High-speed high-sensitivity infrared spectroscopy using mid-infrared swept lasers (Conference Presentation)
High-speed high-sensitivity infrared spectroscopy using mid-infrared swept lasers (Conference Presentation)
复制标题
使用中红外扫频激光器的高速高灵敏度红外光谱（会议演示）
DOI：
10.1117/12.2209300
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Childs D
中科院分区：
文献类型：
--
作者：
Childs D
红外光谱是一种非常有吸引力的生物医学样本成分分析读出技术，因为它具有高分子灵敏度的独特组合，无需外源标记。 FTIR 和拉曼等传统技术的速度和灵敏度相对较低，但最近的创新正在挑战这种情况。直接中红外光谱技术的创新正在加速，例如基于 MEMS 的 FTIR 仪器，具有非常高的镜速和超连续谱源，可产生非常高的样品辐照水平。在这里，我们探索另一种可能的方法 - 具有高腔调谐速度（中红外扫频激光器）的外腔量子级联激光器（EC-QCL）。扫频激光器在近红外领域得到了大力发展，用于无损低相干成像 (OCT)。我们以两种方式调整这些概念。首先，通过将中红外量子级联增益芯片与采用 OCT 的外腔设计相结合，我们实现了接近 1 kHz 的光谱采集率，并展示了达到 100 kHz 的潜力。其次，我们证明中红外扫频激光器与近红外 OCT 扫频激光器具有基本的灵敏度优势。这使得它们有可能在其他匹配的条件下，在更短的 N 倍时间（N 是光谱点的数量）内实现与 FTIR 仪器相同的光谱 SNR。这种效应通过 PDMS 样品的测量得到证明。 潜在的非常高的光谱采集率、基本的信噪比优势和低成本探测器系统的使用相结合，可以使中红外扫频激光器成为高通量生物医学光谱学的强大技术。
Infrared spectroscopy is a highly attractive read-out technology for compositional analysis of biomedical specimens because of its unique combination of high molecular sensitivity without the need for exogenous labels. Traditional techniques such as FTIR and Raman have suffered from comparatively low speed and sensitivity however recent innovations are challenging this situation. Direct mid-IR spectroscopy is being speeded up by innovations such as MEMS-based FTIR instruments with very high mirror speeds and supercontinuum sources producing very high sample irradiation levels. Here we explore another possible method – external cavity quantum cascade lasers (EC-QCL’s) with high cavity tuning speeds (mid-IR swept lasers). Swept lasers have been heavily developed in the near-infrared where they are used for non-destructive low-coherence imaging (OCT). We adapt these concepts in two ways. Firstly by combining mid-IR quantum cascade gain chips with external cavity designs adapted from OCT we achieve spectral acquisition rates approaching 1 kHz and demonstrate potential to reach 100 kHz. Secondly we show that mid-IR swept lasers share a fundamental sensitivity advantage with near-IR OCT swept lasers. This makes them potentially able to achieve the same spectral SNR as an FTIR instrument in a time x N shorter (N being the number of spectral points) under otherwise matched conditions. This effect is demonstrated using measurements of a PDMS sample. The combination of potentially very high spectral acquisition rates, fundamental SNR advantage and the use of low-cost detector systems could make mid-IR swept lasers a powerful technology for high-throughput biomedical spectroscopy.