Optical frequency combs, which are generated by the cascade of a phase modulator and a Mach-Zehnder intensity modulator, are used as a polychromatic signal source in the terahertz imaging system to improve imaging quality. Interference effect caused by the monochromatic wave has been greatly suppressed. The required optical power in the presented system is as low as ~30% of that in the system using the Er-doped fiber amplifier as source, which can reduce cost and protect photodiodes from damage. This work provides an effective, low power consumption, low cost, and easy way to realize terahertz imaging with high quality, and can be used in the future security inspection.
SHAO DIXIANG, Chen Yao, Zhou T., Zhang R., FU ZHANGLONG, Zhuang Songlin, Cao Juncheng. Terahertz imaging using optical frequency combs source[J]. Chinese Optics Letters, 2019, 17(4): .