Direct Measurement of Complex Wave Field by Exposure Lens

Based on transformation optics, the recently proposed exposure lens provides a simple and effective tool to manipulate and detect complex wave signals. This GRIN lens can expose the inner 1D space of a wave field inside a beam volume to the surface of the propagation medium and extend the space from 1D to 2D, allowing the corresponding field distribution to be detected directly and more subtly. In this paper, two kinds of exposure lens are reviewed. Using both types of lenses to detect chirp signals expands the modulation frequency detection spectrum, constituting a complete kit for chirpiness detection with potential application to signal processing. Furthermore, the quality of radial polarized cylindrical vector beam can be detailed inspected by exposure lens. The detection of the internal states and quality of cylindrical vector beam is useful to their development and applications.