Physicists from Emory University have led work to develop a microscopic, nonlinear light source that can be switched on, off or tuned to a particular intensity by an electrical "knob." The paper is published in the journal Optica, and could aid in the design of smaller, more flexible technologies for communications, sensing and quantum computing.
The new method focuses on a type of nonlinear optics known as second harmonic generation (SHG), where two photons of the same frequency interact with a material and combine into a single photon with twice the frequency.
"Nobody had previously shown that you can tune second harmonic generation with an electric knob in such a small device," says Hayk Harutyunyan, senior author of the paper and Emory professor of physics.
The entire integrated component is a little more than 200 nanometers wide, or more than 100 times smaller than the width of a human hair. The active area, where light is generated, is just two to six nanometers wide—tens of times smaller than most preexisting devices for second harmonic generation and far more controllable.
"We can switch on our device, completely shut it off, and raise or lower its intensity within a range of 500%," Harutyunyan says.
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