NSF Award
0848811
This NSF Small Business Innovation Research Phase II project proposes to develop a compact THz-ABCD (air-biased coherent- detection). spectrometer based on a new technique for generating and measuring ultra-broadband THz waves utilizing a laser induced plasma in ambient air and selected gases. A focused optical pulse with >100 uJ pulse energy and <100 femtosecond pulse duration in gas creates a plasma (ionized gas molecules), which produces very intense (>300 kV/cm), highly-directional (<6 degree), and ultra-broadband (10% bandwidth from 0.1 to 10 THz) THz waves in the far field. Through the reciprocal process, air or selected gases also serve as an ultra-broadband sensor of pulsed THz waves through air-biased coherent- detection (ABCD).The region of the electromagnetic spectrum from 0.3 to 10 THz (1 mm - 30 um in wavelength) is now a frontier area for research in physics, chemistry, biology, materials science and medicine. Recently, the observations of THz wave generation and detection in the laser induced atmospheric plasma provide new method in remote sensing and spectroscopy. The use of air as THz wave emitter and sensor provides unprecedented bandwidth (spectral range of 0.1 to 30 THz), sensitivity (heterodyne method), and spectral resolution (<MHz) which were previously considered impossible to achieve simultaneously. In addition, this technique produces THz electric field strengths approaching 1 MV/cm, unlocking the potential for nonlinear THz spectroscopy previously inaccessible by conventional optics lab facilities. <br/><br/><br/>Recent advances in the use of air/gases to emit, control, enhance, and measure broadband THz waves open up a range of research opportunities. Applications including nondestructive testing, tomographic imaging, label-free genetic analysis, cellular level imaging, explosives detection, and chemical/biological sensing have thrust THz research, from relative obscurity, to new heights. The proposed development of a compact THz ABCD spectrometer will provide a key enabling technology for interdisciplinary research. In addition it will advance numerous sensing and imaging concepts in the THz frequency range, with an immediate impact on non-destructive spectroscopic analysis (eg: pharmaceutical R&D, materials research), a near-term application (3 to 5 years) for homeland security and a longer-term interest (5 to 10 years) in the biomedical sector. If successful the outcome of this project will make significant contributions to academic and governmental laboratory collaboration, student education, and instrumentation development.
