title: Tunable resolution terahertz dual frequency comb spectrometer.
abstract: Terahertz dual frequency comb spectroscopy (THz-DFCS) yields high spectral resolution without compromising bandwidth. Nonetheless, the resolution of THz-DFCS is usually limited by the laser repetition rate, which is typically between 80 MHz and 1 GHz. In this paper, we demonstrate a new method to achieve sub-repetition rate resolution in THz-DFCS by adaptively modifying the effective laser repetition rate using integrated Mach-Zehnder electro-optic modulators (MZ-EOMs). Our results demonstrate that it is possible to improve the 100 MHz resolution of a terahertz frequency comb by at least 20x (down to 5 MHz) across the terahertz spectrum without compromising the average output power, and to a large extent, its bandwidth. Our approach can augment a wide range of existing THz-DFCS systems to provide a significant and easily adaptable resolution improvement.
authors.forename: Francisco S
authors.initials: FS
authors.lastname: Vieira
authors.forename: Flavio C
authors.initials: FC
authors.lastname: Cruz
authors.forename: David F
authors.initials: DF
authors.lastname: Plusquellic
authors.forename: Scott A
authors.initials: SA
authors.lastname: Diddams