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A terahertz microfluidic chip which was fabricated out of quartz and polydimethylsiloxane (PDMS) was designed. The quartz acted as a substrate, on which a microfluidic channel with a height of 50 micrometer was etched by lithography technology. PDMS is a kind of easy fabricated and cheap polymer to cover the quartz substrate. It’s widely used in microfluidic applications for its numerous characteristics such as good insulation, colorlessness and transparency, high-voltage endurance and excellent optical quality. The transmittance of the chip was measured first. Increasing the frequency from 0.2 THz to 1.4 THz decreases the transmittance of microfluidic chip rapidly, where reaches as high as 80% when the frequency is 0.2 THz. The chip shows a high transmittance of above 40% from the range from 0.2 THz to 0.8 THz. Then THz spectra of glycerol, water and their mixture in the microfluidic chip were measured, respectively. Not only the time domain spectra but frequency-dependent amplitude spectra present significant differences of different kinds of liquids and different concentrations of the same glycerol. The absorption spectra result shows a monotonic increase in the absorption coefficient of the glycerol, water and the mixture with increasing frequency, respectively. It matches the fact that different molecules or the same molecules of different concentrations present different absorption coefficients in the terahertz band. All of the above indicate that this microfluidic chip is available in measurement of the samples in liquid and it’s able to realize real-time and label-free measurement for biochemistry samples in terahertz time-domain-spectroscopy(THz-TDS). Since the depth of the micro-channel is 50 μm，the detectable liquid in the chip only has an value of less than 10 μL, microfluidic chips offer a new platform for performing THz spectroscopy of small quantities of biomolecules using low-power THz sources.
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