Rapid coherent Raman hyperspectral imaging based on delay-spectral focusing dual-comb method and deep learning algorithm

Rapid coherent Raman hyperspectral imaging shows great promise for applications in sensing, medical diagnostics, and dynamic metabolism monitoring. However, the spectral acquisition speed of current multiplex coherent anti-Stokes Raman scattering (CARS) microscopy is generally limited by the spectrometer integration time, and as the detection speed increases, the signal-to-noise ratio (SNR) of single spectrum will decrease, leading to a terrible imaging quality. In this Letter, we report a dual-comb coherent Raman hyperspec-tral microscopy imaging system developed by integrating two approaches, a rapid delay-spectral focusing method and deep learning. The spectral refresh rate is exploited by focusing the relative delay scanning in the effective Raman excitation region, enabling a spectral acquisition speed of 36 kHz, approximate to 4 frames/s, for a pixel resolution of 95 x 95 pixels and a spectral bandwidth no less than 200 cm(-1). To improve the spectral SNR and imaging quality, the deep learning models are designed for spectral preprocessing and automatic unsupervised feature extraction. In addition, by changing the relative delay focusing region of the comb pairs, the detected spectral wavenumber region can be flexibly tuned to the high SNR region of the spectrum. (c) 2023 Optica Publishing Group

Automated summary

Rapid coherent Raman hyperspectral imaging has potential applications in sensing, medical diagnostics, and dynamic metabolism monitoring. However, current multiplex coherent anti-Stokes Raman scattering (CARS) microscopy is limited by the spectrometer integration time, resulting in decreased signal-to-noise ratio (SNR) and poor imaging quality. This study presents a dual-comb coherent Raman hyperspectral microscopy system that combines a rapid delay-spectral focusing method and deep learning to achieve a spectral acquisition speed of 36 kHz, approximately 4 frames/s, with improved SNR and imaging quality.