A new paradigm for quantum emitter control – modulating and encoding quantum photonic information on a single optical stream
A multidisciplinary team at the U.S. Naval Research Laboratory (NRL) has developed a new paradigm for controlling quantum emitters, providing a new way to modulate and encode quantum photon information in single-photon light streams.
Quantum photonics is expected to provide capabilities not possible with classical light, and promises significant advances in secure communications, metrology, sensing, and quantum information processing and computation.
These applications place many requirements on quantum emitter (QE) candidates. This includes deterministic creation and placement of emitters, high single-photon purity in the range of 90-100%, and mechanisms to control or modulate such emission.
The ability to modulate the properties of the light emitted from these discrete emitters provides a mechanism to encode information on a single photon stream, with applications in secure communications and quantum cryptography schemes based on single-photon sources. . This research was recently published in ACS Nano.
Quantum photonics is a science and technology that uses quantum optics for specific applications where quantum effects play an important role. This involves producing, manipulating, and detecting light in regions where individual quanta of the light field can be consistently controlled. QE, also known as single photon emitter, is a key component of this technology.
“Two-dimensional materials such as single-layer tungsten disulfide and tungsten diselenide can serve as hosts for QE, and their planar atomic layer structure offers many advantages as material platforms for quantum photonic circuits.” , said NRL Senior Scientist, Dr. Berend Jonker. Principal researcher. “They can be easily integrated with other materials and substrates, and the closeness of the QE to the surface facilitates both light extraction and control of emission by external effects.”
NRL team has developed a nonvolatile and reversible procedure to control the single-photon emission purity of single-layer tungsten disulfide (WS2) by integrating it with ferroelectric materials . By creating an emitter within WS2 and switching the ferroelectric polarization with a bias voltage, they can switch the emission between high-purity quantum light and semiclassical light. Localized emitters in the monolayer WS2 on the “up domain” of the ferroelectric film emit high-purity quantum light, and localized emitters on the “down domain” emit semiclassical light.
“This new heterostructure introduces a new paradigm for quantum emitter control by combining the nonvolatile ferroic properties of ferroelectrics with the radiative properties of zero-dimensional atomic-scale emitters embedded in a two-dimensional WS2 semiconductor monolayer. ” Jonker said.
The studied sample consists of a monolayer film of WS2 grown by chemical vapor deposition and mechanically applied onto a 260 nanometer film of organic ferroelectric polymer previously transferred onto a heavily doped silicon substrate. transcribed into. Scientists used NRL-developed and patented atomic force microscopy (AFM) nanoindentation technology to deterministically create quantum emitters and place them within WS2.
“It is extremely important to have close contact between the WS2 and the ferroelectric film, and an ultra-smooth ferroelectric film surface is required,” said Professor Jonker of the American Society for Engineering Education (ASEE), who is collaborating with Jonker on the research. said Dr. Sungeon Lee, a postdoctoral researcher. “Therefore, a spin-coating and inversion process was used for the film.”
“Organic ferroelectric polymers act as deformable polymers,” said Dr. Ben Chuan. Research physicist in the NRL Materials Science and Technology Division. “When the AFM tip is removed, WS2 conforms to the contour of the nanoindentation, and the local strain field activates single-photon emission from atomic-scale defect states within WS2.”
Next, for the top electrical contact, we transferred graphite to partially cover WS2 and applied a bias voltage using a conductive piezoelectric microscope tip to switch the polarization of the ferroelectric polymer below WS2. Ta.
The NRL research team consisted of postdoctoral researcher Dr. Sungjoon Lee; Hsun-jen Chuang, PhD, research physicist. Dr. Kathy McCreary, Research Physicist; Dr. Dante O’Hara, Materials Engineer. Dr. Berend Jonker, Senior Scientist. Everyone in the NRL Materials S&T department. Dr. Andrew Yates, Research Physicist in the NRL Electronics Science and Technology Division.
Further information: Sung-Joon Lee et al., Ferroelectric modulation of quantum emitters in single-layer WS2, ACS Nano (2024). DOI: 10.1021/acsnano.4c10528
Provided by Naval Research Institute
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