Nordström Emil, Hosseinnia Ali, Brackmann Christian, Bood Joakim, Bengtsson Per-Erik
Opt Lett. 2015 Dec 15;40(24):5718-21. doi: 10.1364/OL.40.005718.
We report an innovative approach for time-domain measurements of S-branch Raman linewidths using hybrid picosecond/nanosecond pure-rotational coherent anti-Stokes Raman spectroscopy (RCARS). The Raman coherences are created by two picosecond excitation pulses and are probed using a narrow-band nanosecond pulse at 532 nm. The generated RCARS signal contains the entire coherence decay in a single pulse. By extracting the decay times of the individual transitions, the J-dependent Raman linewidths can be calculated. Self-broadened S-branch linewidths for nitrogen and oxygen at 293 K and ambient pressure are in good agreement with previous time-domain measurements. Experimental considerations of the approach are discussed along with its merits and limitations. The approach can be extended to a wide range of pressures and temperatures and has potential for simultaneous single-shot thermometry and linewidth determination.
我们报道了一种使用皮秒/纳秒混合纯转动相干反斯托克斯拉曼光谱（RCARS）对S支拉曼线宽进行时域测量的创新方法。拉曼相干由两个皮秒激发脉冲产生，并使用532 nm的窄带纳秒脉冲进行探测。所产生的RCARS信号在单个脉冲中包含了整个相干衰减。通过提取各个跃迁的衰减时间，可以计算出与J相关的拉曼线宽。在293 K和环境压力下，氮气和氧气的自加宽S支线宽与先前的时域测量结果吻合良好。本文讨论了该方法的实验考量及其优缺点。该方法可扩展到广泛的压力和温度范围，并且具有同时进行单次测温及线宽测定的潜力。
