April 2010

Lasers and Optics for Measuring Tooth Decay

Daniel Fried

Lasers may finally provide dental patients a good reason to open up and say ahhhh. Dentists are already using optical technologies to detect tooth decay and lasers for therapeutic interventions, and they are looking to a future in which they can combine these methods for minimally invasive dentistry.

Mode Harnessing for Laser Diodes

Recent experiments have shown that the modal structure of broad-area edge-emitting semiconductor lasers is box-like, with each lateral mode having a distinct wavelength. Thus, researchers can now reshape lateral modes and effectively combine all multimode laser output into a single-mode fiber. This approach provides a promising means for delivering high-power, high-speed modulated beams of any wavelength that are directly radiated from semiconductor lasers.

Telescope Lens-Making in the 17th Century: The Legacy of Vangelista Torricelli

In the early days of instrumental optics, the know-how of lens making was shrouded in secrecy. A remarkable exception can be found in a letter from 1643, in which the Italian lens-maker Vangelista Torricelli gives his correspondent directions on optical shop practices.


A Large, Real-Time 3-D Display

Quantum Cascade Lasers Gain Efficiency

Did You Know?

Profiles in Optics: Wallace R. Brode

When Is Science Valid?


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