A testing apparatus for dynamic characterization of a sample of a material under test. A terahertz (THz) time-domain spectroscopy system is configured and arranged to generate and detect terahertz waves to interrogate the sample. A shock wave loading system is configured and arranged to produce a shock wave in the sample concurrently with said THz spectroscopy device interrogating the sample. The sample undergoes changes in an index of refraction in response to the produced ultrafast shock wave in the sample that are detected by the terahertz spectroscopy system.