A research group at Tokyo University of Agriculture and Technology has applied a high-intensity femtosecond laser pulse to the surface of "silicon," which is a semiconductor material widely used in electronic devices, to cause a collective vibration phenomenon of electrons-surface plasmon polar trin-. Was observed for the first time in the world.
Surface plasmon polaritrin (hereinafter referred to as SPP) is a well-known phenomenon that occurs when free electrons collectively vibrate when a metal is irradiated with light.Since it can generate a strong electric field in the surroundings, it is used in various applications such as high-sensitivity photodetectors and high-efficiency solar cells.
On the other hand, it has been said that SPP cannot be generated in insulators and semiconductors that do not have free electrons. In the 1980s, the theory that "there is a condition that the solid surface can be metallized to generate SPP when irradiated with high-intensity laser light" was proposed, but it has not been proved.
This time, the research group conducted an experiment to irradiate a silicon diffraction grating with a femtosecond laser pulse (laser light that exists only between 1 femtosecond and less than 1 picosecond), and generated SPP at the interface between silicon and the atmosphere. Was caught for the first time.By utilizing this phenomenon, SPP can be generated on various solid surfaces simply by irradiating with laser light, and the solid surface can be directly scraped off by the strong electric field generated around the electrons.Micrometer size was the minimum limit for conventional processing technology using laser light, but this result is expected to realize unprecedented laser "nano" processing technology.
Paper information:[Physical Review B] Excitation of surface plasmon polaritons on silicon with an intense femtosecond laser pulse
