Active tailoring of nanoantenna plasmonic fields using few-cycle laser pulses

• Main Authors: Choi, S., Ciappina, M. F., Pérez-Hernández, J. A., Landsman, A. S., Kim, Y.-J., Kim, S. C., Kim, Dong Eon
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Article
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering::Mechanical engineering; Center Wavelength; Pulse Repetition Rate
• Online Access: https://hdl.handle.net/10356/89565; http://hdl.handle.net/10220/46308
• Institution: Nanyang Technological University

Plasmonic nanoatennas are a versatile tool for coherently manipulating light on a nanoscale by confining electric fields of the driving laser into subwavelength volumes, thereby significantly enhancing electric near fields. It is normally assumed that the time-dependent spectral properties of these near fields are independent of the duration of the driving laser pulse. Here we show that when a few-cycle laser pulse shines on a bow-tie nanoantenna, its spectral properties are dramatically modified, as evidenced by a large shift of the center wavelength of the near field, relative to the driving laser. In addition, for certain geometries, a second color appears in the near field, creating conditions for generation of an isolated attosecond pulse at megahertz repetition rate. Our results open the door to frequency-tunable ultrafast sources at nanometer scale without tuning the frequency of the driving laser.