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Posts Tagged ‘lasers’

Using light to detect the chemical compositions of molecules from afar is not a new idea, but doing so in uncontrolled environments--particularly in urban environments where the ambient air is cluttered with particulate matter--is extremely difficult. The vast array of compounds in the air can easily cover the telltale signs of an explosive device, and distinguishing between the molecular residues of explosives and various similar benign molecules makes the problem even more daunting.

But the MSU team says it has found a way to use a low intensity laser to make those distinctions even when just a fraction of a billionth of a gram of the explosive materials is present. The beam delivers a one-two punch: short pulses that cause molecules in the air to vibrate and emit signature frequencies that uniquely identify each compound, followed by long pulses that can measure those frequencies and thus identify the molecules.

Just to clarify, these telltale molecules are residuals that are given off by explosive compounds--that is, the explosive itself doesn’t have to be visible or necessarily in direct line of sight. Even buried explosives put off tiny trace molecules into the air, and vehicles boasting a laser molecule scanner could pan the route ahead looking for those indicators of a threat.

To be perfectly fair, we’ve seen IED detectors like this before, and none of them has yet neutralized the IED threat completely (or even mostly). But technologies like this could be huge, given the fact that IEDs account for some 60 percent of coalition soldiers’ deaths, as well as countless more injuries that are often pretty heinous in nature (think: loss of limb). The MSU solution is already partially funded by the Department of Homeland Security, but the team is currently seeking out additional funding to get this technology out of the lab and into the field.

In the first study, researchers at the University of California-Santa Barbara say they’ve built the first working quantum computer chip based on the von Neumann system. Named for the engineer who designed the concept, the von Neumann architecture combines processors and memory, and it’s the basis for every computer out there. (With one notable recent exception.)

This quantum CPU (quCPU?) is a big breakthrough, because quantum computers by definition are difficult to design. They’re based on the concept of superposition — that a quantum bit, or qubit, can exist in two different states at once. Put another way, it can be a 0 or a 1 at the same time, and it can therefore perform calculations more quickly than a system based on 0 or 1. But it’s hard to keep the qubits in a state in which this is possible, and interfering with them — i.e., reading their data — can destroy their superposition capabilities. So, a system that integrates random access memory into the qubits is a big step toward a working computer.

Researchers at UCSB super-chilled their quCPU to near absolute zero and performed a few calculations. Quantum information traveled back and forth among storage and processing elements, and the system performed pretty well — not perfectly, but it’s a start. They also found that the quantum memory can retain information for much longer periods than the qubits, which is also a good sign.

Next, the team is trying to increase the number of quantum devices integrated on a single chip, and they’re studying different metallic materials to make this easier, according to Physics World.

In another quantum paper, researchers in Austria report building the first working quantum simulator — kind of like a quantum computer, but different in scope. It can be used to model the behavior of quantum systems, which can potentially help improve quantum computers.

It would be useful for many reasons to model the behavior of quantum systems, but this is impossible with a traditional computer, as Richard Feynman figured out in 1982. It would take exponential time, with the system working more and more slowly as the calculations increased in number. For a general description of a quantum spin system with 300 particles, a computer would need more memory than exists in the world — even if all of the observable matter in the universe was processed into memory, as the Austrian researchers put it last year. But a quantum simulator, which can complete so many more calculations, would not experience this slowdown. To make one of these, you would have to very carefully control the setup of the simulator, and this is what the Austrians have done.

The team used six laser-cooled calcium atoms as qubits, and used laser pulses to initiate calculations. They found the system could simulate several types of interacting spin systems, according to Science magazine, which published both papers today. The simulator can be reprogrammed to simulate any type of quantum system, the researchers say.

Given breakthroughs like these, quantum computers may be closer than ever.

[Science, Physics World]

In the first study, researchers at the University of California-Santa Barbara say they’ve built the first working quantum computer chip based on the von Neumann system. Named for the engineer who designed the concept, the von Neumann architecture combines processors and memory, and it’s the basis for every computer out there. (With one notable recent exception.)

This quantum CPU (quCPU?) is a big breakthrough, because quantum computers by definition are difficult to design. They’re based on the concept of superposition — that a quantum bit, or qubit, can exist in two different states at once. Put another way, it can be a 0 or a 1 at the same time, and it can therefore perform calculations more quickly than a system based on 0 or 1. But it’s hard to keep the qubits in a state in which this is possible, and interfering with them — i.e., reading their data — can destroy their superposition capabilities. So, a system that integrates random access memory into the qubits is a big step toward a working computer.

Researchers at UCSB super-chilled their quCPU to near absolute zero and performed a few calculations. Quantum information traveled back and forth among storage and processing elements, and the system performed pretty well — not perfectly, but it’s a start. They also found that the quantum memory can retain information for much longer periods than the qubits, which is also a good sign.

Next, the team is trying to increase the number of quantum devices integrated on a single chip, and they’re studying different metallic materials to make this easier, according to Physics World.

In another quantum paper, researchers in Austria report building the first working quantum simulator — kind of like a quantum computer, but different in scope. It can be used to model the behavior of quantum systems, which can potentially help improve quantum computers.

It would be useful for many reasons to model the behavior of quantum systems, but this is impossible with a traditional computer, as Richard Feynman figured out in 1982. It would take exponential time, with the system working more and more slowly as the calculations increased in number. For a general description of a quantum spin system with 300 particles, a computer would need more memory than exists in the world — even if all of the observable matter in the universe was processed into memory, as the Austrian researchers put it last year. But a quantum simulator, which can complete so many more calculations, would not experience this slowdown. To make one of these, you would have to very carefully control the setup of the simulator, and this is what the Austrians have done.

