ABSTRACTThe phenomenon of second harmonic generation has been studied from the earliest days of nonlinear optics.[l] To date the most impressive results in terms of conversion efficiency for as low an input power as possible have been obtained in channel waveguides made from inorganic materials.[2] However, when their second order nonlinearities (10s of pm/V) are compared with those of organic materials (10s → 100s pmn/V), it is clear that organic materials should eventually produce much better harmonic conversion efficiencies. [3]
Nonlinear Optics: Enhanced Second Harmonic Generation in Double-Resonance Colloidal Metasurfaces (Adv. Funct. Mater. 51/2018)