A novel optical design by ultraviolet visible-near infrared absorption spectroscopy with dual elliptical reflectors for the detection of Mycobacterium ulcerans

In this research, an optical design model of an elliptical dual reflector working in the near-ultraviolet (UV)-Visible (UV-VIS) region for the detection of Mycobacterium ulcerans is presented. This approach aims at developing an original, portable, non-invasive and usable on the field diagnostic device. The Henyey-Greenstein scattering skin model is used in the simulation model to calculate the light scattering phenomena. Based on a virtual skin model, the dual elliptical reflector system can focus the light from LEDs into the depths of human skin and enhance the collection of backscattered light. Based on this assumption, the normalized light collection efficiency (LCE) of the LED and photodiode can be kept between 0.97 and 1, respectively for a sensor displacement between full contact and a distance of 0.2 mm parallel to the object’s normal. With a chip tilt error smaller than 5°, the normalized light collection efficiency (LCE) is at least 0.95.