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We report the first sub-picosecond shock-waves ever generated and measured by electronic circuits. We have used these circuits with integrated antennas to generate freely-propagating THz radiation. The circuits are monolithic nonlinear transmission lines fabricated on GaAs and operating at T = 77 K. Nonlinear transmission lines (NLTL's) have been used by several researchers for generating electronic shock-waves with picosecond transition times by compressing the wavefront of a microwave power source.1 While the literature reflects continual decreases in these transition times, as measured both by diode sampling bridges and by electro-optic sampling, the fastest reported 10%-90% fall time thus far has been 1.4 ps, with a -5 V amplitude.2 However, generating and measuring a sub-picosecond transition with an all-electronic device has been an elusive goal because a fundamental limitation has been the NLTL diode series resistance. By immersing a packaged NLTL into liquid nitrogen, we were able to lower this resistance significantly, thereby producing voltage shock-waves with 880 fs fall times and 3.5 V amplitudes, as measured by an on-chip diode sampling bridge. We have used these circuits with integrated magnetic dipole (slot) antennas to generate freely propagating THz radiation, and we have observed measurable radiation beyond 3 THz.
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