Two-dimensional materials, with their atomic-scale thickness and novel physical properties, represent promising candidates for designing highly integrated artificial intelligence chips. However, their atomic thickness, while advantageous for integration, results in weak light absorption, resulting in a limited photoresponse and hindering their use in artificial vision devices. To address this issue, we propose an optical synaptic device based on an R6G/InSe hybrid structure. In this hybrid device, R6G serves as a photosensitive layer, effectively enhancing the photoresponse of the 2D InSe sensing layer, with this effect attributed to charge transfer between the dye molecules and the channel material. We employed a non-destructive spectroscopic technique, surface-enhanced Raman spectroscopy (SERS), in conjunction with electrical testing, to demonstrate the charge transfer mechanism. Furthermore, we introduced an oxide layer on the InSe surface through oxygen plasma treatment. The presence of the oxide layer hindered the charge transfer process, providing further evidence for the charge transfer mechanism. The proposed hybrid-structure device exhibits outstanding optical synaptic performance, facilitating image denoising preprocessing similar to that achieved by artificial neural network functions. We realized encryption and decryption of image information using artificially introduced noise backgrounds and further proposed a design concept for an anti-counterfeiting chip by designing a hybrid device array. In summary, the design of the R6G/InSe hybrid-structure device we propose offers a reference solution for enhancing the optical response of 2D material devices. Additionally, our encryption and anti-counterfeiting applications present new directions for the use of 2D materials in optoelectronic devices.