Near-field enhancement of the nanostructure on the fused silica with rigorous method

• Published in: Applied optics. Optical technology and biomedical optics Vol. 54; no. 14; p. 4318
• Main Authors: Wang, Hu, Qi, Hongji, Wang, Bin, Cui, Yanyan, Chai, Yingjie, Jin, Yunxia, Yi, Kui, Shao, Jianda
• Format: Journal Article
• Language: English
• Published: United States 10.05.2015
• ISSN: 2155-3165
• DOI: 10.1364/AO.54.004318

A rigorous electromagnetic method is developed to analyze the resonance effect of near field caused by nanoscale subsurface defects, which play a key role in describing absorption enhancement during laser-matter interaction for transparent dielectric materials. The total electric field calculated with this new method is consistent with the result of finite-difference time-domain simulation. The concept of mode amplitude density spectrum is developed to analyze the specific modes of the total field. A new mode parameter is proposed to demarcate the contribution of the resonance. The frequency space is divided into four parts and the resonance effect is analyzed as well as the contributions of different modes to the total field. The influence of the structure parameters on the near-field modulation and energy transference is also discussed. It is found that the enhancement mechanism of the near-field and local absorption is the resonance effect caused by the total internal reflection on the sidewall of the nanostructure. In addition, the surrounding energy is mainly guided into the structure by the root of the structure via the energy flow analysis.