Compact Spectrometer Based on a Frosted Glass

We demonstrate a spectrometer based on multiple interference and scattering in an ordinary frosted glass featuring random structures. The probe signal disperses through the frosted glass generating wavelength-dependent speckle patterns, which are detected by a charge coupled device chip and used to reconstruct the input spectrum after calibration. We consider an underdetermined system of linear equations as a model for signal spectrum estimation. Smoothing regularization algorithm is designed for solving the system of equations. Experimental results show that the reconstruction range of the spectrometer at least includes the entire visible band and some part of the ultraviolet band. In comparison with conventional miniature spectrometers, the frosted glass spectrometer consequently has the merits of static measurement, low cost, small size, high throughput, and wide spectral range, which may find applications in a wide range of applications.