The Research On The Optical Model Of Human Photoreceptors

There are two kinds of photoreceptor cells in human retina, which are called cone and rod cell respectively. The cones and rods are responsible for photopic vision and scotopic vision respectively. The characteristics of optical waveguide of human photoreceptors play important roles in vision and nearly 80% of the information acquired from the outside world is from vision in human life. Many researches have been done on the electrical and physiology properties of photoreceptor cells, but little work has been done on the optical waveguide properties of them.The optical properties(such as mode field diameter, coupling loss, working mode and so on) of human cones and rods have been studied using optical waveguide theory in this article and some new golden ratio points in vision have been found. The results of the study are as follows: The values of mode field diameter of outer segments of cones are nearly the smallest at their geometrical diameter, which is benefit to reduce optical crosstalk between neighboring cones. The outer segment of rod cell works in multi-mode to improve sensitivity. The mode field diameters of some parts of cone cells are insensitive to the tiny alter of their diameters, which is benefit to make cones stable. The ellipsoid of cone cell has the function of reducing coupling loss between the myoid and outer segment, which is benefit to improve the sensitivity of vision. Any attempt to substitute the function of cone ellipsoid will suffer reduce of other performances. And the normalized frequency and the lateral dimension of some parts of rods have been imitated to improve the important performances, such as working temperature, frequency, dark count rate(DCR), after-pulse probability(AP) and photon detection efficiency(PDE) of the single photon avalanche photodiode(SPAD) used at present.