Video Above: Drone Fighter Jet vs. Manned Fighter Jet .. Who Wins?
By Kris Osborn - Warrior Maven
(Washington, D.C.) Lasers can already incinerate drones, destroy enemy aircraft and possibly even melt incoming anti-ship missiles, but the Army Research Office is fast progressing with new research enabling lasers to transmit data at the speed of light.
While early on, it is potentially a huge breakthrough, as promising new experiments are showing that laser communications can instantly network robots, drones, sensors, weapons and platforms. The work, now being done by the University of Pennsylvania and Duke University, is based upon the science of Photonics, which an Army Research Office essay says “has the potential to transform all manners of electronic devices by storing and transmitting information in the form of light, rather than electricity.”
There are still many challenges to resolve, the ARO paper explains, yet the breakthrough introduces great promise, as lasers could transmit sensitive data across multiple nodes at the speed of light, exponentially faster and potentially more secure than RF communications.
“In order to preserve the information manipulated by a photonic device, its lasers must be exceptionally stable and coherent. So-called single-mode lasers eliminate noisy variations within their beams and improve their coherence, but as a result, are dimmer and less powerful than lasers that contain multiple simultaneous modes,” the ARO paper says.
Researchers have been working on two-dimensional arrays of microlasers that achieve what scientists called greater “power density,” yet the beams still need to be stabilized.
Dr. James Joseph, program manager, ARO, explained in the essay that The ARO, which funds Army-oriented cutting-edge research, is an element of the U.S. Army Combat Capabilities Development Command, Army Futures Command.
“One seemingly straightforward method to achieve a high-power, single-mode laser is to couple multiple identical single-mode lasers together to form a laser array,” Dr. Liang Feng, associate professor in the departments of Materials Science and Engineering and Electrical and Systems Engineering at University of Pennsylvania, said according to the ARO essay.
Drone vehicles, robots and advanced sensors could all benefit from these types of innovations, as targeting or terrain-mapping data could be quickly sent to human decision-makers through these focused, high power-density lasers able to share between an interconnected series of nodes in a “meshed” network.
The other potentially significant advantage would likely be in the area of range, meaning greatly dispersed combat nodes miles away could share time-sensitive data with virtually no latency, something bringing critical implications when it comes to reducing sensor-to-shooter time. Lasers, being light energy instead of electricity, are much less likely to be hacked, jammed or interrupted by cyber or EW attacks. Perhaps a high-altitude surveillance plane detects enemy movement in a densely populated area about to come into direct contact with infantry and then instantly transmits images, data-points and target details to ground forces in position to attack? Maybe multiple beams could be sent at one time, expanding force awareness of target locations, maneuver strategies and methods of attack.
Researchers from the University of Pennsylvania and Duke University, with Army funding, designed and built two-dimensional arrays of closely packed micro-lasers that have the stability of a single micro-laser but can collectively achieve power density orders of magnitude higher. They published a study in the peer-reviewed journal Science demonstrating the super-symmetric micro-laser array.
Robots and autonomous vehicles that use LiDAR for optical sensing and ranging, manufacturing and material processing techniques that use lasers, are some of many other potential applications of this research.
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“Single-mode, high power lasing is used in a wide range of applications that are important to the Army and help support the warfighter including optical communications, optical sensing and LIDAR ranging,” said, known as DEVCOM, Army Research Laboratory. “The research results out of UPenn mark a significant step towards creating more efficient and fieldable laser sources.”
The way information can be layered with this technology could also have important implications for photonic computers and communication systems.
“Intuitively, this laser array would have an enhanced emission power, but because of the nature of complexity associated with a coupled system, it will also have multiple super-modes. Unfortunately, the competition between modes makes the laser array less coherent.”
Coupling two lasers produces two super-modes, but that number increases quadratically as lasers are arrayed in the two-dimensional grids eyed for photonic sensing and LiDAR applications.
“Single mode operation is critical because the radiance and brightness of the laser array increase with number of lasers only if they are all phase-locked into a single super-mode,” said Xingdu Qiao, doctoral candidate at University of Pennsylvania. “Inspired by the concept of supersymmetry from physics, we can achieve this kind of phase-locked single-mode lasing in a laser array by adding a dissipative super-partner.”
In particle physics, super-symmetry is the theory that all elementary particles of the two main classes, bosons and fermions, have a yet undiscovered super-partner in the other class. The mathematical tools that predict the properties of each particle’s hypothetical super-partner can also be applied to the properties of lasers.
Compared to elementary particles, fabricating a single micro-laser’s super-partner is relatively simple. The complexity lies in adapting super-symmetry’s mathematical transformations to produce an entire super-partner array that has the correct energy levels to cancel out all but the desired single mode of the original.
Prior to this research, super-partner laser arrays could only have been one-dimensional, with each of the laser elements aligned in a row. By solving the mathematical relationships that govern the directions in which the individual elements couple to one another, this new study demonstrates an array with five rows and five columns of micro-lasers.
“When the lossy super-symmetric partner array and the original laser array are coupled together, all the super-modes except for the fundamental mode are dissipated, resulting in single-mode lasing with 25 times the power and more than 100 times the power density of the original array,” said Dr. Zihe Gao, a post-doctoral fellow in Feng’s program, “We envision a much more dramatic power scaling by applying our generic scheme for a much larger array even in three dimensions. The engineering behind it is the same.”
The study also shows that the technique is compatible with the team’s earlier research on vortex lasers, which can precisely control orbital angular momentum, or how a laser beam spirals around its axis of travel. The ability to manipulate this property of light could enable photonic systems encoded at even higher densities than previously imagined.
“Bringing super-symmetry to two-dimensional laser arrays constitutes a powerful toolbox for potential large-scale integrated photonic systems,” Feng said.
In addition to the Army, the National Science Foundation and a Sloan Research Fellowship also supported this research.
Kris Osborn is the defense editor for the National Interest. Osborn previously served at the Pentagon as a Highly Qualified Expert with the Office of the Assistant Secretary of the Army—Acquisition, Logistics & Technology. Osborn has also worked as an anchor and on-air military specialist at national TV networks. He has appeared as a guest military expert on Fox News, MSNBC, The Military Channel, and The History Channel. He also has a master’s degree in Comparative Literature from Columbia University.