Underwater laser-guided discharge using lens-initiated optical filaments

A method for producing a laser-guided underwater electrical discharge, comprising:

• at time t1, firing a laser pulse having a power P greater than a critical power Pcrit through one or more focusing lenses and past a first electrode in a body of water,
• the laser pulse and the focusing lenses being configured to cause the laser pulse to generate a lens-initiated optical filament at a desired location in the water, the optical filament defining a desired electrical discharge path in the water, the power P of the laser pulse further being configured to cause the optical filament to heat a water channel coincident with the optical filament and to cause the water channel to vaporize and expand at time t2>t1 to form a vapor channel around the optical filament, the vapor channel having a greater conductivity than the water surrounding the vapor channel;
• and
• using an external power supply connected to the first electrode, producing a driving electric field which generates an electrical discharge at time t3>t2;
• wherein the optical filament is configured to guide the electrical discharge through the vapor channel along the desired electrical discharge path defined by the optical filament.

A method for producing a laser-guided underwater electrical discharge, comprising:

• at time t1, firing a first laser pulse having a power P1 greater than a critical power Pcrit (liquid water) through one or more focusing lenses and past a first electrode in a body of water,
• the power P1 and the lens being configured to cause the first laser pulse to generate a first lens-initiated optical filament at a desired location in the water, the power P1 of the first laser pulse being further configured to cause the optical filament to heat a liquid water channel coincident with the first optical filament and to cause the liquid water channel to vaporize and expand at time t2>t1 to form a water vapor channel surrounding the first optical filament;
• at time t3>t2, firing a second laser pulse having a power P2 greater than a critical power level Pcrit (water vapor) through the water vapor channel, the power P2 and a focusing of the second laser pulse being configured to cause the second laser pulse to generate a second optical filament defining a desired electrical discharge path within the water vapor channel, wherein the second optical filament forms a laser-ionized conductive channel through the water vapor channel along the desired electrical discharge path;
• and
• using an external power supply connected to the first electrode, producing a driving electric field which generates an electrical discharge at time t4>t3;
• wherein the second optical filament is configured to guide the electrical discharge through the laser-ionized channel along the desired electrical discharge path defined by the second optical filament.

A method for producing a laser-guided electrical discharge in a liquid, comprising:

• at time t1, firing a laser pulse having a power P greater than a critical power Pcrit through one or more focusing lenses and past a first electrode in a liquid,
• the laser pulse and the lens being configured to cause the laser pulse to generate a lens-initiated optical filament defining a desired electrical discharge path at a desired location in the liquid, the optical filament forming a laser-ionized channel through the liquid along the desired electrical discharge path, the laser-ionized channel having a greater conductivity than the surrounding liquid;
• and
• using external power supply connected to the first electrode, producing a driving electric field which generates an electrical discharge at time t2>t1;
• wherein the optical filament is configured to guide the electrical discharge through the laser-ionized channel along the desired electrical discharge path defined by the optical filament.

A method for producing a laser-guided electrical discharge in a liquid, comprising:

• at time t1, firing a laser pulse a power P greater than a critical power level Pcrit through one or more focusing lenses and past a first electrode in a liquid,
• the laser pulse and the lens being configured to cause the laser pulse to generate a lens-initiated optical filament defining a desired electrical discharge path at a desired location in the liquid, the power P of the laser pulse further being configured to cause the optical filament to heat a liquid column coincident with the optical filament, and to cause the liquid column to vaporize and expand at time t2>t1 to form a vapor channel around the optical filament, the vapor channel having a higher conductivity than the surrounding liquid;
• and
• using an external power supply connected to the electrode, producing a driving electric field which generates an electrical discharge at time t3>t2;
• wherein the optical filament is configured to guide the electrical discharge through the vapor channel along the desired electrical discharge path defined by the optical filament.