SBIR Phase II: Compact THz-ABCD Spectrometer

NSF小型企业创新研究第二阶段项目建议开发一种紧凑型太赫兹-ABCD(空气偏置相干检测)。基于一种利用环境空气和选定气体中的激光感应等离子体产生和测量超宽带太赫兹波的新技术的光谱仪。脉冲能量为100UJ，脉冲宽度为100飞秒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(300kV/cm)、高方向性(6度)和超宽带(10%带宽从0.1到10THz)的太赫兹波。通过这种相互作用过程，空气或选择的气体也可以作为超宽带传感器，通过空气偏置相干检测(ABCD)产生脉冲太赫兹波。从0.3到10太赫兹(波长1 mm~30微米)的电磁频谱区域现在是物理、化学、生物、材料科学和医学研究的前沿领域。近年来，对激光诱导大气等离子体中太赫兹波的产生和探测的观测为遥感和光谱研究提供了新的手段。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(频谱范围为0.1至30太赫兹)、灵敏度(外差法)和频谱分辨率(MHz)，这些在以前被认为是不可能同时实现的。此外，这项技术产生的太赫兹电场强度接近1 mV/cm，释放了传统光学实验室设施以前无法获得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。无损检测、层析成像、无标记遗传分析、细胞级成像、爆炸物检测和化学/生物传感等应用将太赫兹研究从相对默默无闻推向了新的高度。拟议开发的紧凑型太赫兹ABCD光谱仪将为跨学科研究提供关键的使能技术。此外，它还将推动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)产生直接影响，对国土安全的短期应用(3至5年)和生物医学部门的长期兴趣(5至10年)产生直接影响。如果成功，该项目的成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.