|  | 
         
          | Description: 
             The top image shows a pair 
            of crystals bending a laser beam at a negative angle, and the bottom 
            image shows the same pair bending a beam at a positive angle. The 
            blue and green lines are laser beams. The red line is perpendicular 
            to the crystal seam. |   
          | Source: 
             National Renewable Energy Laboratory |   
          | Story:  Crystal 
            bends light back TRN November 5/12, 2003
 |   
          | TRN Categories: 
             Optical Computing, Optoelectronics 
            and Photonics; Materials Science and Engineering; Physics |   
          | Form: 
             Still |  |