples of 3D structures include channel-type structures for potential microfluidic applications and open boxes for encapsulation of cells for tissue engineering. Resolution in terms of imaging and fabrication are determined by fluorescence measurements of subresolution beads and scanning electron microscopy, respectively.