Tuesday, December 4, 2012
12:00 pm
Annenberg 105

IST Lunch Bunch

3D Nanofocusing
Hyuck Choo, Assistant Professor, Electrical Engineering, Caltech

The development of techniques for confining photons efficiently on the deep sub-wavelength spatial scale will revolutionize scientific research and engineering practices.  Nanofocusing processes are essential for maximizing the performance of a new class of nanoscale optical/photonic devices as well as sub-diffraction-resolution imaging modules for medical and fundamental scientific research.  However, the efficient coupling of light into extremely small nanofocusing devices has posed a major challenge, especially in on-chip nanophotonics, due to the need to overcome various loss mechanisms as well as the nanofabrication challenges.

In this presentation, I will discuss the achievement of highly efficient nanofocusing in an Au-SiO2-Au gap plasmon waveguide using a carefully engineered 3D taper.  The dimensions of the SiO2 layer, perpendicular to the direction of wave propagation, tapered linearly below 100 nm.  Our simulations suggested that the 3D linear-tapering approach could focus 830 nm light into a 2-by-5 nm2 area with ≤3 dB loss and an intensity enhancement of 3.0 × 104.  In a two-photon luminescence measurement, our device achieved an intensity enhancement of 400 within a 14-by-80 nm2 area and transmittance of 74%. 

 

Contact Sydney Garstang sydney@caltech.edu at 626-395-4555
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