SBIR Phase II: Compact THz-ABCD Spectrometer

NSF小企业创新研究第二阶段项目建议开发一种紧凑的太赫兹- abcd（空气偏置相干探测）。利用激光诱导等离子体在环境空气和选定气体中产生和测量超宽带太赫兹波的新技术。100 uJ脉冲能量和100飞秒脉冲持续时间的聚焦光脉冲在气体中产生等离子体（电离气体分子），在远场产生非常强烈（300千伏/厘米），高度定向（6度）和超宽带（10%带宽从0.1到10太赫兹）太赫兹波。通过互反过程，空气或选定的气体也可以通过空气偏置相干探测（ABCD）作为脉冲太赫兹波的超宽带传感器。从0.3到10太赫兹（波长1毫米至30微米）的电磁波谱区域现在是物理学、化学、生物学、材料科学和医学研究的前沿领域。近年来，激光诱导大气等离子体中太赫兹波的产生和探测为遥感和光谱学研究提供了新的方法。使用空气作为太赫兹波发射器和传感器提供了前所未有的带宽（0.1至30太赫兹的光谱范围），灵敏度（外差法）和光谱分辨率（MHz），这些以前被认为是不可能同时实现的。此外，该技术产生的太赫兹电场强度接近1 MV/cm，解锁了传统光学实验室设施以前无法实现的非线性太赫兹光谱的潜力。利用空气/气体发射、控制、增强和测量宽带太赫兹波的最新进展开辟了一系列研究机会。包括无损检测、层析成像、无标签遗传分析、细胞水平成像、爆炸物探测和化学/生物传感在内的应用将太赫兹研究从相对默默无闻推向了新的高度。提出的紧凑太赫兹ABCD光谱仪的开发将为跨学科研究提供关键的使能技术。此外，它将推进太赫兹频率范围内的许多传感和成像概念，对非破坏性光谱分析（例如：药物研发，材料研究），近期（3至5年）应用于国土安全以及长期（5至10年）生物医学领域产生直接影响。如果成功，这个项目的结果将对学术和政府实验室合作、学生教育和仪器开发做出重大贡献。

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. 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.