graded index glass pyramid fabrication (IMAGE) Stanford University Caption Different stages of the graded index glass pyramid fabrication: when in optical contact with a solar cell, the pyramid at the final step (bottom right corner) absorbs and concentrates most of the incident light and appears dark. Credit Image credit: Nina Vaidya Usage Restrictions Only for use in publicizing this research. License Original 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.