Laser terahertz emission microscopy

Laser terahertz (THz) emission microscopy (LTEM) is reviewed. Femtosecond lasers can excite THz waves in various electronic materials due to ultrafast current modulation. The current modulation is realized by the acceleration or deceleration of photo-excited carriers, and thus LTEM visualizes the dynamic photo-response of substances. We construct a free-space type and scanning probe type with transmission or reflection modes. The developed systems have a minimum spatial resolution better than 2 μm, which is defined by the laser beam diameter. We present some examples of LTEM applications, such as ferroelectric domain imaging, quantitative supercurrent distribution in high- T c superconductors, defect detection of MOS devices as well as the visualization of the photo-responses in materials and devices. To cite this article: H. Murakami, M. Tonouchi, C. R. Physique 9 (2008).