Dual-mode optical microscope based on single-pixel imaging

We demonstrate an inverted microscope that can image specimens in both reflection and transmission modes simultaneously with a single light source. The microscope utilizes a digital micromirror device (DMD) for patterned illumination altogether with two single-pixel photosensors for efficient light detection. The system, a scan-less device with no moving parts, works by sequential projection of a set of binary intensity patterns onto the sample that are codified onto a modified commercial DMD. Data to be displayed are geometrically transformed before written into a memory cell to cancel optical artifacts coming from the diamond-like shaped structure of the micromirror array. The 24-bit color depth of the display is fully exploited to increase the frame rate by a factor of 24, which makes the technique practicable for real samples. Our commercial DMD-based LED-illumination is cost effective and can be easily coupled as an add-on module for already existing inverted microscopes. The reflection and transmission information provided by our dual microscope complement each other and can be useful for imaging non-uniform samples and to prevent self-shadowing effects.This work was supported by MINECO through projects FIS2013-40666-P, the Generalitat Valenciana PROMETEO/2012/021, ISIC/2012/013, and by the Universitat Jaume I P1-1B2012-55. A.D. Rodríguez acknowledges grant PREDOC/2012/41 from Universitat Jaume I. Thanks also to Dr. Tatiana Pina and Dr. Josep Jaques from Universitat Jaume I for providing us the biological samples