Abstract-Imaging of Chemical Reactions Using a Terahertz Chemical Microscope

Toshihiko Kiwa  , Tatsuki Kamiya , Taiga Morimoto , Kentaro Fujiwara , Yuki Maeno , Yuki Akiwa, Masahiro Iida, Taihei Kuroda, Kenji Sakai, Hidetoshi Nose, Masaki Kobayashi, Keiji Tsukada

https://www.mdpi.com/2304-6732/6/1/10

This study develops a terahertz (THz) chemical microscope (TCM) that visualizes the distribution of chemical reaction on a silicon-based sensing chip. This chip, called the sensing plate, was fabricated by depositing Si thin films on a sapphire substrate and thermally oxidizing the Si film surface. The Si thin film of the sensing plate was irradiated from the substrate side by a femtosecond laser, generating THz pulses that were radiated into free space through the surface field effect of the Si thin film. The surface field responds to chemical reactions on the surface of the sensing plate, changing the amplitude of the THz pulses. This paper first demonstrates the principle and experimental setup of the TCM and performs the imaging and measurement of chemical reactions, including the reactions of bio-related materials

Abstract-Evaluation of Bio-materials Using a Laser-excited Terahertz Wave

Toshihiko Kiwa, Tatsuki Kamiya, Masahiro Iida, Hirofumi Inoue, Kenji Sakai, Shinichi Toyooka, Keiji Tsukada,

https://www.jstage.jst.go.jp/article/jslsm/39/4/39_jslsm-39_0031/_article/-char/en

We have developed various types of terahertz sensing systems for evaluation of bio-related materials. Here, we describe a terahertz chemical microscopy that we have invented and demonstrate a label-free immune assay and evaluation of penetration speed of cosmetic liquid, each of which was realized using different way of use of the terahertz chemical microscopy.

Abstract-pH measurements in 16-nL-volume solutions using terahertz chemical microscopy

Toshihiko Kiwa, Tatsuki Kamiya, Taiga Morimoto, Kenji Sakai, and Keiji Tsukada

https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-26-7-8232

Terahertz chemical microscopy has been developed for measuring the pH of a solution using only a small volume. The microsolution wells were fabricated on the surface of the sensing plate using a conventional photolithograph technique. Because the pH value can be calculated from the amplitude of a terahertz wave directly radiated from a sensing plate by a femtosecond laser irradiation, this method does not require any reference electrode in the solution. Thus, pH measurement can be achieved with a volume as small as 16 nL.

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