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The NanoScribe GT2 Laser Lithography System is an ultramodern two-photon polymerization volumetric maskless printer. It is one of our newest acquisitions here at the Cornell NanoScale Facility (CNF). The tool was purchased in late 2019 , and delivered and installed during the second week of January 2020. This was accomplished with the help of a committee of faculty and researchers, and a grant from the NSF. The NanoScribe GT2 can create three-dimensional nanostructures using a NIR femtosecond laser via direct-write onto a photosensitive resin, which is subjected to a non-linear two-photon absorption process. This process involves cross-linking the resin via UV absorption. The laser sets a focal light cone where a concentration of the light intensity defines the exposure focal spot volume or a “3D Pixel.” Using this technique, a CAD design can be broken into an X-Y-Z coordinate system to define the structure pixel by pixel and layer by layer. The exposure side of the system sits in a fine-tuned vibration isolation table and a high-speed ultra-precise piezoelectric stage for movement in X-Y-Z , and uses a galvanic mirror defection system for focusing and beam rasterization. Models for printing can be designed using the stand-alone software DeScribe—which comes with the tool—or with any CAD software capable of outputting file formats DXF or STL. The DeScribe software can import these formats.
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Laser-based direct writing has been around for a few years especially in the semiconductor industry know as maskless lithography (MPL). Typically the two-dimensional CAD design is transferred onto the substrate that is pre-coated with a photosensitive resin via reduction laser projection. The projected pattern was reduced given the tool's numerical aperture and scan across the surface of the substrate using either a raster or vector format. These techniques are the same ones utilized in 3D direct-write. The only difference is that know you are working with a thickness degree of freedom that can be scanned across the Z-axis. The NanoScribe GT2 has a Piezo Nanopositioning stage and a high-speed galvo scanner. In the case of two-photon lithography, the light source is a pulsed femtosecond fiber laser with the center wavelength being around 780 nm.
Hardware Overview
Diagram of a simplified optical path of a Two-Photon Lithography System.
Two-photon Light Source
Hight Performance NIR femtosecond laser
Hardware Overview
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NanoScribe's Subsystems
Electronics Cabinet
Optics Cabinet [contains the laser, optics, and Galvo]
Emergency Off (EMO) switch
Printing Cabinet [Microscope, Piezo, and Stage]
Power Supply 232
System Controller
System Computer
Laser System Controller
Galvo Stage Power Supply
Monitor, Keyboard, and Mouse
Manual Microscope Controller
Joystick
Power UP and Power DOWN Procedures
Power UP Procedure
Warning!
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