The first integrated database of terahertz data in the world opened on September 15 at RIKEN and the Next Generation Network Center at the National Institute of Information and Communications Technology (NICT) (www.thzdb.org). By consolidating the terahertz spectra of various materials, such as research reagents and paint materials, the database allows researchers to access a wide variety of useful data for use in both basic research and practical applications.
Terahertz radiation has recently been found to be extremely useful, as it can penetrate such materials as clothing, paper, wood, plastic and ceramics, but cannot pass through metal or water. This makes it potentially extremely useful in imaging and non-destructive testing, as well as in security and for finding illegal drugs.
When materials are irradiated with terahertz light and then examined with a spectroscope, the absorption spectrum is different depending on the material—this is the material’s ‘fingerprint spectrum’. The new database contains hundreds of these fingerprint spectra, which researchers can use to identify materials, such as medicines, illicit drugs or agricultural chemicals, as well as reagents and chemicals contained in the material.
Moreover, containers that are opaque to visible light, such as bags and envelopes, are often transparent in the terahertz spectrum. This makes it possible to find dangerous articles without opening the container, by combining the unique nature of the sample’s spectrum with the penetrative properties of terahertz light. This enables, for example, non-destructive inspection of luggage and food packaging.
Art historians are also using terahertz data to ascertain the appearance of early drafts of paintings under many layers of paint. The fingerprint spectra of over 200 kinds of paint materials were included in the database.
The integrated terahertz database was constructed by a research consortium comprising the RIKEN Advanced Science Institute and NICT. RIKEN and NICT researchers integrated data on the terahertz spectra of about 500 kinds of materials from previous databases and modified it to make it easier to use.
RIKEN is also cooperating with outside organizations, including Italy’s National Agency for New Technologies, Energy and the Environment, to improve and expand the data, and aims to have about 2,000 entries by 2010.