US-12620767-B1 - Defensive laser amplification system

US12620767B1US 12620767 B1US12620767 B1US 12620767B1US-12620767-B1

Abstract

A counter high-energy laser system directs high-intensity laser radiation back to a threat laser in the form of an ultra-short optical pulse (USP). The retro-directed USP induces permanent internal optical damage in the threat laser, thus disabling the threat by exploiting the very high optical gain at the source of an incoming laser thereby causing an injected pulse to grow exponentially in energy and peak power within the threat laser optical train until it reaches a damaging threshold. The existing optical energy from the threat laser system and stored in the laser beam from threat system is exploited thereby enabling the size, weight, and power of the counter laser system to be significantly reduced. The wavelength of the counter pulse is automatically matched to the threat.

Inventors

Stephen William McCahon
Alan Kost
Gregory J. Quarles

Assignees

APPLIED ENERGETICS, INC.

Dates

Publication Date: 20260505
Application Date: 20220805

Claims (20)

1 . A defensive laser amplification system, comprising; collection optics configured to receive laser energy from a threat; a threat conditioning module, coupled to the collection optics, configured to condition the laser energy from the threat; an oscillator configured to form an ultra-short supercontinuum pulse; an energy transfer sub-system, coupled to the threat conditioning module and the oscillator, configured to receive the conditioned laser energy and the ultra-short supercontinuum pulse and configured to convert the conditioned laser energy to a high-energy ultra-short-pulse; and transmission optics coupled to the energy transfer sub-system and configured to transmit the high-energy ultra-short-pulse linked to the threat.
2 . The defensive laser amplification system according to claim 1 , further comprising an optical amplifier to increase the energy and peak optical power of an ultra-short counter pulse.
3 . The defensive laser amplification system according to claim 1 , further comprising a Raman amplifier to increase the energy and peak optical power of an ultra-short counter pulse.
4 . The defensive laser amplification system according to claim 1 , wherein the resonating cavity in the energy transfer sub-system is an amplifying fiber.
5 . The defensive laser amplification system according to claim 4 , wherein the amplifying fiber is a solid-core optical fiber.
6 . The defensive laser amplification system according to claim 4 , wherein the amplifying fiber is a photonic crystal fiber.
7 . The defensive laser amplification system according to claim 1 , wherein the oscillator employs a mode-locked laser.
8 . The defensive laser amplification system according to claim 7 , wherein a spectrum of an ultra-short pulse from the mode-locked laser is expanded by a combination of nonlinear optical effects.
9 . The defensive laser amplification system according to claim 1 , wherein the high-energy ultra-short-pulse has a wavelength linked to the conditioned laser energy.
10 . The defensive laser amplification system according to claim 1 , wherein a medium for the energy transfer sub-system is configured to have a large optical nonlinearity.
11 . The defensive laser amplification system according to claim 1 , wherein the laser energy is a continuous wave laser threat.
12 . The defensive laser amplification system according to claim 11 , wherein the threat conditioning module is configured to identify a wavelength of the continuous wave laser threat.
13 . A method for transmitting a defensive laser, comprising: receiving, by collection optics, laser energy from a threat; filtering the laser energy from the threat; forming, by an oscillator, an ultra-short supercontinuum pulse receiving the conditioned laser energy by an energy transfer sub-system; injecting into a resonating cavity of the energy transfer sub-system, the ultra-short supercontinuum pulse thereby converting a portion of the a ultra-short supercontinuum pulse to a high-peak power ultra-short-pulse and transmitting by transmission optics the high-peak power ultra-short-pulse to the threat.
14 . The method for transmitting a defensive laser according to claim 13 , wherein the laser energy is a continuous wave laser threat.
15 . The method for transmitting a defensive laser according to claim 13 , further comprising identifying a wavelength of the continuous wave laser threat.
16 . The method for transmitting a defensive laser according to claim 15 , wherein the high-peak power ultra-short-pulse has a wavelength linked to the threat.
17 . The method for transmitting a defensive laser according to claim 13 , further comprising configuring a Raman amplifier for a spectral portion of the ultra-broadband, supercontinuum pulse.
18 . The method for transmitting a defensive laser according to claim 17 , further comprising forming an amplified ultra-short-pulse by Stimulated Raman Amplification in the Raman amplifier.
19 . The method for transmitting a defensive laser according to claim 18 , further comprising linking the amplified ultra-broadband, supercontinuum pulse to a wavelength of the threat.
20 . The method for transmitting a defensive laser according to claim 13 , wherein the energy transfer sub-system employs an amplifying fiber.

