Spectral Range Broadening of Multimode-Laser-Driven Terahertz Spectroscopy System Using Two Laser Diodes

We built a terahertz time-domain spectroscopy system that utilizes two continuous-wave multimode laser diodes with slightly different central wavelengths. We obtained intensified continuous terahertz waves using two multimode laser diodes compared with the case of only one laser diode. The spectral bandwidth of the generated THz wave extended up to 0.5 THz, which was broader than the 0.2 THz bandwidth obtained by 1 laser diode.