The Optical Characterization Laboratory is located in 354 Davey and is home to many photonics systems dedicated to the synthesis or optical characterization of Nanoscale materials.
UV Laser Materials Processing Workstation
This workstation includes a Coherent Ar+ 351-nm continuous wave laser source, which is used to record information in UV sensitive polymers. This source is coupled to an optical set-up designed for creating 1-, 2-, and 3-D interference patterns with periods of less than 0.5 µm. It is currently being used to pattern a variety of materials including commercially available photoresists and polymer dispersed liquid crystals.
Near-field Scanning Optical Microscope (NSOM)
The Omicron GMBG Near-Field Optical Microscope (NSOM) with Atomic Force attachment is capable of optical and topographical measurements. It can measure optical fields with a 100 nm resolution, which is well under the diffraction limit of the conventional counterparts. During the acquisition process the NSOM measures the topography of the area of interest as well. The resolution in this mode is few nm in lateral and sub-nanometer in vertical direction.
We have designated space in the MRSEC CFL for an Acton Research TriplePro triple spectrometer and a Princeton Instruments Spec-10:100BR detector. The TriplePro spectrograph will be coupled to the existing CLF Pulsed Spectra-Physics Nd:YAG 250 Series laser. This Nd:YAG laser is combined with an Optical Parametric Oscillator (OPO) tunable from 450 nm up to 1.8 µm. The energy per pulse in this range is in the order of few tens of mJ, and the YAG laser itself can be used as a powerful (hundreds of mJ) laser source for each of its lines. When completed this instrumentation will provide excellent light throughput and laser-light rejection as well as the low noise, high NIR quantum efficiency, and spatial resolution needed for biomaterials and metalloprotein research.
Nanomechanical Characterization System
Used to study the mechanical properties of nanoscale PZT cantilevers. The system consists of a small ion-pumped vacuum chamber with controlled leak back that is mounted onto the stage of a Nikon inverted microscope in the MRSEC CFL. This will allow chips with many cantilevers to be studied under ambient pressures ranging from atmospheric to 10-9 torr. Long working distance microscope objectives are used to focus a laser beam onto the oscillator through a viewport. Interference between light reflected from the moving oscillator and the underlying substrate is sensed by an ac-coupled photodetector whose output is fed to a spectrum analyzer for analysis.
Fluorescence Optical Microscope and Optical Tweezers
Two Nikon TE2000 optical microscopes are currently in use by MRSEC members for materials characterization and dynamic motors experiments. Both are configured with fluorescence and differential interference contrast capabilities and connected to CCD cameras and monitors. One microscope, housed in Hallowell building, is used extensively for biological motor experiments and is being outfitted with an optical tweezer for measuring and manipulating motor proteins and nanoparticles. The second microscope is housed in the MRSEC CFL and is used primarily for micro-fluidic measurements, but is also configured for biological studies.