IEEE recognizes fiber laser milestone

Fiber lasers and amplifiers can do incredible things, but the technology is not as new as you think. Half a century ago, Elias Snitzer and a handful of colleagues at the American Optical Company's Research Center in Southbridge, MA pioneered both technologies. On October 26, 2012, I attended the dedication of plaque recognizing the achievement as a Milestone in electrical technology by the Institute of Electrical and Electronics Engineers.

Founded in the 19th century to make spectacles, American Optical in 1954 became the first company to try to develop practical fiber-optic imaging bundles, which were first demonstrated by academics and an independent inventor working on shoestring budgets. Initially funded by the Central Intelligence Agency to develop image scrambling bundles for secure messaging, AO later developed imaging bundles.

AO hired Snitzer to work on fiber optics in 1959. At his job interview, he recognized the puzzling patterns in a fiber bundle as evidence of lateral modes, and later published the first analysis of single-mode transmission. Interested in the laser, Snitzer took advantage of AO's glass expertise to make a solid-state laser of glass rather than crystals. He formed barium crown glass doped with 2% neodymium oxide into a three-inch rod thinner than a millimeter, covered with a low-index glass cladding to improve light transmission.  Pumping with a coiled flashlamp like the one Theodore Maiman used in the ruby laser, Snitzer demonstrated pulsed lasing in the stiff neodymium-doped fiber at room temperature in 1961.

In 1963, Snitzer and Charles Koester amplified pulses by up to a factor of 50,000 in a meter-long fiber laser without reflective end coatings, coiled around a linear flashlamp. Their goal was to measure gain dynamics, but the demonstration also showed the potential of fiber amplifiers.

The lack of good pump diodes kept fiber lasers and amplifiers from being practical until the 1980s. Snitzer played an important role in that development, developing doped fiber sensors, demonstrating 1480 nm diode pumping for erbium-fiber amplifiers and developing dual-core fibers now used in high-power fiber lasers. Snitzer died in May, but lived to see developments including multi-kilowatt fiber lasers and high-speed communications through fiber amplifiers in the global telecommunications network. Four of his children who attended the Milestone dedication were pleased by the recognition of the man they knew as "dad."

IEEE Milestone for fiber lasers and amplifiers, across the street from former American Optical headquarters in Southbridge, MA. (Courtesy of Dick Whitney)

Nobel Prize for quantum optics

The award of the 2012 Nobel Prize in Physics to Serge Haroche and David Wineland is the latest in a series of Nobel Prizes honoring elegant experiments using light to illuminate fundamental physics. The Swedish Academy of Sciences cited the two "for ground-breaking experimental methods that enable measuring and manipulation of individual quantum systems." By examining individual photons and atoms, they resolved big questions about quantum mechanics.

Physicists long wondered how seriously they should take the paradoxes that arise from applying quantum mechanics rigorously to the behavior of individual particles. Albert Einstein famously called the concept of entangled particles "spooky action at a distance," but recent experiments have shown that such entanglement is real, and can be used for quantum encryption. Other recent experiments have observed quantum behavior of individual particles, and manipulated that behavior so that quantum states can be superposed for purposes such as quantum computing.

Haroche and Wineland developed complementary techniques for quantum manipulation of single particles. Haroche pioneered cavity quantum electrodynamics, which studies how an electromagnetically resonant cavity can affect quantum properties of an atom contained inside it, including spontaneous and stimulated emission. Working with microwave and optical cavities, his group measured photon properties without destroying the quantum states. Wineland and his colleagues used light to trap ions in ways that allowed them to transfer and superpose states of an ion. They were able to create single-quantum "Schrödinger's cat" states in the laboratory and watch them change from a quantum superposition to a classical mixture. Their work has opened the door to quantum computing and new types of optical clocks. 

Haroche holds the chair in Quantum Physics at the Collége de France (Paris, France), and is well-known for his research in quantum optics and quantum computing, and for his major contributions to cavity quantum electrodynamics, the behavior of atoms and light in high-Q cavities. He is work has earned him a long list of awards, including the Townes Award in 2007 from the Optical Society of America and the Herbert Walther Award from the German Physical Society and OSA in 2010. His deep roots in the optics community include doing his doctoral dissertation under Claude Cohen-Tannoudji and postdoctoral research under Arthur Schawlow, both future Nobel laureates. 

Wineland wrote his doctoral dissertation at Harvard University under Norman Ramsay, another Nobel Laureate, and heads the ion-storage group at the National Institute of Standards and Technology (Boulder, CO). He demonstrated the first laser cooling in 1978, and has used that technique to study quantum mechanics and develop applications. He demonstrated the first single-atom quantum logic gate in 1995, showing the potential of quantum computing, and later demonstrated entanglement of two and four ions. Other achievements include demonstrating quantum teleportation and a quantum logic atomic clock, which is now the world's most precise atomic clock. His long list of awards includes the Schawlow award in laser science from the American Physical Society, OSA's Frederick Ives award, and the first Herbert Walther award in 2008.

David Wineland has won the 2012 Nobel Prize in Physics, along with Serge Haroche. (Image courtesy of
Geoffrey Wheeler/NIST)