Pew Pew!: 5 Incredible Lasers That Will Change The World

5 LISA Pathfinder

Matter tells space how to curve, space tells matter how to move, and we worked out both with a nervous system designed to hunt bananas. (The only real "life hack" is our entire consciousness). Gravity is the most obvious of the four fundamental forces, but it's also the weakest, which is why we usually observe spacetime curvature using entire galaxies across billions of light-years. The LISA Pathfinder will do it in 38 centimeters.

Physicists often simplify problems by ignoring things, approximating the answer by getting rid of confounding complications. LISA Pathfinder will do it for real. The spacecraft will leave Earth behind to find some peace and quiet, flying to a relatively undisturbed area of the Solar System where it'll use its own hull to shield the two most beautiful cubes in existence from the rest of that existence.

Each cube is 1.96 kg of polished perfection, a 46-mm-sided regular hexahedron of gold-platinum alloy. This material is used because it has a low magnetic susceptibility, not just to make a prize higher than Olympic gold for shot put far above and beyond the call of gravity.

The cubes will float inside LISA-P. Lasers will track how far it is from them to within a billionth of a meter, firing liquid metal ion thrusters to maintain the correct distance. This will be the Solar System's only smart game of "not touching you, can't get mad or inaccurate." Laser interferometry will also track the distance between the cubes down to the picometer. Flying through the heavens while measuring things accurate to trillionths of a meter. If angels did dance on the head of a pin, this system could read their shoe size.

The cubes will fly in almost perfect free fall, protected from everything else in existence, their motion tracing geodesics across the surface of spacetime. We're throwing stones not to see the splash but to surf the shape of reality itself. So LISA will go up high, find something precious inside itself, create an inner calm so that nothing can disturb it, feel the harmonics of light bouncing back and forth between the shining centers, and use this inner harmony to map the shape of the universe. This is a Zen spacecraft.

4 ATHENA Laser Blaster

Some people are disappointed that modern lasers don't just vaporize enemies, which is like being disappointed that modern sticks are used for airplanes and building bridges instead of killing cave people. But Lockheed Martin developed the answer to that problem anyway. In fact, it's the answer to any problem, up to and including COBRA plots in GI Joe.

The Advanced Test High Energy Asset (ATHENA) is a 30-kW laser, and exactly what happens when someone watches Real Genius and adds 30 years of technological progress. The ATHENA is named for the goddess of wisdom, inspiration, war, mathematics, and skill, and every single one of those applies to the result. As do other divine emotions, like "awe," "fear," and "weeping at the terrible beauty."

In a test, ATHENA "disabled" a truck engine by melting a hole in it from over 1,600 meters away. Another test of her predecessor, ADAM, punctured multiple compartments of a small military boat. New weapons often inspire dystopian fears, but this is a system of hope. Think of it: If Michael Bay's Transformers ever starts happening for real, we'll be able to shut that shit down in 30 seconds instead of three hours.

Fiber lasers are what happen when fiber optics decide the only information they need to carry is "goodbye." ATHENA ups the power by combining multiple fiber laser modes into one output beam. The result is a cable which keeps amplifying the light the longer it gets and is flexible enough to aim the output. We invented laser hoses.

3 Optical Mobius Strip

They say that if you love it, you should put a ring on it. An international group of scientists love laser physics and made a ring of it, proving their love of existence with the smartest symbol of understanding they could conceive of. The result was an optical Mobius strip, twisting the polarization of laser light into a one-sided surface. Forget cowboys firing guns to make people dance -- scientists fired a laser which made light itself spin incredible pirouettes. They directed the beam through a liquid crystal q-plate, and that's a more Star-Trek-sounding scientific component than a warp drive. This plate split the incoming beam into two parts, which were recombined and focused down to create the optical Mobius strip.

That's not a beam of light racing around in a circle. The light is moving down in that picture, in the direction of the green arrow, with an oscillation forced away from its own center and twisted into a Mobius strip. They also increased the twist with a different q-plate to create this beautiful star-Mobius.

