Tuning the mapping of second-harmonic generation in silver nanoshells
School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, P.R. China
2 Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi’an Jiaotong University, Xi’an 710049, P.R. China
Revised: 5 July 2011
Accepted: 16 August 2011
Published online: 28 September 2011
The distribution patterns of the second-harmonic generation (SHG) enhancement factor in the incident plane of silver nanoshell at resonance frequencies have been studied by using electrostatic approximation. The mapping feature of SHG corresponding to double frequency local field enhancement is different from that of fundamental case. At longer wavelength (SHG enhancement resulting from local field at double frequency), large SHG enhancements are only observed outside the shell. However, hot spots also take place inside the silver shell at shorter wavelength (SHG enhancement resulting from local field at fundamental frequency). The effect of outer surrounding media on the SHG corresponding to local field at fundamental frequency is also very different from that of double frequency. It has been found that the azimuth angle dependent SHG at shorter wavelength split into two maximums when the surrounding dielectric constant is increased, which is absent for SHG at longer wavelength.
© EDP Sciences, 2011