  Progress in high-performance computing demands significant advances in memory
technology. Among novel memory technologies that promise efficient device
operation on a sub-ns timescale, resistance switching between charge ordered
phases of the 1T-TaS$_2$ has shown to be potentially useful for the development
of high-speed, energy efficient non-volatile memory device. While ultrafast
switching was previously reported with optical pulses, determination of the
intrinsic speed limits of actual devices that are triggered by electrical
pulses is technically challenging and hitherto still largely unexplored. A new
optoelectronic laboratory-on-a-chip, designed for measurements of ultrafast
memory switching, enables an accurate measurement of the electrical switching
parameters with 100 fs temporal resolution. A photoconductive response is used
for ultrashort electrical pulse generation, while its propagation along a
coplanar transmission line is detected using electro-optical sampling using a
purpose-grown highly-resistive electro-optic (Cd,Mn)Te crystal substrate. By
combining the transmission line and the 1T-TaS$_2$ device in a single
optoelectronic circuit a non-volatile resistance switching with a single 1.9 ps
electrical pulse is demonstrated, with an extremely small switching energy
density per unit area E$_A$ = 9.4 fJ/$\mu$m$^2$. The experiments demonstrate
ultrafast, energy-efficient circuits utilizing switching between non-volatile
charge-ordered states offers a new technological platform for cryogenic memory
devices.