They observed the resulting pattern with a gold nanoparticle, scanning a speck of precious metal through the pattern to read out the electromagnomobius. Because there's no collection of awesome ideas we won't make real. They took the cutting edge of laser physics and twisted it into mathematical beauty. Even the phrase "structured light" is our intelligence given form (as well as a potential tool for making metamaterials).

This is a work of exquisite electromagnetic art. It makes the Mona Lisa look like the result of a bald monkey splattering oil over a chunk of dead tree, which is exactly what it is. They say the line between genius and insanity is thin. That's because it's a 530-nanometer green laser beam twisted into nonorientable compact manifold, built to remind us that this line leads to the future.

2 Matter Waves Measure Spacetime

Laser interferometry is when we split laser beams into two waves, then recombine them to measure the difference. Atom interferometry is when we split matter into two waves, and recombine them to measure the difference. And this isn't a revolutionary new technique. We've been doing this for decades. We worked out quantum matter waves before Star Trek worked out it was time to stop using the original actors.

Popular culture keeps acting like quantum mechanics is a crazy theory that nobody really understands, but that's like calling electricity newfangled. Quantum mechanics is already at the core of every electronic device you use (semiconductors being just one of the more ubiquitous examples). We don't understand all of quantum mechanics in the same way somebody might not have read an entire library -- they're still much, much more capable than they were before.

We've all heard that light can act as a particle or a wave. So can matter -- it's just that matter's wavelength is so tiny that we can't experience it without getting extremely smart about it. But getting extremely smart about it is how humanity has made every advance in history. We now use that incredibly small wavelength to make incredibly accurate measurements. We split clouds of supercooled atoms into two groups by blasting them with laser pulses. The matter waves of those groups interfere, and we read the result with more laser pulses. Lasers are our sonic screwdriver: There's almost nothing we can't do with them.

Remember that the next time you see someone say "quantum" to excuse some hand-waving "woooo" bullshit. We built quantum wave interferometers in the same year Marky Mark and the Funky Bunch released "Good Vibrations," proving humanity has long been capable of achieving an array of incredible things.

Just one recent example: An international group of scientists at the Universities of Florence and Bologna, with the European Space Agency, used it to measure gravitational curvature. They threw three supercooled atom clouds of rubidium atoms straight up simultaneously, then fired a sequence of lasers to split and recombine them. The resulting fringes of quantum-interfering matter allowed them to measure not just the local gravity, and the slope of that gravity, but the curvature of Earth's gravitational field with incredible accuracy. They used the smallest waves we can control to measure the makeup of our entire planet.

1 Stopping Light (Then Starting It Again)

Light is the fastest anything in existence. Unless we say otherwise. It's fairly easy to stop light (you can do it by closing your eyes), but a team at the University of Darmstadt stopped light, held it motionless for over a minute, then sent a signal to let it continue on its way.

A probe laser pulse was frozen in a supercooled Praseodymium-ion-doped Yttrium Orthosilicate crystal, because all laser-based scientific research is required by law to sound like exposition dialogue from a 1950s B-movie. How did we make this material freeze lasers? With more lasers, because that's always the most awesome solution. Preparation laser pulses set up the crystal's quantum states, then a "write" pulse induced Electromagnetically Induced Transparency (EIT). Our laser tells the material to be transparent, allowing the probe pulse to pass into the material. We literally fire lasers at matter until it does what we say. Then the "write" pulse is turned off while the probe is still inside, removing the transparency, and the probe pulse is trapped.

But instead of being destroyed, the probe is encoded into the quantum energy levels of the atoms. External magnetic fields hold them stable for over a minute, which in quantum terms is infinity plus a zillion years. A "read" pulse from the control laser renders the material transparent again, and probe light shines out. They were able to recover probe pulses and images sixty seconds later this way. The light should have moved 18 million kilometers in that time. We held it inside a three millimeter crystal.

Stopping light like this could be useful for quantum computation and communications, if you're the sort of person who could see people stopping light and then need another reason to be impressed.

We've always been told that someone powerful once said, "Let there be light."

Humanity's response? "When we say so."

Continue your education with The Focal Length of Whiskey and Mario's Terrifying Implications For Physics.

Light up your mind with 9 Badass Lasers That Prove The Death Star Isn't Far Off and The 5 Smartest Things Humanity Has Done (Recently)

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