Toward Synthesis of Arbitrary Optical Waveforms

摘要

Waveform generation underlies the operation of many electronic devices, especially those used in broadcasting and signal processing. Electronic waveform generators produce a prescribed series of voltages or currents as a function of time, which may then be used as an input for a variety of circuits. The simplest versions of these devices, known as function generators, are used in undergraduate classes to produce the familiar sinusoidal, square, or sawtooth voltage waveforms seen on oscilloscopes. Arbitrary waveform generators (called synthesizers) that can create almost any pulse shape are now a common piece of equipment (and often used by graduate students to test misbehaving electronic equipment). By comparison, synthesizing optical waveforms, in which the electric and magnetic fields of light waves are not simply oscillatory but are specified functions of time, has proved to be difficult. This task has been a long-standing goal of physicists since the invention of the laser in 1960 provided a source of coherent light. On page 1165 of this issue, Chan et al. (J) demonstrate an important step toward synthesizing and characterizing arbitrary waveforms in the optical domain.