369
7
Terahertz Radiation:
Sources,
Applications, and
Biological Effects
7.1 Introduction .......................................................... 370
The Terahertz Region: Fundamental Units with
Biological Relevance • Nonionizing Radiation:
“X-Rays” versus “T-Rays” • Spectroscopic
Fingerprint Region for Biological Materials
7.2 ­ Terahertz Sources: Conventional and
State-of-the-Art..................................................... 375
Direct Generation Laser Sources • Electronic
Solid-State Terahertz Devices: Frequency
Up-Conversion • Accelerating Electron-Based
Terahertz Sources • Nonlinear Optical Terahertz
Sources: Frequency Down-Conversion
7.3 ­ Terahertz Applications.........................................385
Spectroscopy • Imaging
7.4 ­ Terahertz Skin Interactions.................................389
Skin Anatomy • Fundamental Principles of
Terahertz-Tissue Optics • Optical Properties
of Skin • Photothermal Mechanisms and
Classic Heat Transfer • Thermal History:
Temperature Damage Zones and Associated
Biological Effects • Tissue Damage at Terahertz
Frequencies • Terahertz Safety Standards
7.5 ­ Biological Effects at a Cellular and
Biomolecular Level ...............................................400

Background on Cellular Stress Response and
Cellular Death • Terahertz Bridge—The First
International Project on Terahertz Bioeffects
(2001–2004) • Recent Studies on Terahertz
Bioeffects (2004–2010) • Cellular Effects
Gerald J. Wilmink
of Terahertz Radiation
Jessica E. Grundt