Lawrence Livermore National Laboratory (LLNL) researchers have reversed the process that converts electrical signals into sounds, which could lead to a new tool that enhances how computer chips, light-emitting diodes, and transistors are built.
Piezo-electric speakers, often used in cell phones, operate at low frequencies that humans can hear. The LLNL researchers reversed the process and used a very-high frequency sound wave, about 100 million times higher than what humans can hear, to generate light. "This process allows us to very accurately 'see' the highest frequency sound waves by translating them into light," says lead researcher Michael Armstrong.
Very-high frequency sound waves have wavelengths close to the atomic-length scale, and detecting these waves is difficult, but they are useful for probing materials on very small length scales. The new process also does not require any external source to detect the acoustic waves. "Usually scientists use an external laser beam that bounces off the acoustic wave--much like radar speed detectors — to observe high frequency sound," Armstrong says. "An advantage of our technique is that it doesn't require an external laser beam — the acoustic wave itself emits light that we detect."
From Lawrence Livermore National Laboratory
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