Spectral Response Tuning of Photoconductive Terahertz Emitters With Binary Phase Masks

In this paper, binary phase masks are designed and implemented for use with a photoconductive terahertz (THz) emitter in order to shape the frequency response of the emitted THz waveforms. Theoretical and experimental results are applied to study the system. The theoretical results are presented in the form of both numerical simulations (to characterise and uniquely identify the underlying time-delayed photogeneration and resulting charge-carrier dynamics) and a simplified model (to conceptualise the system). The theoretical and experimental results are found to agree. It is ultimately shown that the phase delay through the binary phase mask can be used to preferentially allocate power into bands within the THz spectrum. Such results can lay the groundwork for future studies needing precise control of power within the THz spectrum.