For performing high-end physics, ordinary oscilloscopes and televisions aren't fast enough, and the deflection of a beam used to display an image or a short-lived signal requires a different technology, which sometimes goes by the name "streak camera." Because the electrons comprising the beam are charged particles, the signals they carry suffer unavoidable blurring where the signal strength is strongest, thereby limiting the useful dynamic range. John Heebner and colleagues at Lawrence Livermore National Lab (LLNL) recently devised a solid-state all-optical streak camera, the first to attain a time resolution near 1 picosecond while simultaneously preserving a wide dynamic range, 3000:1. In his camera, the beam being deflected consists not of charged electrons but of uncharged photons, which do not suffer from the limitations of conventional streak cameras.
He achieves an unprecedented deflection rate of a light beam by sending it through an ordinary planar waveguide whose optical properties can be nearly instantaneously modified by a separate pump laser beam incident from above. A sequential array of "transient" prisms is created by first allowing the pump beam to pass through a serrated mask. When the pump beam is properly synchronized to the signal beam to be recorded, time-of-flight at the speed of light does the rest. Because later portions of the signal encounter more prisms, that part of the signal is deflected by a greater amount than the earlier portions of the signal that had already advanced through the waveguide before the prisms turned on. The prisms persist for the duration of the sweep and disappear in time for the process to start again with the next trace. Each deflected light trace is
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Optical Society of America