Detection of weak near-infrared optical imaging signals under ambient light by optical parametric amplification.
Detection of weak near-infrared optical imaging signals under ambient light by optical parametric amplification.
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DOI：
10.1364/ol.44.004391
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发表时间：
2019-08
期刊：
影响因子：
3.6
通讯作者：
Yi Sun;H. Tu;Sixian You;Chi Zhang;Y. Liu;S. Boppart
中科院分区：
文献类型：
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作者：
Yi Sun;H. Tu;Sixian You;Chi Zhang;Y. Liu;S. Boppart
提出了一种基于光学参量放大的近红外光学成像信号放大检测方法。采用周期性极化铌酸锂晶体作为光学参量放大器，为光学参量放大过程提供了良好的准相位匹配条件。利用OPA将1465 nm处的弱反射成像信号放大到高达92 dB的高增益，利用低成本光电探测器在环境光条件下对放大后的光信号进行检测。如此高的增益导致在5 MHz检测带宽下的检测极限为23 pW，这明显低于近红外光电倍增管（PMT）的理论值。通过利用OPA的优点，显微镜或成像所需的入射功率降低了40-60 dB。OPA的高成像增益还可以选择性地检测深层组织结构反射的微弱信号，从而显著提高成像穿透深度。OPA的成功实施使一种强大而灵敏的检测方法成为可能，在近红外光谱范围内的成像应用中取代pmt。
We present a detection method based on optical parametric amplification to amplify and detect near-infrared (NIR) optical imaging signals. A periodically poled lithium niobate crystal is employed as an optical parametric amplifier (OPA), which provides excellent quasi-phase-matching conditions for the optical parametric amplification process. A weak reflectance imaging signal at 1465 nm is amplified by the OPA with a high gain of up to 92 dB, and the amplified optical signal is detected with a low-cost photodetector under ambient light conditions. Such a high gain leads to a detection limit of 23 pW under a 5 MHz detection bandwidth, which is remarkably lower than the theoretical value of a NIR photomultiplier tube (PMT). By exploiting the advantages of the OPA, the incident power needed for microscopy or imaging is reduced by 40-60 dB. The high imaging gain of the OPA also significantly enhances the imaging penetration depth by selectively detecting the weak signal reflected from deep tissue structures. The successful implementation of the OPA enables a robust and sensitive detection method that offers the potential to replace PMTs in imaging applications within the NIR spectral range.