Finesse is a critical parameter for describing the characteristics of an optical enhancement cavity(OEC). This paper first presents a review of finesse measurement techniques, including a comparative analysis of the a...Finesse is a critical parameter for describing the characteristics of an optical enhancement cavity(OEC). This paper first presents a review of finesse measurement techniques, including a comparative analysis of the advantages, disadvantages, and potential limitations of several main methods from both theoretical and practical perspectives. A variant of the existing method called the free spectral range(FSR) modulation method is proposed and compared with three other finesse measurement methods, i.e., the fast-switching cavity ring-down(CRD) method, the rapidly swept-frequency(SF) CRD method, and the ringing effect method. A high-power OEC platform with a high finesse of approximately 16000 is built and measured with the four methods. The performance of these methods is compared, and the results show that the FSR modulation method and the fast-switching CRD method are more suitable and accurate than the other two methods for high-finesse OEC measurements. The CRD method and the ringing effect method can be implemented in open loop using simple equipment and are easy to perform. Additionally, recommendations for selecting finesse measurement methods under different conditions are proposed, which benefit the development of OEC and its applications.展开更多
腔衰荡光谱技术(Cavity Ring Down Spectroscopy,CRDS)具有高精度和高灵敏度,是一种常应用于微量气体浓度检测的方法,而采用这项技术的关键就是衰荡时间的准确获取。本文为此设计一种基于LabVIEW的腔衰荡信号在线处理系统,实现对衰荡信...腔衰荡光谱技术(Cavity Ring Down Spectroscopy,CRDS)具有高精度和高灵敏度,是一种常应用于微量气体浓度检测的方法,而采用这项技术的关键就是衰荡时间的准确获取。本文为此设计一种基于LabVIEW的腔衰荡信号在线处理系统,实现对衰荡信号的实时采集、平均、拟合、显示和保存。采用外部调制二极管激光器和高反腔搭建CRDS装置,获取实际的衰荡信号,用该系统处理测得的衰荡信号与其他软件的处理结果对比。实验表明,所编写的在线腔衰荡信号处理系统,可实现对衰荡时间的准确获取。展开更多
Near-infrared continuous wave cavity ring-down spectroscopy was applied to mea- sure the OH radicals in dielectric barrier discharge plasmas, which play an important role in combustion systems, atmospheric chemistry a...Near-infrared continuous wave cavity ring-down spectroscopy was applied to mea- sure the OH radicals in dielectric barrier discharge plasmas, which play an important role in combustion systems, atmospheric chemistry and the removal of air pollutants by non-thermal plasmas. The P-branches of OH X2YIi （vI ： 2 ＋-- it 0） bands were used for number density measurements. The OH number density and plasma temperature were determined for different applied voltages, gas pressures and concentrations of both oxygen and water. The temporal evolu- tion of the OH number density was obtained by using the ＂time window＂ method, which was used to extract individual ring-down times at different times in a half period of the sine wave applied voltage in dielectric barrier discharge plasmas.展开更多
We present a novel four-mirror cavity with two active gains to combine power intracavity and also give a detailed theoretical analysis of the combined gain. By using the effective field method, the four-mirror cavity ...We present a novel four-mirror cavity with two active gains to combine power intracavity and also give a detailed theoretical analysis of the combined gain. By using the effective field method, the four-mirror cavity with two gain media can be regarded as a linear resonator with one effective combined gain （ECG）, and we procure a theoretical model of the ECG and deduce its exact analytical expression. When the two branch gains are close to each other; the combined gain can be reduced to their product; and the simplified presentation of ECG has been demonstrated. The combined output power which directly reflects the small signal ECG of the four-mirror cavity is studied experimentally; and the results are in good agreement with the theoretical ones.展开更多
基金supported by the National Natural Foundation of China(No.21827804,No.22103075,No.22173089)the National Key R&D Program of China(No.2021YFA0716801,No.2017YFA0303502)。
