Tailoring the optical properties at the micro- and nanoscale is key to enable new experiments in the field of quantum optics and biophotonics. To this end, I use my strong background in numerical simulations as well as nano- and microfabrication techniques together with the expertise in spectroscopy, linear and nonlinear optics to enable and conduct experiments.
We demonstrate both experimentally and numerically a compact and efficient, optically tuneable plasmonic component utilizing a surface plasmon polariton ring resonator with nonlinearity based on trans-cis isomerization in a polymer material. We observe more than 3-fold change between high and low transmission states of the device at milliwatt control powers (~100 W/cm² by intensity), with the performance limited by switching speed of the material. Such plasmonic components can be employed in optically programmable and reconfigurable integrated photonic circuitry.
Nonlinear plasmonics at planar metal surfaces
Stefano Palomba,
Hayk Harutyunyan,
Jan Renger,
Romain Quidant,
Niek F. van Hulst,
Lukas Novotny
Philosophical Transactions of the Royal Society A
369
3497-3509
(2011)
| Journal
We investigate the nonlinear optical response of a noble metal surface. We derive the components of the third-order nonlinear susceptibility and determine an absolute value of chi^(3) ≈ 0.2 nm² V⁻², a value that is more than two orders of magnitude larger than the values found for typical nonlinear laser crystals. Using nonlinear four-wave mixing (4WM) with incident laser pulses of frequencies w1 and w2, we generate fields oscillating at the nonlinear frequency w4WM = 2w1 − w2. We identify and discuss three distinct regimes: (i) a regime where the 4WM field is propagating, (ii) a regime where it is evanescent, and (iii) a regime where the nonlinear response couples to surface plasmon polaritons.
Experimental demonstration of dielectric-loaded plasmonic waveguide disk resonators at telecom wavelengths
Sukanya Randhawa,
Alexey V. Krasavin,
Tobias Holmgaard,
Jan Renger,
Sergey I. Bozhevolnyi,
Anatoly V. Zayats,
Romain Quidant
Dielectric-loaded plasmonic waveguide disk resonators (WDRs) operating at telecom wavelengths are fabricated and investigated. Disks resonators of various radii coupled to a straight waveguide are studied both numerically and experimentally. For each disk radius, the gap between the disk and the waveguide is varied from 0 to 300 nm. Performance of the fabricated WDRs is characterized in the wavelength range of 1500–1620 nm using near-field optical microscopy. Wavelength selectivity and efficiency of the WDRs are evaluated and are in good agreement with numerical results.
While metals benefit from a strong nonlinearity at optical frequencies, its practical exploitation is limited by the weak penetration of the electric field within the metal and the screening by the surface charges. It is shown here that this limitation can be bypassed by depositing a thin dielectric layer on the metal surface or, alternatively, using a thin metal film. This strategy enables us to enhance four-wave mixing in metals by up to four orders of magnitude.
