Characteristics of the Terahertz sources suitable for biomedical applications

In the electromagnetic spectrum, Terahertz (THz) radiation is located between the infrared and microwave regions. As a result of recent advances in THz technology, numerous opportunities have opened up in this part of the spectrum. The THz frequency range stimulates substantial amplitude vibrational modes of molecules. Water has strong absorptions at THz frequencies and water being a major constituent of different biological specimens, THz radiation is likely to demonstrate significant characteristic distinction between them. Terahertz pulsed imaging (TPI) and terahertz pulsed spectroscopy (TPS) are non-ionizing and non-invasive analyzing technique that have recently been used to study a wide range of biological materials, and have been shown to have potential in medical and biological applications. Despite this enormous potential, little research has been conducted made on appropriate THz sources for biomedical applications. The power levels and frequencies suitable are still not well-defined. In this paper, we summarize some of the available THz sources, applied power levels of irradiation, and suitable frequency ranges that have been utilized in particular studies and discuss the findings regarding tissue identification, disease detection, and cancer diagnosis.