The dependence of resonance frequency shift on the applied light wavelength, power intensity, and nanowire diameter. (a) The redshift of resonance frequency increases with decreasing light wavelength, while no frequency shift is found for the light with wavelengths of 655 nm and 910 nm. The inset is PL spectrum of CdS nanowire for reference. (b) The redshift of resonance frequency increases with increasing light power, while no frequency shift is found for the light illumination with wavelength of 655 nm even at much higher light power. (c) The redshift of resonance frequency becomes larger for CdS nanowires with smaller diameters (light source: wavelength 405 nm, power: 16 mW/cm².