Author: Chih-Kang Shih
Requested Type: Pre-Selected Invited
Submitted: 2015-03-13 21:13:37
Co-authors: S. Gwo
The University of Texas, Physics Department
Austin, Texas 78712
Plasmonic nannolaser is an active “photonic” device with physical size much smaller than the wavelength. Realization of such plasmonic nanolasers can solve the size-mismatch problem between active electronics at nanometer scale and the conventional photonics at micron scale. In the development of metal-based nanophotonics the most critical challenge is to overcome the inherent loss for surface plasmon polaritons (SPP). We have overcome this adverse effect by developing epitaxial silver films on semiconductor (EpSoS) as the plasmonic platform. By using this EpSoS platform, we demonstrate the first CW operation of plasmonic nanolaser with ultra-low thresholds and with deep sub-diffraction physical dimensions. In addition to demonstrating common lasing characteristics, we reveal the temporal coherence by using second order photon-photon correlation measurements. We further show that all color (red, green and blue) nanolasing can be achieved on the same EpSoS platform without the need to control the cavity length. This is explained by a novel “autotuning” mechanism which is a unique feature for plasmonic nanolasers. Finally, we show that in the blue nanolaser, the threshold is undetectably small (<10 W/cm^2), approaching the so-called threshold-less regime.
*This work was carried out in collaboration with Professor S. Gwo of National Tsing-Hua University.