Scientists Grow Optical Chips In A Petri Dish

The modern photonics industry is constantly working on making its devices more compact, be it computing systems or sensors and lidars. For this, it is necessary to make lasers, transistors and other elements smaller. A team of scientists led by ITMO researchers proposed a quick and affordable method to create optical chips right in a Petri dish. The research was published in ACS Nano.

Nowadays, devices that are based on microscopic lasers and optical chips are becoming more and more common. They are used in the production of lidars, in the development of new biosensors, and in the future, they can become the foundation for new optical computers that will use photons rather than electrons to transfer and process information.

Most of today’s optical chips operate in the infrared (IR) band, i.e. the lasers they use emit in the IR range that is invisible to the human eye.

Silicon issue
An optical chip consists of such components as lasers and waveguides. While creating a source that would emit in the green or red spectra is quite easy, a proper waveguide for this spectral range can be an issue.

Earlier, attempts were made to replace silicon waveguides with silver ones, but the transmission distance in such systems was also insufficient.

Optical chip in a Petri dish
In the end, a team of scientists that included specialists from ITMO University, St. Petersburg Academic University, and Université de Lorraine decided to use gallium phosphide (GaP). This material has very small losses in the visible range as well as high refractive index. The microlaser itself was made of halide perovskite. But the most important thing is that the laser was grown directly on the waveguide in a common Petri dish.

The resulting systems can transmit signals for a much greater distance than their counterparts with silicon or silver nano-waveguides. At the same time, the size of these chips is about three times less than that of its IR band analogues.

Color adjustment
Another important feature of the chip is the ability to adjust the emission range of a laser from green to red spectral range. Moreover, you can change the emission color after the chip production, and this process is reversible.

This can be useful for the devices that have to transmit many optical signals at different wavelengths. For example, you can create several lasers for such a device, connect them to a single waveguide, and use it for transmitting several signals at different wavelengths at once.

Antenna
The scientists also equipped the newly created chip with an optical nanoantenna made of perovskite that receives the signal travelling along the waveguide and allows uniting two chips in a single system.

The research was published in ACS Nano, one of the leading scientific journals.