High field, high efficiency terahertz pulse generation by optical rectification


The great difficulty of producing high intensity radiation in the terahertz (THz) spectral region by conventional electronics has stimulated interest in development of sources based on photonics. Optical rectification in lithium niobate is an attractive approach, because it supports high generation efficiencies, uses low cost, bulk LN crystals, and is powered by common Yb-doped lasers at wavelengths of around 1 Pm. In this work, a theoretical framework for THz generation by optical rectification is developed. Several novel methods for optimizing the generation efficiency are shown, including pump beam imaging, pump pulse optimization, cryogenic cooling, and THz antirefiection coating. Finally, experimental results will be presented showing a THz generation efficiency of 3.7%, which is 10x higher than current state-of-the-art. The generated few-cycle THz pulses can be used for coherent control of electrons, setting the stage for compact, table-top accelerators.

Masters Thesis