The terahertz (THZ) region of electromagnetic spectrum is often described as the nal unexplored area of spectrum. First, humans relied on the radiation from the sun. Cave men used torches (approximately 500,000 years ago). Candles appeared around 1000 BC, followed by gas lighting (1772), and incandescent bulbs (Edison, 1897). Radio (1886-1895), X-rays (1895), UV radiation (1901), and radar (1936) were invented at the end of the nineteenth and the beginning of the twentieth centuries. However, THz range of electromagnetic spectrum still presents a challenge for both electronic and photonic technologies.