Dielectric Relaxation Spectroscopy
The dielectric relaxation spectroscopy measures the dielectric constant of a sample as a function of frequency. It is based on the interaction of external electromagnetic field with the dipole moment of the sample. We focused on the rotational relaxation of water molecules lies in GHz (slow water) to THz (fast water) range.
Vector Network Analyzer (VNA) with Open-Ended Coaxial Dielectric Probe
The open-ended dielectric probe (Keysight) is used to determines the dielectric constant of liquid samples such as salts or biomolecular solutions with an Anritsu Vector Star network analyzer. The slim form probe has a frequency range of 0.5 GHz to 40 GHz.
Ternary Liquid Calibration Method
Instead of widely used calibration method (air, metal and short), three reference liquid is used for calibration protocol. After home-built calibration and optimization process, it gives reliable results for both low and high polarizable liquids (Measured: Circles, From literatures: Lines).
Terahertz Time-Domain Spectroscopy
The commercial Advantest THz time-domain spectroscopy (Advantest) with ATR geometry is used to determine dielectric constants of liquid samples such as salts or biomolecular solutions from 0.25 THz to 1.5 THz frequency range with precise temperature control.
The home-built THz time-domainspectroscopy using photoconductive antenna is used to measure dielectric constant of solid or liquid samples with transmission geometry.
Ultrafast THz Pump/Probe Spectroscopy for Water
The ultrafast THz pump – optical/THz probe spectroscopy is used to measure the ultrafast dynamics of water around biological molecules such as lipids and DNA. For the THz generation, the DSTMS organic crystal is used to obtain field intensity above 1 MV/cm. (under construction)