Harnessing abruptly auto-defocusing beam to enhance the Raman signal in aqueous humor:A simulation analysis

Raman aqueous humor detection provides a non-invasive, molecular-level approach for ingredient analysis within aqueous humor. However, current Raman aqueous humor applications are facing low signal-to-noise levels due to the trade-off between laser power and laser safety. In order to increase Raman signal while guaranteeing laser safety, in the research, we propose to use the abruptly auto-defocusing (AADF) beam as the illumination source for Raman aqueous humor spectroscopy. The ray-tracing sketch together with the propagation simulation of AADF shows its evolution within the aqueous humor. The intensity distributions are analyzed with and without the impact of corneal refraction. Results show that the efficiency of AADF is higher than the conventional focused Gaussian beam (FGB) method with center blocked. The peak value of the Raman signal intensity acquired using the AADF method is about 6 times larger than that of an FGB.