Plasmonics-enhanced terahertz spectroscopy (Conference Presentation)

Abstract

Although unique potentials of terahertz waves for chemical identification and material characterization have been recognized for quite a while, the relatively poor performance of current terahertz spectroscopy and spectrometry systems continue to impede their deployment in field settings. This talk describes some of the recent advancements in terahertz spectroscopy systems by using optically-pumped plasmonic photoconductors for terahertz wave generation and detection. Incorporating plasmonic nanostructures inside the active area of photoconductive terahertz sources and detectors offers enhanced quantum efficiencies while maintaining ultrafast operation. This enhancement is due to the unique capability of plasmonic nanostructures to significantly increase the concentration of photo-induced carriers inside the device active area, where they interact with a bias/terahertz electric field to generate/detect terahertz radiation. By the use of this powerful technique, broadband terahertz spectroscopy with record-high signal-to-noise ratio levels exceeding 140 dB and broadband terahertz spectrometry with quantum-level sensitivities are demonstrated. Such high-sensitivity terahertz spectroscopy and spectrometry systems could offer numerous opportunities for e.g., biomedical sensing, atmospheric studies, astrophysics studies, pharmaceutical quality control, and security screening applications.