Product Code: ICA10_P115

Femtosecond Laser Near-Field Ablation Mediated with Mie Resonance Scattering by High Dielectric Constant Particles with Small Size Parameter
Authors:
Yuto Tanaka, Keio University, School of Integrated Design Engineering; Yukohama-shi Japan
Go Obara, Keio University, School of Integrated Design Engineering; Yokohama-shi Japan
Akira Zenidaka, Keio University, School of Integrated Design Engineering; Yokohama-shi Japan
Minoru Obara, Keio University, School of Integrated Design Engineering; Yokohama-shi Japan
Presented at ICALEO 2010

We present experimental and theoretical results on near-field nano-ablation mediated with Mie resonance scattering by high dielectric constant particles with small size parameter.
Theoretical FDTD calculations clarified that the maximal field enhancement factor and localized spot close to the smallest size are obtainable on both low-refractive-index (SiO2) and high-refractive-index (Si) substrates using a 200-nm diam. Mie resonance dielectric particle (n~2.7) at magnetic quadrupole mode with 400-nm excitation wavelength. Experimental results with 200-nm amorphous TiO2 particles (n=2.66+0.024i) by 400-nm femtosecond laser irradiation verified that clear circular nanoholes with 100 nm diam. approximately are fabricated on SiO2 and Si substrates even with laser fluences lower than a half the ablation threshold of the bare substrates.
Highly dense two-dimensional nanohole array was fabricated by applying arrayed particles template. Optical field interaction such as inter-particle multiple scattering should be considered and an optimal refractive index of particle is found different from a single particle system.
The obtained result confirms that application of high dielectric constant particles with optimal refractive index is a promising technique for downsizing the fabricated nanoholes and fabricating functional nanostructured surfaces.