Sweeping Laser Schematic (IMAGE) University of California - Berkeley Caption This self-sweeping laser couples an optical field with the mechanical motion of a high-contrast grating (HCG) mirror. The HCG mirror is supported by mechanical springs connected to layers of semiconductor material. The red layer represents the laser's gain (for light amplification), and the blue layers form the system's second mirror. The force of the light causes the top mirror to vibrate at high speed. The vibration allows the laser to automatically change color as it scans. Credit Schematic by Weijian Yang Usage Restrictions All rights reserved. Editorial use only. Commercial use prohibited. 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.