In contrast with conventional light-emitting diodes (LEDs) that emit billions of photons simultaneously to form a steady stream of light, a single photon emitter (SPE) generates exactly one photon on demand, with each photon indistinguishable from another. These characteristics are essential for photon-based quantum technologies under development. In addition, such capabilities should be realized in a material platform that enables precise, repeatable placement of SPEs in a fully scalable fashion compatible with existing semiconductor chip manufacturing.
Researchers developed a way to directly write quantum light sources — which emit a single photon of light at a time — into monolayer semiconductors such as tungsten diselenide (WSe2). An atomic force microscope (AFM) was used to create nanoscale depressions or indents in a single monolayer of WSe2 on a polymer film substrate. A highly localized strain field is produced around the nano-indent, creating the single photon emitter state in the WSe2. Time-correlated measurements of this light emission confirmed the true single photon nature of these states. These emitters are bright, producing high rates of single photons, and spectrally stable — key requirements for emerging applications.
This quantum calligraphy allows deterministic placement and real-time design of arbitrary patterns of SPEs for facile coupling with photonic waveguides, cavities, and plasmonic structures. A nano-imprinting approach is effective in creating large arrays or patterns of quantum emitters for wafer-scale manufacturing of quantum photonic systems.
In addition to enabling versatile placement of SPEs, these results present a general methodology for imparting strain into two-dimensional (2D) materials with nanometer-scale precision, providing an invaluable tool for further investigations and future applications of strain engineering of 2D devices.
Quantum computation on a chip provides onboard capability to rapidly analyze very large data sets acquired by sensor arrays, so that the entire data set does not have to be transmitted, reducing bandwidth requirements.