Coherent Raman spectro-imaging with laser frequency combs
Coherent Raman spectro-imaging with laser frequency combs
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DOI：
10.1038/nature12607
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发表时间：
2013-10-17
期刊：
影响因子：
64.8
通讯作者：
Haensch, Theodor W.
中科院分区：
文献类型：
--
作者：
Ideguchi, Takuro;Holzner, Simon;Haensch, Theodor W.
光谱学和显微镜的进步对物理、化学和生物科学产生了深远的影响。一个例子是相干拉曼光谱，一种多功能的技术，询问分子中的振动跃迁。它提供了高空间分辨率和三维切片能力，使其成为非破坏性和化学选择性探测复杂系统的无标记工具（1，2）。事实上，单色拉曼波段已在生物组织中成像视频率（3，4）通过使用超短脉冲激光。然而，识别多个可能未知的分子需要宽光谱带宽和高分辨率。使用多通道检测（5）或频率扫描激光束（6-9），结合高速采集的中等光谱跨度现在已经触手可及。发现激光频率梳（10）越来越多地用于宽带分子线性吸收光谱（11-15）。在这里，我们通过探索它们在非线性光谱学（16）中的潜力，表明它们可以用于相干反斯托克斯拉曼光谱学和光谱成像。该方法使用两个梳，可以同时测量，微秒的时间尺度上，所有的光谱元素在一个单一的光电探测器上的宽带宽和高分辨率。虽然在我们的原理验证实验中，总体测量时间受到连续光谱采集之间的等待时间的限制，但这种限制可以通过进一步的系统开发来克服。因此，我们希望我们的方法，使用激光频率梳将不仅使新的应用非线性显微镜，但也有利于其他非线性光谱技术。
Advances in optical spectroscopy and microscopy have had a profound impact throughout the physical, chemical and biological sciences. One example is coherent Raman spectroscopy, a versatile technique interrogating vibrational transitions in molecules. It offers high spatial resolution and three-dimensional sectioning capabilities that make it a label-free tool(1,2) for the non-destructive and chemically selective probing of complex systems. Indeed, single-colour Raman bands have been imaged in biological tissue at video rates(3,4) by using ultra-short-pulse lasers. However, identifying multiple, and possibly unknown, molecules requires broad spectral bandwidth and high resolution. Moderate spectral spans combined with high-speed acquisition are now within reach using multichannel detection(5) or frequency-swept laser beams(6-9). Laser frequency combs(10) are finding increasing use for broadband molecular linear absorption spectroscopy(11-15). Here we show, by exploring their potential for nonlinear spectroscopy(16), that they can be harnessed for coherent anti-Stokes Raman spectroscopy and spectro-imaging. The method uses two combs and can simultaneously measure, on the microsecond timescale, all spectral elements over a wide bandwidth and with high resolution on a single photodetector. Although the overall measurement time in our proof-of-principle experiments is limited by the waiting times between successive spectral acquisitions, this limitation can be overcome with further system development. We therefore expect that our approach of using laser frequency combs will not only enable new applications for nonlinear microscopy but also benefit other nonlinear spectroscopic techniques.