APPLICATIONS OF TECHNOLOGY:
- Scan-probe microscopy
- Optical microscopy
- Probe tip manufacturing
- Enables collection of physical, chemical and morphological information
- High spatial resolution (~ 20 nm) optical imaging and spectroscopy
- Nearly background-free imaging
- Eliminates special sample and substrate handling requirements
- Operates over a wide range of optical frequencies (broadband)
A team of Berkeley Lab researchers has developed a nano-optical device that provides details of chemical, physical, and morphological properties on the nanoscale, in real time, and at high resolution (approximately 20 nm). Replacing an atomic force microscopy (AFM) tip with the Berkeley Lab device provides the spatial data available with the AFM tip along with optical data from which scientists can identify chemical composition and details about the sample’s electronic structure. This unprecedented level of detail in materials research can lead to development of more efficient, cost-effective solar cells, battery electrodes, digital storage media and polymers, among other discoveries.
The device, a tapered, four-sided tip fabricated on the end of an optical fiber, acts as a transducer of far-field to near-field light. The taper enables the tip to channel light of all wavelengths into an enhanced field at the tip. The size of the gap between two sides of the device at its tip determines the resolution. The device’s resemblance to a bell tower, specifically the well-known structure on the UC Berkeley campus, led researchers to name it the “campanile tip.”
The campanile tip delivers optimal near-field properties including highly efficient far-field to near-field coupling, ultra large-field enhancement and sensitivity, nanoscale resolution, and almost background-free imaging – all over a wide range of wavelengths. In addition, it removes sample and substrate requirements by effectively integrating into the campanile design all of the nano-optical components responsible for coupling, concentrating, and enhancing local fields. This makes the Berkeley Lab technology easy to use and accessible to all researchers.
Electron and scan/probe microscopes offer the ability to characterize materials at a high, sub-atomic spatial resolution, but do not offer information about the sample’s composition or chemistry at the molecular level. For chemical information, optical or vibrational spectroscopy is used. However, the diffraction limit, i.e., the inability to focus light to a spot smaller than approximately half its wavelength, presents limitations in sensitivity, bandwidth, and resolution as well as particular sample requirements. The campanile tip overcomes the major limitations restricting spectroscopy measurements at the nanoscale by combining the advantages of a scan / probe microscope with those of optical spectroscopy.
DEVELOPMENT STAGE: Bench scale prototype designed to investigate solar-to-electric energy conversion.
STATUS: Patent pending. Available for licensing or collaborative research.
FOR MORE INFORMATION:
Bao, W., Melli, M., Caselli, N., Riboli, F., Wiersma, D. S., Staffaroni, M., Choo, H., Ogletree, D. F., Aloni, S., Bokor, J., Cabrini, S., Intonti, F., Salmeron, M. B., Yablonovitch, E., Schuck, P. J., Weber-Bargioni, A., “Mapping Local Charge Recombination Heterogeneity by Multidimensional Nanospectroscopic Imaging,” Science, Vol 338, December 7, 2012.
Hatt, Alison. “Seeing in Color at the Nanoscale,” Berkeley Lab News Center, December 6, 2012.
REFERENCE NUMBER: IB-3314