摘要 |
<p>Methods and apparatus (10, 20, 25, 60, 70) for detecting variations in electromagnetic fields, in particular, terahertz (THz) electromagnetic fields, are provided. The methods and apparatus employ polarization detection devices (120) and controllers (224) to maintain or vary the polarization of modulated signals (212, 262) as desired. The methods and apparatus are provided to characterize electromagnetic fields by directing the electromagnetic field (204, 254) and a probe beam (206, 252) upon an electro-crystal (202, 256) and detecting the modulation of the resulting probe beam (212, 262). Detection of the modulation of the probe beam (212, 262) is practiced by detecting and comparing the polarization components (216, 218, 266, 268) of the modulated probe beam (212, 262). Aspects of the invention may be used to analyze or detect explosives, explosive related compounds, and pharmaceuticals, among other substances. A compact apparatus (10), modular optical devices (20, 25, 60, 70) for use with the apparatus, sample holders (400, 402, 500), and radiation source mounts (600, 650, 700) are also disclosed.</p> |
申请人 |
RENSSELAER POLYTECHNIC INSTITUTE;SCHULKIN, BRIAN;ZHANG, XI-CHENG;TONGUE, THOMAS;XU, JINGZHOU;CHEN, JIAN |
发明人 |
SCHULKIN, BRIAN;ZHANG, XI-CHENG;TONGUE, THOMAS;XU, JINGZHOU;CHEN, JIAN |