Quantum cascade lasers (QCL) are the first room temperature semiconductor laser source for the mid-IR spectral region, triggering substantial development for the advancement of mid-IR spectroscopy. Mid-IR spectroscopy in general provides rapid, label-free and objective analysis, particularly important in the field of biomedical analysis. Due to their unique properties, QCLs offer new possibilities for development of analytical methods to enable quantification of clinically relevant concentration levels and to support medical diagnostics. Compared to FTIR spectroscopy, novel and elaborated measurement techniques can be implemented that allow miniaturized and portable instrumentation. This review illustrates the characteristics of QCLs with a particular focus on their benefits for biomedical analysis. Recent applications of QCL-based spectroscopy for analysis of a variety of clinically relevant samples including breath, urine, blood, interstitial fluid, and biopsy samples are summarized. Further potential for technical advancements is discussed in combination with future prospects for employment of QCL-based devices in routine and point-of-care diagnostics.

中文翻译：

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生物医学光谱学中的量子级联激光器（QCL）

量子级联激光器（QCL）是用于中红外光谱区域的第一个室温半导体激光源，触发了中红外光谱学发展的实质性发展。中红外光谱通常提供快速，无标记和客观的分析，在生物医学分析领域尤其重要。由于其独特的性能，QCL为分析方法的开发提供了新的可能性，从而能够量化临床上相关的浓度水平并支持医学诊断。与FTIR光谱相比，可以实施新颖且精细的测量技术，从而可以实现小型化和便携式仪器。这篇综述阐述了QCL的特征，特别关注它们在生物医学分析中的优势。总结了基于QCL的光谱学在分析各种临床相关样品（包括呼吸，尿液，血液，组织液和活检样品）中的最新应用。结合在常规和即时诊断中使用基于QCL的设备的未来前景，对技术进步的进一步潜力进行了讨论。