A Wirelessly Controllable Optoelectronic Device for Optogenetics

The purpose of this letter is to report a new optoelectronic device which consists of a wirelessly controllable driver circuitry and a slender implantable optical probe. Instead of the conventional silicon substrate, the probe is based on GaN material growing on a sapphire substrate. Thin-film blue micro light-emitting diodes ( $\mu $ LEDs) with a total optical power density of 176.9 mW/mm 2 at 1 mA are directly fabricated at the probe by semiconductor device fabrication technologies. In a further research, we integrate a yellow $\mu $ LED on the probe to enable optical stimulation of both excitatory and inhibitory neurons. Besides, we adopt Bluetooth 4.0 wireless communication protocol; therefore, light emitting from the $\mu $ LEDs can be remotely controlled by a terminal with a distance as far as 20 m. The driver is also equipped with an accelerometer, a power management module, and a system-on-chip (SoC), and they are energized by a rechargeable lithium battery that has up to 10-h battery life. The whole device is a little bit bigger than a coin and weighs approximately 6 g. The probe has a length of 1.65 cm and a thickness of $150~\mu \text{m}$ . These features make the device suitable for a broad variety of optogenetic experiments.