Real-time spectral imaging of protein films using a tunable THz laser source

The absorption spectrum of a protein, namely horse heart myoglobin, was measured by terahertz time-domain spectroscopy of up to 2.75 THz. High-power THz radiation from a tunable cw gas-vapour laser was used to perform two-dimensional imaging. Clear images of the protein film were obtained by monitoring it at the absorption peak frequency. Experimental results show that a spectral image of biological samples can be obtained by employing THz radiation in real time.