Details

Autor(en) / Beteiligte

• Ren, Ming-Liang
• Liu, Wenjing
• Aspetti, Carlos O.
• Sun, Liaoxin
• Agarwal, Ritesh

Titel

Enhanced second-harmonic generation from metal-integrated semiconductor nanowires via highly confined whispering gallery modes

Ist Teil von

• Nature communications, 2014-11, Vol.5 (1), p.5432-5432, Article 5432

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2014

Quelle

MEDLINE

Beschreibungen/Notizen

• Coherent and tunable nanoscale light sources utilizing optical nonlinearities are required for applications ranging from imaging and bio-sensing to on-chip all-optical signal processing. However, owing to their small sizes, the efficiency of nanostructures even with high nonlinear coefficients is poor, therefore requiring very high excitation energies. Although surface-plasmon resonances of metal nanostructures can enhance surface nonlinear processes such as second-harmonic generation, they still suffer from low conversion efficiencies owing to their intrinsically low nonlinear coefficients. Here we show highly enhanced and directional second-harmonic generation from individual CdS nanowires integrated with silver nanocavities (>1,000 times higher external efficiency compared with bare CdS), in which the lowest-order whispering gallery mode is engineered to concentrate light in the nonlinear material while minimizing Ohmic losses. The directional nonlinear signal is redirected into another waveguide, which is then utilized to configure an optical router that can potentially serve as a tunable coherent light source to enable on-chip signal processing for integrated nanophotonic systems. Nanoscale light sources using nonlinearities are needed in many applications but their small size leads to very low efficiencies. Here, Ren et al. exploit the highly confined whispering gallery modes in metal-coated nanowires to achieve enhanced second-harmonic generation with minimal Ohmic losses.