Camera Based On A CMOS And Quantum Dots

Engineers has developed a Low-Cost Terahertz Camera Using Quantum Dots. This camera is based on widely available complementary metal oxide semiconductors (CMOS), enhanced using quantum dots. Quantum dots are nm size semiconductor particles with advantageous optoelectronic properties.

The new terahertz camera device provides greater sensitivity and speed than previous versions. It can be use for industrial inspection, airport security, and communications.

For instance, THz detectors could allow law enforcement agents to uncover potential weapons on humans or in luggage more reliably. It can also be use to monitor natural environments without damaging them or to assess the quality of food, cosmetics and other products.

Figure Credit: Courtesy of the researchers. It shows terahertz illumination entering the new camera system. Yellow curves at top right where it stimulates quantum dots inside nanoscale holes (shown as illuminated rings) to emit visible light. Then, it detects using a CMOS-based chip (bottom left) like those in digital cameras.

Breakthrough

Prior, Nelson and his colleagues found that an electron’s return to its original hosting quantum dot is typically accompanied by the emission of visible light. In their new study, they set out to create a device that would leverage the process they observed and the resulting light emission to detect THz pulses.

The CMOS based THz camera created by the researcher was assembled in two separate stages. First, Nelson, Oh, Shi and their colleagues fabricated nanoscale field enhancement structures. The structures were created using electron beam lithograph.

The second stage of the camera’s assembly entailed the synthesis of quantum dots and their deposition onto the field enhancement structures.

Enhancement structure is a pattern conducting layers with sub-micron insulating gaps in which an incident THz field is strongly enhance.

Camera in initial evaluations achieved remarkable results. The device is also affordable and can be scaled up to wafer size for large area imaging or other large scale applications.

The camera created by Nelson, Oh and Shi can simultaneously detect both the intensity of THz light and its polarization states.

In the future, it could thus open new exciting possibilities for the sensing and characterization of THz light.

Also read: Physicist Awarded Noble Prize In Quantum Physics