Our research group studies polymer structure and dynamics using optical techniques. Various optical microscopes and lasers are used in the experiments.
Scanning Near-Field Optical Microscope (SNOM)
Four machines are available to obtain various kinds of information: time-resolved, spectroscopic, and polarization dependent measurements. Several laser sources can be used to excite chemicals over a broad wavelength range including the deep UV region.
Near-Field Optical Microscopy.
Super-resolution and Conventional Fluorescence Microscopes
The spatial resolution of conventional optical microscopy is limited to a few hundred nanometers due to the diffraction limit of light; therefore, it has not been applicable to the observation of nanometric structure. However, with super-resolution techniques, the image analysis with the novel optical detection scheme enables us to obtain the structural information at a single nanometer scale. In our laboratory, several super-resolution and conventional microscopes are used to observe single chains of polymeric materials.
Microscope with total internal reflection illumination.
The illumination with evanescent field generated by the total internal reflection enables selective imaging at the surface.
Electron-multiplying CCD (EMCCD) Camera.
High sensitivity of them allows the detection of a single molecule.
Pulse lasers are employed to observe the time-resolved fluorescence spectrum and to perform multi-photon excitation under a microscope. Ti:sapphire, N2-dye, and pulsed diode lasers are available.
Pico-sec and femto-sec lasers for time-resolved fluorescence and multi-photon excitation, respectively.
N2-Dye Laser (left) and Nano-sec OPO Laser (right).
The dye laser provides 1-ns pulses at an energy of 20-200 uJ in the wavelength range of 400-900 nm. The OPO laser emits 5-ns pulses at an energy of 1-4 mW in the wavelength range of 420-2000 nm. They are used as light sources for photo-acoustic measurements.
This laser emits a broad band pulse at a wavelength range of 500 - 1600 nm with an energy of ca. 3 uJ.
Time Correlated Single Photon Counting System
Atomic Force Microscope
Dynamic Light Scattering System