Differential single-pixel camera enabling low-cost microscopy in near-infrared spectral region

The optical microscope for wavelengths above 1100 nm is a very important tool for characterizing the microstructure of a broad range of samples. The availability of the technique is, however, limited because special detectors with temperature stabilization, which are costly, must be used. We present the construction of a low-cost near-infrared microscope (800-1700 nm) based on the principles of compressed sensing. The presented setup is very simple and robust. It requires no temperature stabilization and can be used under standard laboratory conditions. We demonstrate that such a microscope, which uses a simple pair of balanced photodiodes as a detector, can acquire microscopic images of the sample that are comparable with those acquired by a standard microscope. Owing to its simplicity, the presented setup can provide access to infrared transmission microscopy and to a broad range of laboratories.