Researchers at MIT have for the first item created a diamond-based quantum sensor on a silicon chip. The team thinks that the advance in fabrication could open the door for low-cost, scalable hardware for quantum computing, sensing, and communication. The breakthrough leverages something called “nitrogen-vacancy (NV) centers.”
An NV center in diamonds are defects with electrons that can be manipulated by light and microwaves. In response to that manipulation, they emit colored photos that can carry quantum information about surrounding magnetic and electric fields. That data can be used for biosensing, neuroimaging, object detection, and other sensing applications.
The team notes that traditional NV sensors are about the size of a kitchen table. They also require other large components that limit practicality and scalability. The MIT team has figured out how to integrate all of the bulky components, including the microwave generator, optical filter, and photodetector onto a millimeter-scale package using traditional semiconductor fabrication techniques.
The sensor operates at room temperature and can sense direction and the magnitude of magnetic fields. The team was able to use the sensors for magnetometry measuring atomic-scale shifts in frequency. That data could contain information about the environment. Researchers say that with more refinement, the sensor could have a range of other applications including mapping electrical impulses in the brain and detecting objects without a line of sight.
One example of detecting objects you can’t see physically is being able to detect a vehicle moving in an underground tunnel without seeing it. The MIT creation is an architecture that stacks tiny, inexpensive components in a certain way using standard CMOS technology. The team says their complete system on a chip needs only a piece of diamond and a green light source, which can be a chip-scale LED.