Nano Lett. 16, 7191–7197 (2016)

Credit: AMERICAN CHEMICAL SOCIETY

Nanoantennas made from nanodisks of the semiconductor AlGaAs are capable of efficient second-harmonic generation and also controlling the directionality and polarization of the emission, say researchers from Australia, Italy and China. Such nanoscale sources of light could prove useful for applications in nonlinear imaging, biomaging and hologram generation. The study was performed by a team from the Australian National University, the University of Brescia and Nankai University. The researchers fabricated nanodisk antennas with diameters 300–700 nm and studied the efficiency of the second-harmonic generation at 778 nm in the forward and backward directions when pumped with infrared light at 1,556 nm. Nonlinear conversion efficiencies exceeding 10−4 were measured and it was also shown that the nanoantennas are capable of generating complex vector beams with radial polarization.