基金jointly supported by the National Natural Science Foundation of China(No.22273093,No.41905018,No.21903080)the Ministry of Science and Technology of China(No.2022YFF0606500)。
基金Project supported by National Key Research and Development Program of China (Grant No.2022YFA1603403)。
文摘Finesse is a critical parameter for describing the characteristics of an optical enhancement cavity(OEC). This paper first presents a review of finesse measurement techniques, including a comparative analysis of the advantages, disadvantages, and potential limitations of several main methods from both theoretical and practical perspectives. A variant of the existing method called the free spectral range(FSR) modulation method is proposed and compared with three other finesse measurement methods, i.e., the fast-switching cavity ring-down(CRD) method, the rapidly swept-frequency(SF) CRD method, and the ringing effect method. A high-power OEC platform with a high finesse of approximately 16000 is built and measured with the four methods. The performance of these methods is compared, and the results show that the FSR modulation method and the fast-switching CRD method are more suitable and accurate than the other two methods for high-finesse OEC measurements. The CRD method and the ringing effect method can be implemented in open loop using simple equipment and are easy to perform. Additionally, recommendations for selecting finesse measurement methods under different conditions are proposed, which benefit the development of OEC and its applications.
文摘腔衰荡光谱技术(Cavity Ring Down Spectroscopy,CRDS)具有高精度和高灵敏度,是一种常应用于微量气体浓度检测的方法,而采用这项技术的关键就是衰荡时间的准确获取。本文为此设计一种基于LabVIEW的腔衰荡信号在线处理系统,实现对衰荡信号的实时采集、平均、拟合、显示和保存。采用外部调制二极管激光器和高反腔搭建CRDS装置,获取实际的衰荡信号,用该系统处理测得的衰荡信号与其他软件的处理结果对比。实验表明,所编写的在线腔衰荡信号处理系统,可实现对衰荡时间的准确获取。
基金supported by National Natural Science Foundation of China (Nos.10475015, 10975029)
文摘Near-infrared continuous wave cavity ring-down spectroscopy was applied to mea- sure the OH radicals in dielectric barrier discharge plasmas, which play an important role in combustion systems, atmospheric chemistry and the removal of air pollutants by non-thermal plasmas. The P-branches of OH X2YIi （vI ： 2 ＋-- it 0） bands were used for number density measurements. The OH number density and plasma temperature were determined for different applied voltages, gas pressures and concentrations of both oxygen and water. The temporal evolu- tion of the OH number density was obtained by using the ＂time window＂ method, which was used to extract individual ring-down times at different times in a half period of the sine wave applied voltage in dielectric barrier discharge plasmas.
文摘We present a novel four-mirror cavity with two active gains to combine power intracavity and also give a detailed theoretical analysis of the combined gain. By using the effective field method, the four-mirror cavity with two gain media can be regarded as a linear resonator with one effective combined gain （ECG）, and we procure a theoretical model of the ECG and deduce its exact analytical expression. When the two branch gains are close to each other; the combined gain can be reduced to their product; and the simplified presentation of ECG has been demonstrated. The combined output power which directly reflects the small signal ECG of the four-mirror cavity is studied experimentally; and the results are in good agreement with the theoretical ones.
基金V. ACKNOWLEDGMENTS We are indebted to D. Romanini and S. Kassi for helpful discussion. This work was supported by the National Natural Science Foundation of China （No.20903085 and No.20533060）, Chinese Ministry of Science and Technology （No.2006CB922001 and No.2007CB815203）, and the Fok Ying Tong Education Foundation （No. 101013）.
文摘一个洞铃流分光计(CRDS ) 与单个模式的连续波浪的 Ti 被构造：蓝宝石激光。它允许达到 1.8 楶楳整 ? 楷桴愠嘠牥 ? 敓獮瑩癩? 慃楶祴删湩 ?潤湷匠数瑣潲敭整 r 致 ? 致的最小的可检测的吸收吗？？
