Abstract
We propose a novel approach to generate a continuous-wave pulse train with an ultrahigh repetition rate. The method utilizes a unique mechanism of lightwave modulation and amplification based on a continuous-wave Raman interaction in a high-finesse optical cavity. We experimentally demonstrated the generation of multifrequency emissions from a hydrogen-filled cavity and measured the intensity-modulated waveform at the frequency of 17.6THz. We found that the intracavity dispersion caused phase mismatch between the related longitudinal modes; thus preventing the phase-locked generation of a continuous-wave-based THz pulse train. This undesirable behavior can be overcome by using a dispersion-managed and bandwidth-extended cavity; this will then lead to a new-type of mode-locked laser operating at a frequency of more than 10THz.
