(IMAGE) National Institutes of Natural Sciences Caption Reduction in influence of atmospheric pressure (gas) with harmonic interferometer. The interferometer can obtain information (density, etc.) of the medium from the time (phase) difference between two waves. Credit NINS/NIFS Usage Restrictions None License Licensed content 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.