NIST/JILA physicist wins award for contributions to laser technology
Two of recipient Steven Cundiff’s contributions include the development of the “dark pulse” laser and a GaAs-based terahertz radiation laser.
Steven Cundiff, a physicist at the National Institute of Standards and Technology (NIST), has received the 2011 William F. Meggers Award from the Optical Society of America (OSA).
The Meggers Award recognises outstanding work in spectroscopy, the study and measurement of interactions between light and matter. Meggers was a prominent scientist who worked at NIST (then called the National Bureau of Standards) from 1914 to 1958 and is considered by many to be the founder of the American field of spectroscopy.
Cundiff, a Fellow of JILA, a joint institute of NIST and the University of Colorado Boulder, is cited for "contributions to the field of ultrafast spectroscopy of semiconductors, including multidimensional Fourier transform techniques, and for contributions to the development of femtosecond frequency comb technology."
In previous studies he was involved in, samples made of thin layers of GaAs were hit with a continuous series of three near-infrared laser pulses lasting just 100 femtoseconds each. Trillions of excitons (excited electrons and the “holes” they left behind) were formed as they jumped to higher-energy vibration patterns.
The researchers identified a subtle coupling between pairs of excitons with different energy levels. The experimental data matched advanced theoretical calculations of the electronic properties of semiconductors, confirming the importance of the collective exciton behaviour—and dramatically demonstrated the superiority of those calculations over simpler models of semiconductor behaviour.
Cundiff was also key to the development of the “dark pulse” laser, which contrary to a typical pulsed laser, excels at not producing light. This type of laser, made of III-V quantum dots, is envisioned as a tool for benign communications and measurements based on infrared light frequencies. The laser’s ultrashort pulses span just 90 picoseconds (trillionths of a second), making the device suitable for measurements on short timescales. Dark pulses might be useful in signal processing because, unlike bright pulses, they generally propagate without distortion.
Cundiff also helped to develop a GaAs-based terahertz radiation laser that is unusually efficient and less prone to damage than similar systems. The technology might be useful in applications such as detecting trace gases or imaging weapons in security screening and can be used to detect many substances that have unique absorption characteristics at these wavelengths.