Negative group velocity pulse tunneling through a coaxial photonic crystal

An easily configurable experimental system is described in which negative group velocity tunneling of electrical pulses can be studied. Negative group velocity corresponds to the case in which the peak of a tunneled pulse exits before the peak of the incident pulse has entered the sample. In the experiments outlined herein, the tunneling occurs through the forbidden transmission region of a quarter-wavelength interference filter created from alternating segments of two different impedance coaxial cables. The equipment used for these experiments consists of two function generators and an oscilloscope, items typically found in most science departments.