Description

RELATED APPLICATION The present application relates to and claims the benefit of priority to U.S. Provisional Patent Application No. 63/260,028 filed 6 Aug. 2021 which is hereby incorporated by reference in its entirety for all purposes as if fully set forth herein. BACKGROUND OF THE INVENTION Field of the Invention Embodiments of the present invention relate, in general, to ultra-short pulse laser energy and more particularly to an automated high energy laser countermeasure using an ultra-short pulse laser. Relevant Background A LASER, or Light Amplification by Stimulated Emission of Radiation, is a high-power light harnessed to create a narrow directional beam. At its most basic levels a laser includes a gain medium in an optical cavity. The cavity is defined, in most instances, by a pair of mirrors at either end that reflect light within the cavity. An energy source or pumping energy in the form of photon or electrical energy completes the basic component list. The gain medium is a set of atoms, molecules, or ions in gaseous, solid, or liquid state that acts to amplify the light. A state in which the number of atoms in the upper energy level is greater than the atoms in the lower energy, or inversion, must exist to form a stimulated emission. An optical pumping light is often used to create the necessary inversion for a laser. A gain medium absorbs the light from a source promoting a portion of the atom population from their ground state to a higher energy state. A material continuously exposed to a pumping light forms a continuous wave while a pulsed wave is formed using flashes. One known class of amplifying pumps are known as regenerative amplifiers. In such an amplifier light passes multiple times through a single gain medium, or plural gain media, to efficiently extract a gain. In a regenerative amplifier, an optical path is defined in which an input pulse or signal makes several passes before being directed out as an amplified signal. Laser pulses with ultrashort pulse durations in the picosecond or femtosecond ranges can be created using this technique. Multiple passes through the gain medium, such as a solid-state medium, are achieved by placing the gain medium in an optical cavity or resonator, together with an optical switch that may be formed by an electro-optic modulator. Laser light can also be amplified by Raman amplification. Raman amplification is the absorption of photons from a pumped signal to a seed signal that are then immediately re-emitted as lower-frequency laser-light photons (“Stokes” photons) by a process called stimulated Raman scattering. The difference between the two photon energies, the pump signal, and the seed signal, is fixed and corresponds to a vibrational frequency of the gain medium. Typically, a population inversion is first created forming a laser emission, or the pumped laser signal. The emission is thereafter amplified via a Raman amplifier. In the current state of the art the Raman amplifier is outside of the optical cavity and not all the energy of the pumped laser signal is transferred to the seed signal. While the seed signal is amplified a degree of inefficiency exists, leaving a residual pumped laser signal. That is, there remains energy in the pumped laser signal that is unused and normally discarded. Continuous Wave (CW) High Energy Laser Systems (HELS) are being developed and deployed by numerous countries. Such systems direct CW high energy lasers to sensitive optics, sensors, and the like to disrupt or destroy the device. CW HELS are a direct threat to satellites and their payloads including sensitive Electro-Optics (EO), Radio Frequency (RF) sensors, and physical structures. Current defense systems to a high energy laser system are either non-effective or nonexistent A CW laser refers to the fact that the light output intensity (energy) is constant over time and characterized by the amount of power it generates in Watts (W). An example of a CW laser is the laser pointer which emits a continuous beam of low power visible light. However, CW lasers in the range of 10 kW to >100 KW pose a serious threat. To appreciate the scope of the threat, recall the amount of energy in Joules (J) over time is expressed as Watts (W), where 1 W=1 J/s. As an example, consider a laser being used to heat water. A calorie is defined as the energy (J) to raise the temperature of 1 gram of water 1° C., or 4.2 J. To boil a cup of water from room temperature (30° C.) to boiling (100° C.), this would require 66,250 J of energy (4.2 J/g×225 g/cup). To do this with a CW laser in 5 minutes, requires a 220 W laser. Consider the effect of a laser having 100,000 watts. What is needed is an on-board system with the autonomous capability to permanently damage or destroy or interdict a CW HELS threat, thereby providing self-protection. These and other deficiencies of the prior art are addressed by one or more embodiments of the present invention. Additional advantages and novel features