FIG 1 (IMAGE) Compuscript Ltd Caption Fig. 1. (a) Planar LC structure of a general PBOE. (b) Chromatic aberration in a broadband PBL. (c) LC structure for a multi-twist PBOE. (d) Experimental result of a broadband PBL. Credit OEA Usage Restrictions Credit must be given to the creator. License CC BY 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.