CAJ | 학술논문

稳定同位素比值的测量在地质学、气象学和地球科学的研究中具有蕈要的应用价值.水汽同位素丰度的测量对理解与干旱相关的同温层大气科学具有重要的意义.水汽分子在2.7 μm附近具有较强的吸收,适宜于高灵敏度光谱的测量.文章报道了利用差频技术(Difference frequency generation)和准相位匹配技术(Quasi-phase matching),将调}皆范围在750～840 nm之间的连续可调谐钛宝石激光器和单频连续的Nd:YAG敫光器,耦合到周期性极化铌酸锂非线性光学晶体中,产生2.5～4 μn波段的中红外可调谐激光.选择周期为20μm的PPLN品体,产生2.7 μm附近的中红外差频激光,利用差频产生的中红外激光光源,具有窄线宽、宽调谐等优点.结合光程为100 m的Herriott型多通吸收池,采用直接吸收光谱方法测量了实验窒大气中的水汽分子同位素,得到了同位素比值R及~(17)O,~(18)O,D的丰度值δ,实验所测R值与国际标准具有很好的一致性.
은정동위소비치적측량재지질학、기상학화지구과학적연구중구유심요적응용개치.수기동위소봉도적측량대리해여간한상관적동온층대기과학구유중요적의의.수기분자재2.7 μm부근구유교강적흡수,괄의우고령민도광보적측량.문장보도료이용차빈기술(Difference frequency generation)화준상위필배기술(Quasi-phase matching),장조}개범위재750～840 nm지간적련속가조해태보석격광기화단빈련속적Nd:YAG교광기,우합도주기성겁화니산리비선성광학정체중,산생2.5～4 μn파단적중홍외가조해격광.선택주기위20μm적PPLN품체,산생2.7 μm부근적중홍외차빈격광,이용차빈산생적중홍외격광광원,구유착선관、관조해등우점.결합광정위100 m적Herriott형다통흡수지,채용직접흡수광보방법측량료실험질대기중적수기분자동위소,득도료동위소비치R급~(17)O,~(18)O,D적봉도치δ,실험소측R치여국제표준구유흔호적일치성.
Stable-isotope ratio analysis of water is an important tool for geology, meteorology, and earth sciences. Measure-ments of water vapor isotopes are very helpful to explaining stratospheric aridity and related issues in atmospheric sciences. The absorption of water vapor near 2. 7μm is very strong so it is suitable for measuring high sensitivity spectra. Based on difference frequency generation and quasi-phase matching, by mixing an Nd : YAG laser with Ti : Sapphire tunable from 750 to 840 nm in a 50 mm long periodically poled lithium niobate (PPLN) crystal, a widely tunable CW laser source was generated for the mid-in-frared spectral range from 2.5 to 4 μm. We chose A = 20 μm for PPLN crystal, the generated laser was around 2. 7 μm. This laser is widely tunable and of inherent narrow linewidth based on difference-frequency generation. Using this idler laser and 100 m multi-pass cell, and direct absorption the water vapor isotopes were measured in the laboratory air. The authors measured iso-topes ratios and δ~(17)O, δ~(18)O and δD. The values were found to be in excellent agreement with the standard value for three individ-ual lines.