Generation of an ultra-short electrical pulse with width shorter than the excitation laser

Abstract

We demonstrate experimentally a rare phenomenon that the width of an electrical response is shorter than that of the excitation laser. In this work, generation of an ultrashort electrical pulse is by a semi-insulating GaAs photoconductive semiconductor switch (PCSS) and the generated electrical pulse width is shorter than that of the excitation laser from diode laser. When the pulse width and energy of the excitation laser are fixed at 25.7 ns and 1.6 μJ respectively, the width of the generated electrical pulse width by 3-mm-gap GaAs PCSS at the bias voltage of 9 kV is only 7.3 ns. The model of photon-activated charge domain (PACD) is used to explain the peculiar phenomenon in our experiment. The ultrashort electrical pulse width is mainly relevant to the time interval of PACD from occurrence to disappearance in the mode. The shorter the time interval is, the narrower the electrical pulse width will become. In more general terms, our result suggests that in nonlinear regime a response signal can have a much short width than the excitation pulses. The result clearly indicates that generating ultrashort electrical pulses can be achieved without the need of ultrashort lasers.

Investigation on the surface flashover of high gain SI‐GaAs PCSS

“… The domain forming and the distortion of fieldWhen the switches work at the linear mode, we think that the field is uniform and the carriers transport uniformly in the bulk of switches. But, when the switches work at the high‐gain mode, because of the negative differential resistance effect, the PACD is formed in the switches . The field at the head of the domain is far larger than that at other regions, even larger than the avalanche threshold electric field.…”

998 Multiplication Rate of GaAs Avalanche Semiconductor Switch Triggered by 0.567 nJ

“…When the electric field is lower than the avalanche threshold electric field (7.5 kV/cm) [10], this electric field strength is the minimum electric field threshold required to enter avalanche mode. Below this electric field strength, the GaAs PCSS works in a linear mode, each photon generates a pair of electron-hole pairs, and the conductivity of the conducting material has a linear relationship with the trigger optical energy.…”

“…When the bias electric field was stronger than the threshold electric field of the avalanche mode, the GaAs PCSS operated in the avalanche mode. The photon-activated carriers formed a photonactivated charge domain (PACD) in the GaAs PCSS [10]. The PACD was composed of the excess electron regions and electron depletion regions, as shown in Fig 5(a).…”

1.6-kV 1.5-kA GaAs Avalanche Semiconductor Switch Triggered by 4 μJ Laser Diode

“…Moreover, the oscillation becomes stronger as well. When the electric field bias is higher than the nonlinear threshold electric field (7.5 kV/cm) [16], the PCSS operates in the nonlinear mode. When the LD triggers the PCSS, the photon-activated carriers form a PACD in the PCSS and this highly localized electric field in the PACD satisfies the avalanche breakdown condition.…”