近日，四川大学的梁厚昆&彭飞及其研究小组与芬兰坦佩雷大学的Goëry Genty等人合作并取得一项新进展。经过不懈努力，他们实现中红外计算时间鬼成像。相关研究成果已于2024年5月28日在国际知名学术期刊《光：科学与应用》上发表。

该研究团队演示了一种频率下变频时间鬼成像方案，该方案能够将工作范围扩展到任意波长区域，特别是那些快速调制器和检测器不可用的光谱区域。该方法通过在近红外范围内调制具有时间强度模式的信号，并利用非线性晶体中的差频产生技术，将信号模式传输至闲置波长，进而在该波长处成功检索时间对象。

作为概念验证，研究人员成功展示了中红外计算时间鬼成像技术，其工作波长可灵活调谐至3.2 μm至4.3 μm之间。这一方案因其高度的灵活性，可扩展至其他光谱区域。这项研究结果为无扫描泵浦探针成像和光谱区域的超快动力学研究提供了新的可能性，其中超快调制或检测具有挑战性，如中红外和太赫兹区域。

据悉，时域鬼成像技术可运用慢速光电探测器来重建快速的时间对象。此技术关键在于将随机或预编程的探测时间强度模式，与经时间对象调制后测量的集成信号进行关联。然而，实现时间鬼成像通常需要超快探测器或调制器，来测量或预编程探测强度模式，这在所有光谱区域，特别是中红外范围内，并非总是可行。

附：英文原文

Title: Mid-infrared computational temporal ghost imaging

Author: Wu, Han, Hu, Bo, Chen, Lu, Peng, Fei, Wang, Zinan, Genty, Goery, Liang, Houkun

Issue&Volume: 2024-05-28

Abstract: Ghost imaging in the time domain allows for reconstructing fast temporal objects using a slow photodetector. The technique involves correlating random or pre-programmed probing temporal intensity patterns with the integrated signal measured after modulation by the temporal object. However, the implementation of temporal ghost imaging necessitates ultrafast detectors or modulators for measuring or pre-programming the probing intensity patterns, which are not available in all spectral regions especially in the mid-infrared range. Here, we demonstrate a frequency downconversion temporal ghost imaging scheme that enables to extend the operation regime to arbitrary wavelengths regions where fast modulators and detectors are not available. The approach modulates a signal with temporal intensity patterns in the near-infrared and transfers the patterns to an idler via difference-frequency generation in a nonlinear crystal at a wavelength where the temporal object can be retrieved. As a proof-of-concept, we demonstrate computational temporal ghost imaging in the mid-infrared with operating wavelength that can be tuned from 3.2 to 4.3 μm. The scheme is flexible and can be extended to other regimes. Our results introduce new possibilities for scan-free pump-probe imaging and the study of ultrafast dynamics in spectral regions where ultrafast modulation or detection is challenging such as the mid-infrared and THz regions.

DOI: 10.1038/s41377-024-01426-0

Source: https://www.nature.com/articles/s41377-024-01426-0