Since the invention and further development of lasers in the 1960s, photonics has grown
into a field that permeates virtually every aspect of modern life. As photonics deals with the …

Frequency conversion such as harmonic generation is a fundamental physical process in
nonlinear optics. The conventional nonlinear optical systems suffer from bulky size and …

Nonlinear optics is a well-established field of research that traditionally relies on the
interaction of light with macroscopic nonlinear media over distances significantly greater …

Electro-optic metasurfaces have demonstrated significant potential in enhancing the
modulation speed and efficiency for fast and large-scale free-space optical devices. Barium …

We report a strategy for preparing cost-effective plasmonic square lattices with tunable unit
structures of circles, crosses, and circle-cross pairs on a centimeter scale. The asymmetrical …

We demonstrate a nonlinear plasmonic metasurface that exhibits strongly asymmetric
second-harmonic generation: nonlinear scattering is efficient upon excitation in one …

Second-harmonic generation (SHG) is a second-order nonlinear optical process that is not
allowed in media with inversion symmetry. However, due to the broken symmetry at the …

Plasmonic nanoantennas have been extensively explored to boost nonlinear optical
processes due to their capabilities to confine optical fields on the nanoscale. In harmonic …

Coating nano/micro-structured elements with a single or multi-layered film can greatly
enhance their functionality. The experimental enhancement, however, is significantly limited …

Plasmonic metasurfaces with gradient geometry are emerging two-dimensional optical
elements with unique capabilities, such as manipulating light by imparting local, space …