Abstract

This study presents a novel technique for generating terahertz (THz) waves with frequency modulation capabilities ranging from linear sweeping to random hopping. Departing from conventional methods that utilize wavelength-tunable lasers to produce optical waves with variable frequency differences, this approach harnesses an optical frequency comb to generate optical wave frequencies at fixed intervals. Crucially, it employs a uniquely configured optical filter with adjustable dual passbands, allowing for the selection of optical beats with frequency variances that are multiples of the comb's interval. These beats are subsequently converted into THz waves using a THz photomixer, aligning the THz frequency with the adjustable interval between the filter's passbands. This innovation significantly enhances the versatility and scope of THz wave frequency modulation, offering substantial potential for advancements in high-speed communication, precision imaging, and spectroscopy.