Open AccessTransient transmission of THz metamaterial antennas by impact ionization in a silicon substrate
Author(s) -
Matías Bejide,
Yejun Li,
N. Stavrias,
Britta Redlich,
Takuo Tanaka,
Vũ Đình Lãm,
Nguyễn Thanh Tùng,
Ewald Janssens
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.405555
Subject(s) - materials science , optoelectronics , metamaterial , terahertz radiation , picosecond , impact ionization , silicon , substrate (aquarium) , optics , charge carrier , ionization , laser , physics , ion , oceanography , quantum mechanics , geology
The picosecond dynamics of excited charge carriers in the silicon substrate of THz metamaterial antennas was studied at different wavelengths. Time-resolved THz pump-THz probe spectroscopy was performed with light from a tunable free electron laser in the 9.3-16.7 THz frequency range using fluences of 2-12 J/m 2 . Depending on the excitation wavelength with respect to the resonance center, transient transmission increase, decrease, or a combination of both was observed. The transient transmission changes can be explained by local electric field enhancement, which induces impact ionization in the silicon substrate, increasing the local number of charge carriers by several orders of magnitude, and their subsequent diffusion and recombination. The studied metamaterials can be integrated with common semiconductor devices and can potentially be used in sensing applications and THz energy harvesting.