Trapping A Rainbow (image) Lehigh University Caption Microscope images of graded gratings with different gradients. In this measurement, three filters are employed: (a) A multi-band filter (Semrock, transmission bands centered at 542nm and 639nm). (b) A green filter centered at 546nm (bandwidth 6nm). (c) A red filter centered at 655nm (bandwidth 12nm). Credit Filbert J. Bartoli, Lehigh University Usage Restrictions Please credit investigator and University 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.