Resumen de Visualizing Light Beams Diffracted by a CMOS Sensor with a Fluorescent Dye
Complementary metal–oxide–semiconductor (CMOS) sensor chips, made by an advanced manufacturing process, can be used for demonstrating two-dimensional diffraction since many pixel units are arrayed on the chip periodically. Coincidentally, the CMOS sensors in discarded cameras or smartphones have small pixel sizes, close to visible light wavelength. Compared with the already packaged chips with periodic structures, the CMOS periodic surface is protected by one or two transparent glass sheets (filters). These make the CMOS sensors in discarded cameras good teaching tools, to be used as a reflection grating. J. Barreiro et al. made diffraction experiments on a series of electronic components (charge-coupled device, liquid crystal display, etc.) with a simple and ingenious method.1 Ekkens used the erasable programmable read-only memory (EPROM) chip as a reflection grating and observed the interesting distribution of diffraction patterns.2 Rabosky et al. modified the reflected diffraction experiments to include a non-normal incidence condition.3 Testing the spacing of the reflected diffraction pattern has been proven to be a sufficiently accurate method. Transparent fluorescent material can display the propagation path of excitation light, which inspired us to use fluorescent dyes in transparent solvent to visually demonstrate the diffracted light and angles. Here we measured the grating diffraction constant d of the CMOS sensor (Canon 550D) with two methods and used a rhodamine B solution to demonstrate the distribution of the diffracted light. Based on those two methods, teaching aids are prepared to demonstrate the shape of the diffraction light path.
