Microscope: Scanning Probe, Scattering IR SNOM
Quick Specs
- Signal to noise ratio of 10:1 at scan times of 10-50 minutes depending on the strength of the transition dipole
- Wavelength range: 2µm - 14µm
- Spatial resolution: < 10nm
- Sensitivity: Single molecule
Environmental control:
- Controlled atmosphere in mbar to 1 atm range
- vacuum down to 10-6-10-7 mbar
- variable and low temperature: 50 K - 500 K
- Compatible with 10T magnetic fields
Scanning Probe:
- xyz sample scanning system, scan range lateral ca. 40 x 40 µm2
Laser system:
- High power Ti:S oscillator with OPO and DFG for generation of near-IR, and mid-IR continuously covering the wavelength range from ca. 2µm to 14µm with 7nm bandwidth.
- Peak power: > 1mW at mid-IR wavelengths 4µm - 9µm
- Pulse duration: 290 fs at 8µm
The scattering-type near-field optical microscope is truly a one-of-a-kind, state-of-the-art high resolution chemical imaging system developed through a partnership with Professor Markus Raschke at the University of Colorado-Boulder. It is designed to provide spectroscopic infrared vibrational near-field nanoimaging that provides ultrahigh spatial resolution down to 10 nm, vibrational spectral information in the 700 to 5000 cm-1 (14 to 2 µm) range, sensitivity down to the molecular level, and applicability under ambient and environmental conditions. This instrumentation enables temperature regulated nanospectroscopic analysis of samples within a controlled environmental chamber. The system uses a Ti-sapphire laser, an optical parametric oscillator, and difference-frequency generation optics to produce tunable infra-red light that can be focused onto a gold-coated AFM tip with a peak power of >1mW, enabling a tip enhanced field at the apex of the probe. Spatial resolution of the instrument is dictated by the geometry of the tip and has been shown to be less than 10nm. For s-SNOM imaging the AFM is operated in dynamic non-contact mode. The tip-scattered radiation is detected in the backscattering direction and the near-field signal is extracted from the far-field background by lock-in detection of the synchronized signal component with the tip dither frequency to provide contrast due to the nonlinear distance dependence of the optical tip-sample coupling. This new instrument will extend the resolution of conventional far-field IR microscopy by a factor of 1000 in spatial resolution and >100 in sensitivity.
Potential areas of application of this instrument include:
Bio-membranes, Organic Solar Cells, Heterogeneous Catalysis, Biomineralization, Contamination transport and Bioremediation, Fuel Cells and Electrochemical Interfaces, Multiferroics
For more information about this instrument and the science it will help enable, see Infrared Chemical Nano-Imaging and Spectroscopy Capability details page [.pdf, 83kb].
