Electric Field Vector Measurements Via Nanosecond Electric Field Induced Second Harmonic GenerationOptics Letters
- Tat Loon Chng, Maya Naphade, Benjamin Goldberg, Igor Adamovich, and Svetlana Starikovskaya
- received 08/15/2019; accepted 10/19/2019; posted 10/21/2019; Doc. ID 374833
- Abstract: Electric field induced second harmonic generation, or E-FISH, has received renewed interest as a non-intrusive tool for probing electric fields in gas discharges and plasmas using ultrashort laser pulses. An important contribution of this work lies in establishing that the E-FISH method works effectively in the nanosecond regime, yielding field sensitivities of about a kV/cm at atmospheric pressure from a 16 ns pulse. This is expected to broaden its applicability within the plasma community, given the wider access to conventional nanosecond laser sources. A Pockels-cell-based pulse-slicing scheme, which may be readily integrated with such nanosecond laser systems, is shown to be a complementary and cost-effective option for improving the time resolution of the electric field measurement. Using this scheme, a time resolution of ~3 ns is achieved, without any detriment to the signal sensitivity. This could prove invaluable for non-equilibrium plasma applications, where time resolution of a few nanoseconds or less is often critical. Finally, we take advantage of the field vector sensitivity of the E-FISH signal to demonstrate simultaneous measurements of both the horizontal and vertical components of the electric field.