Real-time terahertz near-field microscope

We report a terahertz near-field microscope with a high dynamic range that can capture images of a 370 x 740 mu m(2) area at 35 frames per second. We achieve high spatial resolution (14 mu m corresponding to lambda/30 for a center frequency at 0.7 THz) on a large area by combining two novel techniques: terahertz generation by tilted-pulse-front excitation and electro-optic balanced imaging detection using a thin crystal. To demonstrate the microscope capability, we reveal the field enhancement at the gap position of a dipole antenna after the irradiation of a terahertz pulse. (C) 2011 Optical Society of America