Physics To Go is an online monthly mini-magazine and a collection of more than 1000 websites with physics images, activites, and info. You can view an archived version of our January 1, 2010 issue, Laser 50th anniversary below, or click to see our September 1, 2013 issue, Two views of Earth.

Physics in Your World

Lasers light up blood-flow dynamics image
Image credit: Michael Smith, Institute for Biodiagnostics, Winnipeg, Canada; image source; larger image

Lasers light up blood-flow dynamics

If you shine a laser beam at a small angle to a piece of white paper, so the beam spot spreads out, you'll see what is called a speckle pattern (do this experiment with adult supervision). If you shine the beam on your skin, you'll see a different kind of pattern.

The image shows how laser speckle imaging can show the difference between normal blood flow, in the finger on the left, and increased blood flow due to the warming of the skin (the figure on the right was immersed in hot water). To find out more, see Lasers light up blood-flow dynamics.

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Physics at Home

PhET Simulation: Lasers

Security note:
Once you have clicked on the "simulation" link below, be sure to read the Java Security Advisory before running the simulation: To do that, click the "Read now" button on the yellow band near the top of the PhET page.

See if you can produce a laser beam in this simulation from the University of Colorado. Excite the laser's atoms with lights of different wavelengths and control components of the laser to create the beam.

(This feature was updated on May 5, 2013.)


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From Physics Research

Michigan laser beam believed to set record for intensity image
Image credit: Anatoly Maksimchuk/EECS; image source; larger image

Michigan laser beam believed to set record for intensity

You don't want to stand in front of the HERCULES laser beam at the University of Michigan. In February of 2008, U-M physicists produced the most intense beam of light ever observed.  Read more at Michigan laser beam believed to set record for intensity.


Worth a Look

LaserFest

LaserFest is the year-long celebration of the laser, marking the fiftieth anniversary of its invention. Check out LaserFest to learn more about the event.

To learn about the development of the laser, read these articles from Bell Labs and SPIE, and also see this LaserFest timeline.


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