Inexpensive LED-Based Optical Coating Sensor

Optical coatings are widespread in everyday life, from camera lenses and glasses, to complex optics experiments. Thus, a simple, reliable sensor that can quickly and inexpensively analyze optical coatings is a valuable laboratory tool. Such a device can help identify optical coatings and characterize the transmission spectra of optical components used in an experiment. We present the design and characterization of a LED-based spectrophotometer and demonstrate its ability to identify different optical coatings. Our approach uses ten LEDs that cover a spectrum from 365 nm to 1000 nm. The optical coating sensor is automated, portable, inexpensive, user-friendly, and simple to build.