CAJ | 학술논문

石英增强光声光谱技术（QEPAS）出现时间较晚，是一种较为新颖的痕量气体探测手段，本文以大气中的水汽作为测量目标，开展对基于QEPAS技术的痕量气体探测系统的研究。理论上，首先对激光器波长调制及信号谐波探测的原理进行了分析，得到了可用于气体浓度信号反演及激光器波长锁定的实现方案，并讨论了可用于高灵敏度气体探测的吸收谱线的选择原则。实验中，以输出波长为1.39μm的连续波分布反馈单纵模二极管激光器作为激发光源，采用激光器波长调制和2次谐波探测技术，首先研究了激光波长调制深度对QEPAS系统产生的信号幅度的影响，接下来对声波探测系统中微共振腔强声波增强特性进行了研究。QEPAS系统经过优化后，获得了5.9 ppm的探测极限，同时对不同浓度的水汽进行了测量，实验数据线性拟合后，得到R‐Square为0.98，证明了此QEPAS系统具有良好的线性响应度。最后，运用基于3次谐波探测的激光器波长锁定技术，对大气中的水汽变化进行了长达12 h的连续测量，实验结果表明，该系统性能稳定，具有良好的连续测量能力，可广泛应用于其他痕量气体的高灵敏度连续在线测量的研究上。
석영증강광성광보기술（QEPAS）출현시간교만，시일충교위신영적흔량기체탐측수단，본문이대기중적수기작위측량목표，개전대기우QEPAS기술적흔량기체탐측계통적연구。이론상，수선대격광기파장조제급신호해파탐측적원리진행료분석，득도료가용우기체농도신호반연급격광기파장쇄정적실현방안，병토론료가용우고령민도기체탐측적흡수보선적선택원칙。실험중，이수출파장위1.39μm적련속파분포반궤단종모이겁관격광기작위격발광원，채용격광기파장조제화2차해파탐측기술，수선연구료격광파장조제심도대QEPAS계통산생적신호폭도적영향，접하래대성파탐측계통중미공진강강성파증강특성진행료연구。QEPAS계통경과우화후，획득료5.9 ppm적탐측겁한，동시대불동농도적수기진행료측량，실험수거선성의합후，득도R‐Square위0.98，증명료차QEPAS계통구유량호적선성향응도。최후，운용기우3차해파탐측적격광기파장쇄정기술，대대기중적수기변화진행료장체12 h적련속측량，실험결과표명，해계통성능은정，구유량호적련속측량능력，가엄범응용우기타흔량기체적고령민도련속재선측량적연구상。
Quartz‐enhanced photoacoustic spectroscopy (QEPAS) technology was invented lately .Therefore it’s an innovative method for trace gas detection compared with other existed technologies .In this paper ,we studied the trace gas detection system based on QEPAS ,and the atmospheric H2 O was selected as the target analyte .In theory ,the principles of laser wavelength modulation and signal harmonic detection were analyzed firstly ,and the realizing solutions for the gas concentration retrieving and laser wavelength locking were obtained .Furthermore ,the selection principle of absorption line for high sensitivity gas detec‐tion was discussed .In experiments ,a continuous‐wave distributed feedback(DFB) single mode diode laser emitting at 1.39 μm was used as the exciting source for the H2 O vapor measurement .Using wavelength modulation spectroscopy and 2nd harmonic detection ,the influence of laser wavelength modulation depth on QEPAS signal level was investigated ,and the acoustic wave en‐hancement of the addition of micro‐resonator in the acoustic detection module was analyzed as well .After optimization of the QEPAS system ,a detection limit of 5.9 ppm for H2 O vapor was obtained .We measured the H2 O vapor with different concen‐trations ,and the R‐Square of 0.98 was achieved after the experimental data was linear fitted ,indicated that the QEPAS system had an excellent linear response ability .Finally ,continuous monitoring of atmospheric H2 O concentration levels for a period of 12 hours was performed when the line locking mode was employed with the help of 3rd harmonic detection .The experimental re‐sults showed that this QEPAS scheme had a stable performance and outstanding continuous measuring capacity ,and it can be widely used in high sensitivity on‐line measurement for other trace gases detection fields .