Single-cycle terahertz electromagnetic pulses: A new test bed for physical seismic modeling

摘要

We describe a new technique for physical modeling, based on the use of short pulses of electromagnetic radiation. We employ radiation at a frequency near 1 THz (10~(12) Hz), corresponding to a wavelength of ～0.3 mm. Very recent advances in optoelectronic techniques have enabled the generation and detection of broadband terahertz pulses using compact room- temperature transducers. These pulses can be used to form images in a variety of modes, including a multistatic reflection configuration which mimics that of many seismic surveys. We illustrate the capabilities of the modeling technique with a simple experiment which demonstrates accurate surface reconstruction using migration techniques. With respect to conventional modeling techniques using piezoelectric transducers and microphones, the use of terahertz pulses has both benefits and limitations. To our knowledge, this work represents the first use of electromagnetic radiation for modeling acoustic imaging problems.