Choi, Geunchang Kang, Taehee Seo, Minah Kim, Dai-Sik Bahk, Young-Mi 2024-01-19T21:04:56Z 2024-01-19T21:04:56Z 2021-09-05 2018-12 2330-4022 https://pubs.kist.re.kr/handle/201004/120619 We demonstrate photoexcited carrier response of metallic nanogap-patterned semiconductor using optical pump-terahertz probe spectroscopy. Metallic nanogap facilitates observing surface carrier dynamics of bulk semiconductors by means of strong field confinement and enhancement of electromagnetic waves at nanoscale. Here, we observe that the enhanced terahertz transmission change of photoexcited InP has a nonmonotonic behavior (increases and then decreases) as reducing the gap size, which originates from different field confinement of near-infrared light (pump) and terahertz waves (probe). This 5 observation is theoretically reproduced by our simple model which informs that one can obtain the maximum pump probe signal at the condition in which the field overlapping of two different electromagnetic waves used in the pump probe experiment becomes maximized. Our results pave the way toward designing nanogap-based optical devices operated by multiwavelength electromagnetic waves. English AMER CHEMICAL SOC TERAHERTZ DYNAMICS LIGHT GAAS SPECTROSCOPY NANOANTENNAS ABSORPTION Enhanced Surface Carrier Response by Field Overlapping in Metal Nanopatterned Semiconductor Article 10.1021/acsphotonics.8b00724 1 ACS PHOTONICS, v.5, no.12, pp.4739 - 4744 ACS PHOTONICS 5 12 4739 4744 scie scopus 000454463000003 2-s2.0-85058813657 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Optics Physics, Applied Physics, Condensed Matter Science & Technology - Other Topics Materials Science Optics Physics Article TERAHERTZ DYNAMICS LIGHT GAAS SPECTROSCOPY NANOANTENNAS ABSORPTION optical pump-terahertz probe spectroscopy semiconductor surface metallic gap field overlap