van Leeuwen Nicola J, Diettrich Jan C, Wilson Andrew C
Department of Physics, University of Otago, P.O. Box 56, Dunedin, New Zealand.
Appl Opt. 2003 Jun 20;42(18):3670-7. doi: 10.1364/ao.42.003670.
We demonstrate a simple periodically locked cw cavity ringdown spectroscopy technique that enables a very large number of ringdown events to be rapidly acquired. An external cavity diode laser is locked to a high-finesse cavity, and as many as 16,000 ringdown events per second are obtained by periodically switching off the light entering the high-finesse cavity. Following each ringdown event, the light to the cavity is switched back on and cavity lock is rapidly reacquired. Limited only by our relatively modest digitization rate, we obtained a minimum detectable absorption loss of 4.7 x 10(-9) cm(-1), but we show that faster digitization could provide a sensitivity of 5.9 x 10(-10) cm(-1) Hz(-1/2).
我们展示了一种简单的周期性锁定连续波腔衰荡光谱技术，该技术能够快速获取大量的衰荡事件。一个外腔二极管激光器被锁定到一个高精细度的腔上，通过周期性地关闭进入高精细度腔的光，每秒可获得多达16000次衰荡事件。在每次衰荡事件之后，进入腔的光被重新打开，并且迅速重新获得腔锁定。仅受我们相对适中的数字化速率限制，我们获得了4.7×10⁻⁹ cm⁻¹的最小可检测吸收损耗，但我们表明更快的数字化能够提供5.9×10⁻¹⁰ cm⁻¹ Hz⁻¹/²的灵敏度。
