Stray light analysis and suppression in microlens array-based spatial heterodyne Raman spectrometer

Spatial heterodyne Raman spectroscopy (SHRS), as a widely adopted material detection technique, achieves enhanced spatial resolution through the integration of microlens array (MLA). However, this advancement simultaneously introduces new stray light components that critically constrain imaging quality and compromise the accuracy of spectral reconstruction. To improve interferogram fidelity and obtain precise Raman spectra, this study systematically investigates the primary stray light sources in the optical path and develops targeted suppression strategies. According to Raman scattering principles and system-specific characteristics, we conducted numerical simulations and analytical evaluations of stray light propagation. By implementing optimized optical filtration for incoming stray light and incorporating laser beam shaping/filtering techniques, stray light infiltration into the interferometric system has been effectively mitigated. These advancements have collectively enhanced imaging resolution and elevated the spectral signal-to-noise ratio (SNR). The refined spectral quality significantly counteracts MLA-induced stray light interference, thereby strengthening the analytical capabilities of MLA-enhanced SHRS system (MLA-SHRS) for complex sample detection. This progress is particularly impactful in scenarios requiring high spatial resolution alongside robust stray light rejection, such as multi-component analysis and spatially heterogeneous sample characterization.