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A new real-time terahertz imaging system has been developed by using a quantum cascade laser source and a microbolometer focal plane detector array. The application to non-invasive analyses of cultural heritage is demonstrated with an oil paint specimen. The experimental results suggested that the terahertz imaging system can identify materials based on a spectral database with a spatial resolution of about 300 µm. The transmission imaging indicated the difference between natural and artificial ultramarine pigments. Since the size of the system is similar to a common portable infrared camera, it can be used at the place where the object is located, such as museums, and can contribute to conservation activities, such as drying process monitoring. This real-time, small, non-invasive terahertz imaging system can be used in various fundamental research fields and practical industries.

Terahertz imaging has attracted much attention in recent years, because the technique can be applied to many application fields such as nondestructive analysis and imaging method through opaque materials. A terahertz real-time imaging technique (Terahertz Camera) considered increasingly important in the future has been developed. The terahertz camera consists of a light source (Terahertz quantum cascade laser) and an un-cooled micro-bolometer array, which can easily get real-time terahertz-image. As an application of the terahertz camera, a stand-off imaging system that could be useful in a fire disaster relief and a label-free bio-materials detection system have developed and demonstrated.

Bolometer-type uncooled infrared QVGAs (Quarter Video Graphics Arrays, namely, 320x240) were modified to improve their sensitivities at 3 THz. High transmission materials were investigated and it is found that high resistivity Silicon with anti-reflection coating of Parylene or Silicon Dioxide is suitable. Using this material, THz lens was fabricated and handy THz camera which operates at TV frame rate was also fabricated. Using the THz camera, NEP (Noise Equivalent Power) of uncooled THz-QVGA sensor was characterized at several wavelengths from 3 to 270 m. The THz camera showed THz imageries of antigen-antibody reaction without labeling molecules, which indicate that THz detection technology can be promising for detecting proteins.