Quantum Dots and Nanotechnology Cloak Military Targets From Laser Guided Weapons

Science Applications International Corporation ((SAIC) San Diego, CA) received U.S. Patent 7,742,170 for a nanotechnology method and system for countering laser technology.  The systems use nanocomponent material that is tailored to cloak or obscure a target from detection by transmitted laser radiation. The nanodot material absorbs and/or down-converts the transmitted laser radiation.

SAIC Inventors Scott Earl McNeil,  Martin Joseph Fritts, Roy Reed Heddleston and Martin B. Mark similarly, describe  a method and system for providing a countermeasure against laser systems intended to blind a target through the use of a specifically engineered nanocomponent material for absorbing and/or down-converting the radiation from the laser system.

Different sets of nanodots having different absorption and emission wavelengths are utilized in a countermeasure method and system that includes both cloaking and decoying. More specifically, in for example, a combat situation where numerous tanks, trucks, and other potential envoy targets may be targeted by a laser beam-rider weapon, targets containing actual supplies, weapons, humans, etc. are coated with cloaking nanodots, i.e., nanodots that are tailored to absorb the transmitted laser radiation and reflect the detectable reflection wavelength at below threshold levels and emit reflected radiation in an undetectable wavelength due to down-conversion of the transmitted laser radiation.

At the same time, remotely controlled decoy targets that do not contain actual supplies, weapons or humans are coated with nanodots specifically tailored to absorb the transmitted radiation and emit the reflected radiation specifically within the wavelength of the detector, above the threshold level.  In response to the positive identification received in response to the transmitted laser radiation, the user may decide to destroy the target using a weapon directed to the identified target. According to this embodiment, an enemy may be tricked into believing that they are destroying targets within the envoy, when in fact they are destroying non-essential targets within the envoy, while the essential targets remain cloaked and intact. Reconnaissance by the enemy will falsely suggest that key targets have been destroyed, when in the fact the destroyed targets are decoys.

Summary of the Problem

Light detection and ranging (“LIDAR”) which uses the same principle as RADAR, is used to detect and provide range information for numerous targets. In operation, an instrument based on LIDAR concepts transmits light out to a target. The transmitted light interacts with and is changed by the target. Some of this light is reflected/scattered back to the instrument where it is analyzed. Instruments utilizing LIDAR include, for example, laser rangefinders, laser beam-rider missiles, and laser target designators. The change in the properties of the light enables some property of the target to be determined. The time for the light to travel out to the target and back to the LIDAR receiver is used to determine the range to the target. In certain situations, e.g., military situations, there is a need to mask or counteract the effects of LIDAR in order to protect the target from detection.

Currently available cloaking technologies, e.g., based on organic dyes, rare earth materials and fluorescent pigments, are expensive and susceptible to variations in environmental constraints, e.g., temperature and precipitation. There is a need in the art for a method and system for cloaking targets from the effects of LIDAR.

Laser generated effects are also used to temporarily or permanently blind individuals. For example, laser dazzlers or laser dissuaders are used by, for example, police, armed forces, or even civilians to temporarily blind a suspect, enemy or the like using laser radiation at or below the permanent eye damage threshold. Consequently, there is a need in the art for a method and system for counteracting or negating the laser generated effects.

Currently, there are a variety of detectors, shields and obscurants that are used to detect and/or counteract or shield the effects of laser-based threats. Laser-based threats are used in a variety of capacities to do everything from locating and destroying tanks, artillery, planes, ships, cargo vans and other targets to temporarily or permanently blinding individuals.

Certain laser warning receivers utilize technology that detects and prioritizes the threat level of a laser-based threat and transmits audible and visual warnings on or through a display. This technology serves to indicate to the crew when a target, such as reconnaissance vehicles, armored personnel carrier or main battle tank has been targeted by the laser-based threat, so that the crew may be able to take evasive action, if necessary.

Crewmembers are alerted that an enemy has either completed a firing solution or that a precision-guided munition or beamriding is heading for their vehicle. Similarly, laser-warning receivers for aircraft detect laser radiation and use signal processing to determine the type of threat and the direction of its source. These electro-optical countermeasures consist of externally mounted sensor units and an inboard interface unit comparator and associated test equipment.

Further, to protect the eye from laser irradiation in the visible to near-IR region, technology has been developed in the form of filter inserts for soldiers’ eyewear, also called ballistic and laser protective spectacles (BLPS). The BLPS are dye-filled polycarbonate plastic filters which will protect eyesight against low-energy lasers, specifically the two or three wavelengths used by common range finders and target designators based on Nd:YAG and ruby lasers. The BLPS will not give protection against frequency-agile low energy laser weapons. The filters can provide up to three notches before reception is impaired. To protect thermal imagers from laser irradiation in the far IR spectral region, a filter is employed in front of the sensitive detectors.

Other laser-based threat protection mechanisms include the use of organic absorption dyes to absorb the laser radiation, reflection of the laser radiation using optical coatings or other effects that alter the reflective properties of an intended target’s surface, and the blocking of specific wavelengths.

Finally, in certain situations, attenuative properties of smoke, dust, dirt and other particulates allow it to serve as a passive defense against blinding laser weaponry. Large-area smoke generation provides a means for continuous protection for forward elements of U.S. combat forces.

The SAIC method for countering target detection by a laser detection device includes engineering a first nanocomponent material to absorb at a first transmitted radiation wavelength of a first laser detection device; and applying the first nanocomponent material to the target, wherein at least a portion of the first transmitted radiation wavelength of the first laser detection device is absorbed by the first nanocomponent material such that a first reflected radiation wavelength from the target is below a level that is detectable by the first laser detection device.

Tailored nanodots are utilized as an obscurant in order to counteract the blinding effects of certain lasers. In a particular example, the nanodots are tailored to absorb the transmitted laser radiation as described above and then the nanodots are encapsulated due to their small size, i.e., on the order of a couple of angstroms. The incorporation or encapsulation may be within a polymer, e.g., a polymer matrix such as polystyrene or PMMA (Polymethylmethacrylate). The encapsulated nanodots are on the order of 1 up to 100 microns. This size is significant due to the fact that nanodots of this size will have the characteristics of a gaseous medium and behave as a gas when released into the air.