1.55 microm Indium Gallium Arsenide THz Synchronized Photoconductive Switch Array.

摘要

Metal-particle-in-semiconductor nanocomposites are of continuing interest in materials science to produce electronic, photonic, and thermoelectric devices, as well as chemical and biological nanosensors. These materials have successfully been employed for THz photoconductive devices operating at 800 nm. To date, producing devices operating at the desirable pump wavelength of 1.55 microm at which both mode-locked and single-frequency lasers needed for THz generation are readily available, remains challenging. Excessive dark current and prohibitively low breakdown voltage have been the primary impediments. Recent research has shown that ErAs:In0.53Ga0.47As designed for subpicosecond photoconductivity exhibits an exponential increase in resistivity when cooled to temperatures below 250 K. This increased resistivity gives promise to producing THz sources since higher bias voltages can be used, thus increasing the optical to THz conversion efficiency.;One of the major limitations of THz photoconductive sources is that it is challenging to harness sizeable power. Typical power levels generated by THz sources at 1.55 microm are generally in the low microwatts region. This dissertation demonstrates a 1.55 microm THz synchronized linear array that maximizes power and has attained an impressive maximum peak power of 123 microW. In addition, THz beam steering at 1.55 microm by phase control in the time domain is a young field. Beam steering is demonstrated with this phased array up to 14.6° using optical delay line units. The possibility of beam steering will prove beneficial in various applications, particularly in standoff imaging.