Identification and Measurement of Positive and Negative Topological Charges of LG Beams for Medical Care

Abstract

A medical care system’s security, high-capacity information transfer, and communication are all dependent on OAM-based quantum key distribution, namely on the measurement of OAM’s topological charges (TCs). The intensity patterns of interference between the vortex beam and its conjugate beam are analyzed to detect and evaluate positive and negative TCs of Laguerre-Gaussian (LG) vortex beams in a novel manner. An upgraded Mach–Zehnder (M-Z) interferometer is used to establish the order of positive, negative, integer, and half-integer TCs. Deciphering the order of integer TCs and half-integer TCs may be accomplished by measuring the interference bright petals as well as half of the total numbers of bright petals. The integer and half-integer TCs (VPP) may be modulated by the use of light path rotational with a vortex stage plate. Using the interferometer as mentioned earlier, the positive and negative of integer and half-integer TCs are acquired. Quantitatively, the order and sign of integer and half-integer TCs are measured in this manner. And this method is straightforward and less susceptible to the influence of parasitic interference. This can provide comprehensive security protection for the medical monitoring system, better reduce medical risks and protect patient privacy.