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Seminar presented by the Stanford Optical Society
Dr. James Schuck
Lawrence Berkeley National Laboratory
Thursday, Oct. 28th, 4:15 PM, Hewlett 102. Refreshments at 4:00
High spatial resolution optical investigations of nanostructures and nanomaterials
In this talk, I will begin by introducing the Molecular Foundry, a National Nanoscience
Research Center, and discuss the optics-related capabilities and research currently taking place
there. I will then describe some of my group’s recent work, in which we demonstrate the nonperturbative use of diffraction-limited nonlinear optics and photon localization microscopy to
visualize the nanometer-scale controlled shifts of ultraconfined zeptoliter mode volumes within
plasmonic nanostructures. Unlike tip-based or coating-based methods, these measurements do not
affect the electromagnetic properties of the nanostructure being investigated. The photon-limited
localization accuracy of nanoscale mode distributions is determined for many of the measured
devices to be within a 95% confidence interval of +/- 2.5 nm. In addition, because of the accuracy
of these photon localization microscopy measurements, we were able to observe and characterize
the effects of nm-scale fabrication variations and irregularities on local plasmonic mode
distributions.
As a proof of concept, we image the local energy-dependent changes in near-field
distributions within individual gold asymmetric bowtie nano-colorsorters (ABnCs) [1], a class of
plasmonic color sorters, based on the “cross” nanoantenna geometry. These devices are
specifically engineered to not only capture and confine optical fields, but also to spectrally filter
and steer them while maintaining nanoscale field distributions. Their spectral properties and
localized spatial mode distributions can be readily tuned by controlled asymmetry, and each of
the zeptoliter mode volumes within an ABnC, separated by only tens of nm, can be individually
addressed simply by adjusting the incident wavelength. We imaged relative spatial shifts down to
7 nm of distinct modes within the same device, demonstrating the local field manipulation
capabilities of ABnCs, in strong agreement with theoretical calculations.
Finally, I will finish with a brief discussion of our efforts in developing novel near-field
optical probes and their use in hyperspectral nano-imaging.
Jim Schuck is currently a Staff Scientist at the Molecular Foundry located at
Lawrence Berkeley National Laboratories. He earned his B.A. in Physics at
UC Berkeley, and his Ph.D. in Applied Physics with Prof. Robert Grober at Y
ale University. After obtaining his Ph.D., he then spent three years as a postd
octoral researcher at Stanford University, where he was advised by Prof. W.
E.
Moerner
studying
optical
nanoantennas
and
singlemolecule spectroscopy. His research currently focuses on nanophotonic/plasmonic device applications and nanoscale optical imaging spectr
oscopy of novel materials.