Since its discovery in the 1960s, nonlinear optics has revolutionized optical technologies and laser industry. Development of efficient nanoscale nonlinear sources will pave the way for new applications in photonic circuitry, quantum optics and bio-sensing. However, nonlinear signal generation at dimensions smaller than the wavelength of light brings new challenges. These include the reduced light-matter interaction volume, mode overlap and increased losses. Here, we develop hybrid plasmonic – dielectric metamaterials that overcome these limitations and show a dramatic increase of the efficiency of nonlinear optical response at the nanoscale.
In the first part of my talk I will introduce a new type of 3-dimensional, non-planar plasmonic metasurface and demonstrate 4 orders of magnitude enhancement of second harmonic generation (SHG) compared to doubly-resonant plasmonic systems. The geometry of the metamaterial design minimizes the destructive interference of nonlinear emission into the far-field, provides independently tunable resonances both for fundamental and harmonic frequencies, a good mutual overlap of the modes and a strong interaction with the nonlinear material. In the second part of my talk I will describe our recent efforts to combine localized plasmon modes with propagating photonic waveguide modes. The hybridized mode that is formed as a result of such coupling can exhibit the desirable features of plasmonic modes such as high Purcell factors and large field enhancement but with significantly reduced losses.
Our findings can enable the development of efficient nanoscale single photon sources, integrated frequency converters and other nonlinear devices.