Vibrational mid-infrared photothermal spectroscopy using a fiber laser probe: asymptotic limit in signal-to-baseline contrast
Vibrational mid-infrared photothermal spectroscopy using a fiber laser probe: asymptotic limit in signal-to-baseline contrast
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DOI：
10.1364/ol.41.000179
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发表时间：
2016-01-01
期刊：
影响因子：
3.6
通讯作者：
Sander, Michelle Y.
中科院分区：
文献类型：
--
作者：
Totachawattana, Atcha;Liu, Hui;Sander, Michelle Y.
报道了一个由近红外光纤探测激光器和可调谐量子级联泵浦激光器组成的中红外光热光谱系统。测量了6 μ m厚的4-辛基-4 ′-氰基联苯液晶样品的光热光谱，其信号与基线的对比度大于10（3）。由于峰值光热信号和相应的基线都随探测功率线性增加，因此对于给定的泵浦功率，信号与基线的对比度收敛到渐近极限。该限制与探头功率无关，并表征系统可实现的最佳对比度。这使得能够直接从光热光谱测量中灵敏地定量表征线性红外吸收特征。(C)2015年美国光学学会。
We report on a mid-infrared photothermal spectroscopy system with a near-infrared fiber probe laser and a tunable quantum cascade pump laser. Photothermal spectra of a 6 mu m-thick 4-octyl-4'-cyanobiphenyl liquid crystal sample are measured with a signal-to-baseline contrast above 10(3). As both the peak photothermal signal and the corresponding baseline increase linearly with probe power, the signal-to-baseline contrast converges to an asymptotic limit for a given pump power. This limit is independent of the probe power and characterizes the best contrast achievable for the system. This enables sensitive quantitative spectral characterization of linear infrared absorption features directly from photothermal spectroscopy measurements. (C) 2015 Optical Society of America.