Silicon touts strength in photonic informational manipulation

The power of silicon could soon change the photonics game, potentially offering new opportunities for producing lasers and displays. Currently, there is no commercially available silicon for such technology or for light-emitting diodes.

An international research team, led by the University of Surrey (Guildford, England), has discovered that silicon may be “one of the most powerful materials for photonic informational manipulation.” Essentially, it is “an outstanding candidate for creating a device that can control multiple light beams.” It’s now possible to produce silicon processors featuring built-in abilities for light beams to control other light beams. This could ultimately boost the speed and efficiency of electronic communications.

Such development is possible in the far-infrared (far-IR) region of the electromagnetic spectrum by taking advantage of the nonlinear optical properties of silicon. The researchers note that silicon’s third-order nonlinearity can be used to produce an output beam with a third of the wavelength, or redirect a laser beam to control the direction of the beam’s information. Third-order nonlinearities are important, the study notes, as they allow control over light pulses in ever-present centro-symmetric materials such as silicon and silica. “The stronger the nonlinearity,” the team says, “the easier it is to control with weaker input beams.”

The study was done by cooling crystal to very low cryogenic temperatures—strong nonlinearities mean that extremely weak beams can be used. Ben Murdin, a professor of physics at Surrey and co-author of the study, notes the team’s discoveries were made as they worked to understand how a very small number of phosphorus atoms in a silicon crystal could be used for making a quantum computer. They also were looking at ways to use light beams to control quantum information.

The researchers showed that silicon’s nonlinearity makes it an ideal candidate for development of devices that control multiple light beams via four-wave mixing. Reference: N. Dessmann et al., Light Sci. Appl. (2021); doi.org/10.1038/s41377-021-00509-6.