Speckle-free, near-infrared portable confocal microscope

We have developed a portable confocal microscope (PCM) that uses an inexpensive near-infrared (NIR) LED as the light source. Use of the spatially incoherent light source significantly reduced the speckle contrast. The PCM device was manufactured at the material cost of approximately $5,000 and weighed only 1 kg. Lateral and axial resolutions were measured as 1.6 µm and 6.0 µm, respectively. Preliminary in vivo skin imaging experiment results showed that the PCM device could visualize characteristic cellular features of human skin extending from the stratum corneum to the superficial dermis. Dynamic imaging of blood flow in vivo was also demonstrated. The capability to visualize cellular features up to the superficial dermis are expected to facilitate evaluation and clinical adoption of this low-cost diagnostic imaging tool.