Images of the Aperture Filter (image) The Optical Society Caption These are near-infrared (left) and visible (right) images of the aperture filter, used in the new dual-mode imager. Only the central region of the filter can transmit visible light, while the outer portion can only transmit the near-infrared light used for fluorescent imaging. Credit Optics Letters Usage Restrictions Include caption & credit Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.