Optical beaming of electrical discharges

Abstract

Igniting and guiding electrical discharges to desired targets in the ambient atmosphere have been a subject of intense research efforts for decades. Ability to control discharge and its propagation can pave the way to a broad range of applications from nanofabrication and plasma medicine to monitoring of atmospheric pollution and, ultimately, taming lightning strikes. Numerous experiments utilizing powerful pulsed lasers with peak-intensity above air photoionization and photo-dissociation have demonstrated excitation and confinement of plasma tracks in the wakes of laser field. Here, we propose and demonstrate an efficient approach for triggering, trapping and guiding electrical discharges in air. It is based on the use of a low-power continuous-wave vortex beam that traps and transports light-absorbing particles in mid-air. We demonstrate a 30% decrease in discharge threshold mediated by optically trapped graphene microparticles with the use of a laser beam of a few hundred milliwatts of power. Our demonstration may pave the way to guiding electrical discharges along arbitrary paths.

Determining the spatial distribution of laser-induced plasma by laser-induced voltaic measurement

“…Besides, as the laser energy increases from 24.5 mJ to 41 mJ, the bright spot extends in the direction of laser illumination, with the length increases from 5 mm to about 1 cm. The breakdown of air by a focusing laser to generate plasma conforms to the theory of Townsend discharge, which is described as three stages [34][35][36][37]. For the charged particles in atmosphere, they move around in space irregularly in absence of an external field.…”

Individual Micron-Sized Aerosol Qualitative Analysis-Combined Raman Spectroscopy and Laser-Induced Breakdown Spectroscopy by Optical Trapping in Air

“…Meanwhile, it can be inferred that, under the action of optical tweezers, the pulsed laser will ablate some or all of the trapped particles (depending on the particle size) within 7 ns. , Due to the low breakdown threshold of the particles in comparison to air, when the laser pulse arrives (Figure B), the particles are dissociated at the rising edge of the pulse to generate a particle plasma . The air is dissociated to produce an air plasma as the laser pulse energy rises to the air’s breakdown threshold.…”

“…36,37 Due to the low breakdown threshold of the particles in comparison to air, when the laser pulse arrives (Figure 2B), the particles are dissociated at the rising edge of the pulse to generate a particle plasma. 38 The air is dissociated to produce an air plasma as the laser pulse energy rises to the air's breakdown threshold. Air absorbs more energy to create longer-lasting air plasmas because its energy absorption crosssection is much larger than that of particles (air volume is significantly greater than particle volume at the focus point).…”

Tailored mesoscopic plasma accelerates electrons exploiting parametric instability

“…In this work, we present both experimental and simulation data where strong, TPD emission of large bandwidth (in comparison to that of the pump laser pulse) is observed for 30 fs, 3 mJ laser pulses interacting with mass limited targets, in the non-relativistic intensity regime ∼10 16 W cm −2 and assists electron acceleration to MeV energies. In the presence of a pre-pulse, the main laser pulse interaction with an isolated, size-limited solid micro-particle surrounded by a low-density gas (termed as micro-dust target in this paper) differs from that of plasma studies with solid targets [48,49], high-density gas targets [10,11] or microparticles in discharge tubes [50,51]. Here, a low-density plasma region where the plasma waves can be generated, grown, and driven to a localized critical density (n cr ) surface provides very suitable conditions for very hot electron generation.…”