#laser

Are Lightsabers Theoretically Possible?We all recall the first time we saw a lightsaber deployed in a Star Wars movie, because they were just so cool. But can anything like this technology ever come to exist, or is it just magical? Gizmodo asked two physicists and a photonics professor about the possibility. Dennis K. Killinger of the University of South Florida explains how such a laser weapon wouldn't work as it does in the movies. The one aspect of lightsabers that seems infeasible is the concept of its acting as a solid physical rod or saber that can “hit” or “strike” an opponent. In the movies the mechanical hitting of the dueling lightsabers is enforced by sound effects—the lightsabers have a “hum,” and you can hear them hitting each other. But if you take two flashlight beams and cross one beam with the other beam, there is no sound or force experienced by one light beam on the other. This is because photons have no mass, which means that a laser or optical beam has no mass. To get the point across: I like to say that “You can’t use a light beam to hammer a nail.” So in this sense, it is not feasible that two laser beams can “hit” each other in the mechanical sense. However, there is a scientific exception to this: as discovered by recent physics Nobel Prize winner A. Ashkin, a laser beam under the right conditions can be used as an optical trap or as an optical tweezer to trap and move very small objects, such as a bacteria. While one could stretch the truth and call this a Star Wars Tractor Beam, there is a 1,000 billion billion times difference between moving a bacteria and the mass of a starship (ie. SpaceX second stage starship.) However, the experts agree that if "lightsaber" is a misnomer and the actual weapon is made of plasma particles, that opens up all kinds of possibilities, none of them yet feasible. Read what they all have to say at Gizmodo.#lightsaber #starwars #laser

Glass Nanosphere at its Quantum Limit as Scientists Slowed its Motion to the Lowest Quantum StateThat tiny speck in the middle of the picture above is a glass nanosphere measuring 100 nanometer across (about 100 smaller than the width of a human hair).It's pretty small, but relatively large when compared to atomic-level stuff that scientists used to work with. Over time, physicists have continued to put ever larger objects at their quantum limit by cooling them down to near absolute zero.Now, researchers at ETH Zurich have managed to trap the tiny glass nanosphere using laser and slowed its thermal motion to the lowest quantum mechanical state.From ETH Zurich:The macroscopic object in [professor Lukas Novotny’s] laboratory is a tiny sphere made of glass. Although it is only a hundred nanometres in diameter, it consists of as many as ten million atoms. Using a tightly focused laser beam, the sphere is made to hover in an optical trap inside a vacuum container cooled down to 269 degrees below zero. The lower the temperature, the smaller is the thermal motion. “However, to clearly see quantum effects the nanosphere needs to be slowed down even more, all the way to its motional ground state”, explains Felix Tebbenjohanns, a postdoc in Novotny’s lab. The oscillations of the sphere, and hence its motional energy, are reduced to the point where the quantum mechanical uncertainty relation forbids a further reduction. “This means that we freeze the motional energy of the sphere to a minimum that is close to the quantum mechanical zero-point motion”, Tebbenjohanns says.While much of the scientific findings are academic, this achievement may one day help in creating a much more sensitive sensor technology.#quantumphysics #laser #nanosphere #glassImage: ETH Zurich

Scientists Used Optical Tweezers to Create a Mario Animation ... and the World's Most Powerful Quantum ComputerMikhail Lukin and colleagues at the Harvard Quantum Initiative used optical tweezers to arrange single atoms in sequential frames into a fun video clip featuring our favorite plumber Mario.But fun aside, the new technique - which uses focused laser beams - has enabled them to develop a special type of quantum computer called a programmable quantum simulator capable of operating with 256 quantum bits or "qubits."From The Harvard Gazette:“The number of quantum states that are possible with only 256 qubits exceeds the number of atoms in the solar system,” [physics student and study lead author Sepehr Ebadi] said, explaining the system’s vast size.“The workhorse of this new platform is a device called the spatial light modulator, which is used to shape an optical wavefront to produce hundreds of individually focused optical tweezer beams,” said Ebadi. “These devices are essentially the same as what is used inside a computer projector to display images on a screen, but we have adapted them to be a critical component of our quantum simulator.”The initial loading of the atoms into the optical tweezers is random, and the researchers must move the atoms around to arrange them into their target geometries. The researchers use a second set of moving optical tweezers to drag the atoms to their desired locations, eliminating the initial randomness. Lasers give the researchers complete control over the positioning of the atomic qubits and their coherent quantum manipulation.#quantumcomputing #Mario #opticaltweezer #atom #laser #quantumphysics

Pew Pew! This Smart Farming Robot Kills Weeds with LaserIf your garden got weeds, killer robot with lasers doesn't usually come to mind as a solution but that's exactly what Carbon Robotics offered for future farmers.Behold the Autonomous Weeder, a smart farming robot that lets farmers get rid of weed from their farm lands without the use of herbicide. The robot scans the ground with its 12 cameras as it drives down rows of crops. An onboard AI analyzes the images and once it identifies weeds, it directs the robot's carbon dioxide lasers to zap and kill them.While not having to use ecologically harmful herbicide is great, the bonus here is that the autonomous robot can eliminate more than 100,000 weeds per hour and can weed 15 to 20 acres of crops per day (it can even work at night), compared to a farm laborer who could only weed about 1 acre in a day.#weed #robot #farming #laser #FarmingEquipmentvia Technabob