The team used six laser-cooled calcium atoms as qubits, and used laser pulses to initiate calculations. They found the system could simulate several types of interacting spin systems, according to Science magazine, which published both papers today. The simulator can be reprogrammed to simulate any type of quantum system, the researchers say.

Given breakthroughs like these, quantum computers may be closer than ever.

[Science, Physics World]

The premise is simple enough: for the same mass, size, and power load an optical communications system can provide drastically higher data rates compared to standard radio frequency (RF) systems. But it also calls for a trickier setup, requiring a clear line of sight between transmitter and receiver and considerations for variables like weather and atmospheric conditions.

The LCRD aims to demonstrate that a near earth space terminal (in this case a satellite owned by Loral Space & Communications, a partner in the project) can maintain optical communications with ground stations on Earth (one existing station in California and a couple more that will be built) and to test work around for problems that engineers foresee, like the aforementioned weather problem.

Such laser-based data transfers could increase data rates by anywhere from 10 to 100 times. Says NASA via press release:

As an example, at the current limit of 6 Mbps for the Mars Reconnaissance Orbiter (MRO), it takes approximately 90 minutes to transmit a single HiRISE high resolution image back to earth. In some instances, this bottleneck can limit science return. An equivalent MRO mission outfitted with an optical communications transmitter would have a capacity to transmit data back to earth at 100 Mbps or more, reducing the single image transmission time to on order of 5 minutes.

Eventually, the agency hopes to up those speeds such that data transfer speeds from places like the moon and Mars will be super-fast--perhaps fast enough to stream HD footage from the Martian surface, for instance. In the meantime, LCRD will develop the technology-sharing framework and a system of operational standards so private industry can get to work building the optical comms of the future.

By the way, the other two demo projects are pretty awesome as well: A space-based atomic clock to enable a kind of celestial GPS, and a mission-capable solar sail. More via the link below.

[NASA, Discovery News]

Capturing electrons on “film” isn’t easy--imagine the shutter speed you would need to capture something moving so fast that it can rotate a central hub in 151 billionths of a billionth of a second. That’s how fast the electron orbiting a hydrogen nucleus is moving, so in order to capture it in the act you need something with attosecond resolution. In other words, you need a laser capable of pulsing at the attosecond scale.

Attosecond laser pulses have been demonstrated before, but they were too weak to actually measure electron dynamics. For that, you need something both fast and intense. This new laser system satisfies both requirements, and does so with a relatively simple setup.

To get super-short bursts of laser light, you need to combine light waves of different frequencies in a very precise way such that they reinforce each other. This is easier said then done, particularly because it’s hard to get two different laser beams synchronized precisely. To overcome this, the researchers constructed a setup that runs a single laser beam through a beam splitter, producing two beams of different frequencies that are nonetheless the same beam. And because they share the same origin, they remain in sync.

But they’re still not at the attosecond level yet. Several other things have to happen to reach the proper intensities and durations necessary for attosecond-scale measurements. But a paper the team recently published in Nature Photonics outlines the road to attosecond resolutions in such a way that other researchers think its only a matter of time (and, more specifically, a matter of amplification) before we’re looking at individual electrons in a way in which we’ve never seen them before.

[MIT News]

Yesterday, the two defense contractors announced that they are jointly developing a demonstration model Mk 38 with dual capabilities. The chain gun--originally designed to be manually aimed and fired--will now be remote-controlled and use an electro-optical/IR sensor ball to detect and track incoming targets, like UAVs or small watercraft (like the one that perpetrated the attack on the USS Cole in Yemen several years ago).

But according to a BAE-Boeing announcement, “the system also provides the ability to deliver different levels of laser energy, depending on the target and mission objectives.” Danger Room tells us that the fiber laser system can pack up to 10 kilowatts of punch, far below what the U.S. military has previously considered weapons grade but nonetheless effective--just a few months ago an Office of Naval Research laser fried the engine of a small watercraft with a 15 kilowatt beam (though that was designed to be scaled up to a more impressive 100 kilowatts).

Presumably, the Mk 38’s laser package could be upgraded as well, making the death ray part of the system quite a bit deadlier. Which is good, considering that sea air--rife with moisture and particulate stuff that degrades focused laser beams--compounds the many problems inherent in laser weapons systems.

[Defense Tech, Danger Room]

TeraDiode’s system is based on semiconductor laser technology (fueled by electricity rather than chemicals, which is already a plus from a safe-handling standpoint) augmented by an optical system that wrangles several beams of light into a single powerful beam. Powerful enough, the company says, for industrial cutting and welding. Or for blowing stuff up.

Weapons-grade lasers are a tough sell (as regular PopSci readers know from our ongoing boomand bust coverage of the Missile Defense Agency’s Airborne Laser Test Bed), but if TeraDiode’s system can pack as much punch into a small package as the company claims, it could be onto something.

The company sees its lasers someday deployed on ships or tanks, small enough to be mobile but strong enough to down a UAV or perhaps even knock incoming artillery or RPGs out of the air. More near term, it wants to get its direct-diodes on the back of fighter jets to confuse--or perhaps even destroy--incoming anti-aircraft missiles. And TeraDiode isn’t just talking a big game it seems--the company told Xconomy that testing on the aircraft defense system could begin in a year, with deployment in three to five years.

[Xconomy]