Highly stable dual-galvanometer mirror remote spatial offset Raman spectroscopy detection method.

Due to differences in the molecular chain orientation of anisotropic packaging materials, the Raman scattering intensity of their surface layers exhibits significant directional dependence, which hinders the effective extraction of signals from deeper layers. Traditional remote SORS systems typically use single-point, fixed-position detection, making it difficult to ensure reliable detection of materials deep within anisotropic packaging materials. Therefore, we propose a dual-galvanometer mirror ring scanning remote SORS detection method, which uses ring scanning for spectral sampling and signal accumulation to reduce the signal variations caused by molecular-chain orientation and improve the stability of deep-layer detection. Experiments at a detection distance of 5 m showed that the surface PTFE interference signal was reduced by 42% compared with conventional detection methods. In the multi-point detection of actual HDPE samples, the relative standard deviation of the target-to-packaging signal ratio was reduced from 70.61% in traditional single-point detection methods to 2.9%, thereby improving the identification and detection stability. Under the current experimental conditions, it is expected to provide a technical solution for non-invasive remote detection of deep substances inside anisotropic packaging.