| 摘要 |
PROBLEM TO BE SOLVED: To realize a terahertz radar apparatus capable of measuring a distance, in a short time. SOLUTION: A mode-locked frequency control means 12 stabilizes the mode-locked frequencies of femtosecond lasers 10 and 11 to make the difference between their mode-locked frequencies constant. A pumping light from the femtosecond laser 10 is made incident onto a photoconducting antenna 13 to generate a terahertz com. Probe light from the femtosecond laser 11 is made incident on a photoconducting antenna 14, and the terahertz com reflected from an object X to be measured is made incident onto the photoconducting antenna 14 to form an RF com. A phase difference meter 17 extracts the com mode of the RF com and measures the phase of an extracted com mode, to compute the distance to the object X to be measured. By selecting and extracting a plurality of com modes, it is possible to achieve high-dynamic range distance measurements. COPYRIGHT: (C)2011,JPO&INPIT
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