For the first time, this study unveils the enigma behind the noiselike patterns superimposed over the signal of photothermal lensing spectroscopy that has emerged as a powerful tool for nondestructive evaluation. The single-beam thermal lens (TL) signal of a sample (illustrated using ethylene glycol) is recorded using an ultrasensitive photodetector and a digital storage oscilloscope. The signal exhibits fluctuations superimposed that the photothermal spectroscopic community considered as noise so far, limiting the accuracy of the technique. The comprehensive analysis carried out helps in decoding the mystery behind the superimposed fluctuations in TL signal, affirming the nonwhite noise (WN) nature of the signal and emphasizing that they carry valuable information. These findings not only challenge preconceived assumptions but also unveil novel pathways, offering new perspectives that enhance our understanding of the dynamics within the medium in the realm of TL spectroscopy and are deciphered with literature support.

中文翻译：

---

探索谜团：解码热透镜信号中的噪声模式背后的奥秘


这项研究首次揭示了叠加在光热透镜光谱信号上的类噪声图案背后的谜团，光热透镜光谱已成为无损评估的强大工具。使用超灵敏光电探测器和数字存储示波器记录样品的单光束热透镜 (TL) 信号（使用乙二醇进行说明）。该信号表现出叠加的波动，迄今为止光热光谱界认为这是噪声，限制了该技术的准确性。进行的综合分析有助于解开 TL 信号叠加波动背后的谜团，确认信号的非白噪声 (WN) 性质，并强调它们携带有价值的信息。这些发现不仅挑战了先入为主的假设，而且揭示了新的途径，提供了新的视角，增强了我们对TL光谱领域介质动态的理解，并在文献支持下进行了解读。