Mid-infrared photoacoustic brain imaging enabled by cascaded gas-filled hollow-core fiber lasers

作者：Cuiling Zhang, Kunyang Sui, Marcello Meneghetti, José Enrique Antonio-Lopez, Manoj K. Dasa, Rune W. Berg, Rodrigo Amezcua‐Correa, Yazhou Wang, Christos Markos · 发表于：Neurophotonics · 年份：2024 · DOI：10.1117/1.nph.11.4.045012 · 被引用次数：8 · 研究领域：Photoacoustic and Ultrasonic Imaging、Optical Coherence Tomography Applications、Random lasers and scattering media

SignificanceExtending the photoacoustic microscopy (PAM) into the mid-infrared (MIR) molecular fingerprint region constitutes a promising route toward label-free imaging of biological molecular structures. Realizing this objective requires a high-energy nanosecond MIR laser source. However, existing MIR laser technologies are limited to either low pulse energy or free-space structure that is sensitive to environmental conditions. Fiber lasers are promising technologies for PAM for their potential to offer both high pulse energy and robust performance, which however have not yet been used for PAM because it is still at the infant research stage.AimWe aim to employ the emerging gas-filled anti-resonant hollow-core fiber (ARHCF) laser technology for MIR-PAM for the purpose of imaging myelin-rich regions in a mouse brain.ApproachThis laser source is developed with a high-pulse-energy nanosecond laser at 3.4μm, targeting the main absorption band of myelin sheaths, the primary chemical component of axons in the central nervous system. The laser mechanism relies on two-order gas-induced vibrational stimulated Raman scattering for non-linear wavelength conversion, starting from a 1060-nm pump laser to 3.4 μm through the two-stage gas-filled ARHCFs.ResultsThe developed fiber Raman laser was used for the first time for MIR-PAM of mouse brain regions containing structures rich in myelin. The high peak power of ∼1.38 kW and robust performance of the generated MIR Raman pulse addressed th...