Terahertz notch filter using intermolecular hydrogen bonds in a sucrose crystal.
We propose a THz notch filter that uses the absorption of the intermolecular hydrogen bonds in a molecular crystal such as sucrose. Terahertz (THz) time-domain spectroscopy was used to investigate the absorption characteristics of a rotationally oriented sucrose single crystal in the 0.3 - 3.0 THz frequency range. The crystal was set so that the (100) face (cleavage) was normal to the THz propagation direction. The two lowest frequency intermolecular hydrogen bonding bands clearly exist at room temperature and at 1.45 and 1.64 THz when the b-axis of the crystal is parallel and perpendicular to the THz polarization, respectively. In contrast, they disappear when the b-axis is reversed. This absorption feature means that it would be possible to utilize a sucrose crystal as a notch filter with a 1.45-THz band center for the 0.1-1.7 THz range and with a 1.64-THz band center for the 0.1-1.9 THz range. When the crystal is rotated, the transmitted intensities of the frequency components near the absorption bands alternate as a sine function against angle. The spectroscopic properties of the sucrose filter were confirmed by continuous THz wave imaging.
Rungsawang
Rakchanok
R
Ueno
Yuko
Y
Tomita
Isao
I
Ajito
Katsuhiro
K