In summary, a chirped woodpile PhC, whose layer-to-layer distances are gradually decreased along the propagation direction, has been numerically and experimentally demonstrated to slow down and finally to trap and enhance different frequency components at different spatial positions. It has been argued that the Fabry-Perot interferences occurring between the turning points and the entrance of the structure together with the adiabatic slowing mechanism can lead to intensity enhancements close to two orders of magnitude. An experimental realization at the microwave regime verified the operation principle, and we further note that the proposed structure is also feasible for current nanofabrication technologies, such as electron-beam lithography46 or direct laser writing techniques47, 48, due to its simple layer-by-layer architecture and its robustness against fabrication disorders34, 35. Furthermore we showed that the propagation losses can be suppressed, owing to the 3D periodicity of the structure. Such a phenomenon could be exploited to realize nonlinear optical devices, broadband photon harvesting systems, wavelength division multiplexing devices and optical buffers. We should note however, that the light enhancement phenomenon in the proposed configuration should not be considered as a permanent storage of a ‘trapped rainbow’7, but rather a temporary localization, due to the finite trapping time caused by the reflection at the turning points25, 49. It should be also noted that although high group indices up to 110 have been measured, a zero group velocity near the localization region could not be obtained due to additional out-of-plane losses and experimental limitations.