Experiments with Lasers

I found this great video and made the translation.
I hope you can enjoy it.



You can found another cool experiments here:

• http://www.west.net/~science/laser.htm
• http://www.juliantrubin.com/topicprojects/laser_projects.html
• https://www.asme.org/career-education/articles/k-12-grade/laser-experiments-to-share-with-your-kids
• http://www.superchargedscience.com/documents/Laser%20Experiments.pdf
• http://physicscentral.com/experiment/physicsathome/laser-jello.cfm
• http://scitoys.com/scitoys/scitoys/light/light.html
• http://laserclassroom.com/category/laser-and-light-experiments-and-lessons/
• http://laserfest.org/resources/lessons.cfm
• http://www.sciencebuddies.org/science-fair-projects/project_ideas/Phys_p009.shtml

CAUTION: Don't point a laser to your eyes. It's recommend an adult supervisor to all the experiments.

STOP that light

Credit: Adrian

The fastest thing in the universe was completely stopped and stored for a minute (new record). In vacuum, light travels about 18 million kilometers, in those 60 seconds - which represents more than 20 trips to the moon and back.

"A minute is a very, very long," says Thomas Krauss, St. Andrews University, UK. "This is really an important milestone."

The exploit could allow secure quantum communications to work at long distances.

As the light typically travels just under 300,000 kilometers per second in a vacuum, physicists  were able to slow it down just to only 17 meters per second in 1999, and two years later, stop it completely, though only by a fraction of a second. Earlier this year, researchers increased this time stopping the light for 16 seconds using cold atoms.

Light Trap

To break the minute barrier, George Heinze and colleagues at the University of Darmstadt, Germany, fired a laser control over an opaque crystal, the atoms leading to a quantum superposition of two states. This made it clear to a small range of frequencies. The Heinze's team then stopped a second laser beam which entered the crystal, turning the first laser off and, consequently, the transparency of that crystal disappeared.

The storage time depends upon the crystal's superposition. A magnetic field extends it, but it complicates the configuration of the control laser. Heinze's team used an algorithm to "generate" the magnets and laser combinations, leading them to trap the light for a minute.

Should still be possible to achieve longer storage of light with other crystals, Heinze says, as they did with the physical limits of this material.

Fonte: newscientist

Journal reference: Physical Review Letters, doi.org/m86

Most powerful X-ray laser

This photograph shows the interior of a Linac Coherent Light Source SXR experimental chamber, set up for an investigation to create and measure a form of extreme, 2-million-degree matter known as “hot, dense matter.” The central part of the frame contains the holder for the material that will be converted by the powerful LCLS laser into hot, dense matter. To the left is an XUV spectrometer and to the right is a small red laser set up for alignment and positioning. Credit: University of Oxford / Sam Vinko

Researchers working at the SLAC National Accelerator Laboratory have used the world's most powerful X-ray laser to create and probe a two-million-degree piece of matter in a controlled way for the first time. This feat, reported today inNature, takes scientists a significant step forward in understanding the most extreme matter found in the hearts of stars and giant planets, and could help experiments aimed at recreating the nuclear fusion process that powers the sun.

in PhysOrg

Lasers to force rain

Scientists working on technique to use lasers to force rain

(PhysOrg.com) -- As with many of man's most basic ancient desires; to be able to fly, to become invisible etc. making it rain on command (or by prayer) has always been high on the list, and up to now, has proved more elusive than other advances in the sciences. Now however, physicists in Switzerland might have finally made a breakthrough. In their paper published in Nature Communications, they describe a method whereby a laser is used to create nitric acid particles in the air to which moisture will gravitate forming droplets.

Experimental setup. Image: NPG, doi:10.1038/ncomms1462

A group of scientist with a Teramobile mobile femtosecond-Terawatt laser system start firing it into the sky (on a very humid day - over 70%) for 113 hours. To ensure their results were constrained to one area, wind shields were used. They then sampled the aerosols alternatively at 2 cm distances in the areas where they expected to see nitric acid particles form. In so doing they found that their efforts did indeed result in the creation of nitric acid particles which caused water droplets to form on the order of a few microns in size.

The tiny drops are not heavy enough to fall as rain. But this is a good start.

NASA - Using LIDAR - v2D

Want to know the 3D shape of terrain on another planet? Want to study the height and density of Earth's forests? An amazing tool called LIDAR can help! Learn more in this video.