Smartphone Optical Fiber Spectrometers

Abstract

The advancement of smartphone instrumentation continues to penetrate further in spectroscopy by developing devices that are capable to measure sample in an arbitrary shape and place. In particular, to measure spectra from solids or surfaces, a flexible fiber bundle probe is integrated onto the designed smartphone spectrometer platform demonstrating an optical fiber smartphone spectrometer. The fiber bundle allows light collection in both ways—from source to sample and sample to detector. A customized Android app is written to process spectra on the smartphone platform; the data can be shared or analyzed remotely via the Internet. A step-by-step calibration process was used where specific correction factors are applied to produce an accurate spectral response [98]. The instrument has been demonstrated by measuring the visible absorption spectra of apples during their storage time. The optical fiber smartphone spectrometer was customized further by integrating an array of UV LEDs for fluorescence measurements while powering the entire system using the smartphone’s battery, retaining the self-powered credential of the device. Using the instrument, visible fluorescence spectra were measured to characterize vegetable oils.