Femtosecond Laser Transfer of Silicon Nanoparticles with Enhanced Raman Response

摘要

High refractive index subwavelength dielectric nanoresonators, supporting electric and magnetic optical resonance, are basic elements for waveguiding, sensing, and nonlinear nanophotonic devices. However, high concentration of defects in the nanoresonators after the fabrication process diminishes their resonant properties, which are crucially dependent on their internal losses. Moreover, amorphous dielectric nanoparticles have broad and weak Raman signal. Here, we show that the fabrication of crystalline (low-loss) resonant silicon nanoparticles by femtosecond laser ablation of amorphous (high-loss) silicon thin films is possible. Also, we demonstrate experimentally a 140-fold enhancement of Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance.