基于光电标定校准的太赫兹辐射功率计量标准研究

Terahertz (THz) technology has been widely used in material detection, astronomical observation, remote sensing, biomedical imaging, and homeland security. Precisely traceable measurements of THz radiant power are urgently needed for the development and applications of THz technology. This project focuses on the theoretical and experimental investigations of THz radiometry, including traceable theory, measurement standard fabrication technique, and detector calibration technology. We aim to realize accurately traceable measurement of THz radiant power with optical power calibration and electrical power reproduction. For the international problem of THz difficult to be absorbed, we propose a THz standard detector design technique with highly absorptive coating and cavity absorption structure. With this technique, THz radiation is anticipated to be totally absorbed, and it can be accurately calibrated with optical power. For the traditional problem of detector sensitivity changes with ambient temperature and humidity, we put forward an electrical calibration method. This method applies an electrical heating film embedded in the absorber to precisely replace the measured THz power with electrical power, and thus on-site reproduction and absolute measurement of THz power can be achieved. With above studies and investigations, a novel THz radiant power measurement standard based on optical and electrical calibrations will be constructed, with which the measurement ability is improved. This standard would provide traceable measurements for THz detectors in the applications in chemistry, astronomy, sensing, communications and security. New THz power measurement comparison ability and calibration and measurement capability (CMC) will be established, and it will promote the development of THz metrology, improve the characterization of THz radiation, and guarantee the applications of THz technology.

太赫兹技术不断应用于材料探测、天文观测、卫星遥感、安检成像和军事国防等领域，这些应用亟需精准掌握和测量太赫兹辐射基本特性。本项目拟开展太赫兹辐射功率计量研究，创新地利用光功率标定和电功率校准实现太赫兹功率精准复现，解决太赫兹功率绝对测量和量值溯源问题。针对太赫兹辐射不易被吸收的国际难题，提出高吸收涂层和腔型吸收标准器研制技术，实现光功率精准替代太赫兹功率；针对太赫兹探测器响应度随环境变化的传统问题，提出绝对型嵌入式电校准方法，实现电功率现场精确复现太赫兹功率；利用光电双重校准技术，研制太赫兹辐射功率计量标准，实现我国太赫兹功率精准计量。通过项目研究，预期可形成新的太赫兹功率计量方法和标准装置，提升我国太赫兹计量能力，促进太赫兹技术在各领域应用；新增太赫兹功率国际比对能力和国际互认校准测量能力，保障国际太赫兹量值准确统一，促进太赫兹计量学的发展，增进对太赫兹电磁辐射特性的认知。

太赫兹技术在材料探测、天文观测、卫星遥感、安检成像等领域具有广泛而重要的应用，这些应用亟需精准掌握和测量太赫兹辐射基本特性，而太赫兹功率是太赫兹最基本、最重要的基本特性之一。本项目开展太赫兹辐射功率计量研究，研制了双腔型太赫兹绝对辐射功率计。项目研制的太赫兹绝对辐射计具有两个吸收腔，分别用于精准复现激光辐射功率和太赫兹辐射功率。项目研制了具有超薄的电加热膜，作为绝对辐射计嵌入式电校准的关键器件，与超薄激光吸收涂层相结合，具有良好的光电等效性，实现了良好的激光辐射功率和电功率等效替代，利用电加热功率精准复现了激光辐射功率。项目研制了在太赫兹波段具有宽波段高吸收率的混合吸收材料，实现了太赫兹辐射的高吸收，通过腔型结构进一步提高了绝对辐射计的腔体吸收率。太赫兹辐射功率复现腔具有良好的激光和太赫兹功率等效性，通过嵌入式超薄电加热膜实现了太赫兹辐射功率的电替代功率复现。通过比较太赫兹辐射功率复现腔和激光辐射功率复现腔，利用激光功率标定和电功率校准，实现了太赫兹辐射吸收腔光电不等效性的标定校准，精准复现了太赫兹辐射功率。测量太赫兹激光器的实验结果表明，研制的太赫兹绝对辐射计与中国计量科学研究院的太赫兹功率标准具有良好的一致性。项目发表期刊论文8篇，会议论文4篇，获得授权发明专利2项，获市场监管科研成果二等奖1项，中国仪器仪表学会科学技术进步奖一等奖1项。项目研制的太赫兹辐射计降低了太赫兹功率测量不确定度，提升了我国太赫兹功率计量准确度水平。项目研制的太赫兹绝对辐射计作为量值溯源的源头，对太赫兹辐射源和太赫兹功率计开展精准测试和精确标定，保障了太赫兹功率量值在物质识别、高速通讯、天文观测、生物医学、公共安全等领域应用的准确统一，促进了太赫兹技术研究和应用的发展。