Hannover 2016 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 42: Poster: Quantum Optics and Photonics III

Q 42.47: Poster

Wednesday, March 2, 2016, 16:30–19:00, Empore Lichthof

Optical ablation of gold bowtie nanoantenna — •Liping Shi — Welfengarten1

We experimentally demonstrate the optical ablation of gold bowtie nanoantenna under the irradiation of laser pulses output from Ti: Sapphire femtosecond oscillator. The temporal behavior of third harmonic enhancement factor from bowtie antennas is introduced to determine durability of nanostructure. We observed two different channels of optical ablation from gold bowtie nanoantenna: thermal effects induced melting and near-field enhancement induced ion ejection. It is shown that by employing thicker nanoantenna can significantly increase the thermal damage fluence threshold, but the optical ablation originated from field emission is inevitable in vacuum. However, our experiments show that if the nanoantenna are exposed in air, this field emission can be dramatically suppressed, which might be attributed to the adsorption of gas molecules at sharp features of field-enhancing structures. We also numerically employed the two-temperature model to estimate the free electrons as well as gold lattice temperature, and solved the one-dimensional heat diffusion equation to simulate the spatial and temporal distribution of temperature in substrate sapphire.