High-resolution terahertz tomography using 17-fs ultrashort-pulse fiber laser

We describe the generation and detection of coherent broadband terahertz waves using ultrashort-pulse fiber laser, and its application to terahertz tomography. A pulse compression technique using nonlinear and dispersion effects of optical fibers leads to the development of high-peak-power 17- fs ultrashort- pulse fiber laser. With the optical rectification in an organic crystal, 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST), ultra-broad terahertz pulses are successfully generated. The spectrum ranges widely from 0.1 to 25 THz. By applying these broadband THz pulses to THz tomography, the thickness of 5- mum thin Teflon film is measured correctly.