All Done with Mirrors: Smart Substrates for 3D Views Dr. J. Alexander Liddle Dr. Matthew McMahon, Dr. Andrew Berglund, Dr. Peter Carmichael, Dr. Jabez McClelland

Benefits/Advantages Microfabricated substrates can be combined with most other optical microscopy techniques –Simple –Easy to make –Add lots of information Function: Resolve ambiguity –Same positions when viewed from above, but different heights Application: Put cell inside sample well –Rapid screening of cell height –Modest-resolution, high-throughput 3D information

What Motivated the Research? Cui, Björk, Liddle, Sönnichsen, Boussert & Alivisatos Nano Lett. 2004, 1093 Solution-Based Nanoparticle Assembly

3D Imaging in Optical Microscope Goal: Monitor/Measure Dynamics by Seeing in 3D –Track assembling particles in as close to real-time as possible The smaller they are, the faster they move How?

2D Track from 2D Images 2D tracks easily constructed from 2D video –Special software needed to get accurate particle positions Some codes available free

The ideal would be… Oh well…hmmm….

Orthogonal Tracking Microscopy Reduce the problem of tracking in 3D to the problem of tracking in 2D twice MICROFABRICATED SAMPLE CHAMBER WITH INTEGRATED REFLECTIVE OPTICS Si

Software Enhances Technology New algorithms developed that are fast and can handle complicated shapes Easy Difficult

Demonstration All-silicon substrate Squares defined by photolithography Anisotropic etch of Si by KOH: 54.7° sidewalls Pyramidal indentations Movie: 190 nm fluorescent polystyrene sphere in water

Future Development Hardware: –Integrate more complex optical elements Better mirrors (i.e. gold) Filters Polarizers Diffractive elements Software –Explore asymmetry Asymmetric objects: rotational motion Asymmetric radiation patterns

Summary Microfabricated substrates can be combined with most other optical microscopy techniques Resolve ambiguity –Same positions when viewed from above but different heights Put cell inside sample well –Rapid screening of cell height –Modest-resolution, high-throughput 3D information A patent application covering the concept of using microfabricated optics to permit imaging in 3D is pending.