The new class of quantum dots delivers a stable flux of single, spectrally adjustable infrared photons in ambient conditions and at room temperature, unlike other single photon emitters. This discovery opens up a number of practical applications, including quantum communication, quantum metrology, medical imaging and diagnostics, and secret labeling.
“Demonstrating the high purity of a single photon in infrared radiation has immediate benefits in areas such as quantum key distribution for secure communication,” said Victor Klimov, lead author of a paper published today in Nanotechnology of nature a scientist from the Los Alamos National Laboratory.
The Los Alamos team developed an elegant approach to the synthesis of colloidal nanoparticle structures derived from their previous work on visible light emitters based on a cadmium selenide nucleus wrapped in a cadmium sulfide shell. By inserting a mercury sulfide interlayer into the core / shell interface, the team converted quantum dots into highly efficient infrared light emitters that can be tuned to a specific wavelength.
“This new synthesis allows very precise control over the thickness of the mercury sulfide radiation layer emitting mercury sulfide. By changing the steps of each atomic layer, we can adjust the wavelength of light emitted in discrete quantized jumps and further adjust it more continuously by adjusting the cadmium selenide core size.” said Vladimir Sayevich, the lead chemist on this project.
Far superior to existing close infrared quantum dots, these new structures show “no flicker” emission at the single point level, near-perfect purity of one photon at room temperature (which produces “quantum light”), and fast emissions. They behave extremely well with both optical and electrical excitation.
Individual photons can be used as qubits in quantum computation. In a cyber security application, individual photons can protect a computer network by distributing quantum keys, providing ultimate security through “unbreakable” quantum protocols.
Bio-image is another important application. The emission wavelength of the newly developed quantum dots is located near the infrared bio-transparency window, which makes them suitable for deep tissue imaging.
Humans cannot see infrared light, but many modern technologies rely on it, from night vision devices and remote sensing to telecommunications and biomedical imaging. Infrared light is also a big player in new quantum technologies that rely on the duality of light particles or photons, which can also act as waves. To exploit this quantum property, “quantum light” sources that emit light in the form of individual quanta or photons are needed.
“There’s also a cool chemical element in achieving precision of the monoatomic layer in creating these points,” said Zack Robinson, a member of the project that focuses on quantum dot spectroscopy. “The thickness of the mercury sulphide emitting interlayer is identical at all points in the samples. This is very unique, especially for material that is chemically made in a beaker.”
Klimov added, “However, this is only the first step. In order to take full advantage of ‘quantum light’, photon indistinguishability must be achieved, ie ensure that all emitted photons are quantum-mechanically identical. This is an extremely difficult task that we will solve next in our project. ”
Scientists are creating a new device that will light the way for quantum technologies
Vladimir Sayevich, et al., Very versatile near-infrared emitters based on an atomically defined HgS interlayer embedded in a CdSe / CdS quantum dot, Nanotechnology of nature. DOI: 10.1038 / s41565-021-00871-x
Provided by the Los Alamos National Laboratory
Citation: A new class of versatile high-performance quantum dots prepared for medical imaging, quantum computing (2021, March 25) retrieved March 25, 2021 from https://phys.org/news/2021-03-class-versatile-high-performance -quantum-dots.html
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