Optics and Photonics February 12, 2019
To overcome the bulky spatial light modulators and other optical components for ghost imaging, researchers in Japan used a phased array of 128 tiny phase shifters packed onto a chip with a 4×4-mm footprint. In the chip setup, input light from a 1550-nm laser, coupled into the array via a lensed fiber, is split into 128 waveguides and piped into the phase-shifting elements of the array. Each individual phase shifter can be electrically controlled, allowing rapid creation of a series of random speckled patterns at refresh rates faster than the few-frame-per-second. The random pattern is both sent to a computer and shone on the object to be imaged. The ghost imaging happens when the computer reconstructs the object image from multiple correlated random patterns, weighted by the intensity signal from the photodiode. According to the researchers the setup, if it can be scaled up commercially, could find applications in low-cost, fast imaging systems for lidar, smartphone-based imaging and more…read more. Open Access TECHNICAL ARTICLE
Credit: Takuo Tanemura, University of Tokyo