Exposing and extending the interior waves field by transformation materials

Based on transformation optics, a strategy is proposed to expose the inner one-dimensional (1D) space of a wave field inside a beam volume to the surface of the propagation medium and extend the space from 1D to two-dimensional, allowing the corresponding field distribution to be detected directly and more subtly, which is important in optical signal processing. The method is applied to the quadratic graded index lens to construct a new graded index lens, and its enhanced chirpiness detection ability is demonstrated by numerical simulation.