By Prof Ronen Rapaport
Ronen Rapaport, HUJI, Faculty of Science, The Racah Institute of Physics
Uri Banin, HUJI, Faculty of Science, The Center for Nanoscience and Nanotechnology
Yossi Paltiel, HUJI, School of Computer Science and Engineering, Applied Physics
Shira Yochelis, HUJI, Faculty of Science, Applied Physics Department
Very minute photonic devices need small optical elements that can manipulate light even at the single photon level. There is also a need for small active elements for absorption and emission of photons and a way to control this light locally on an identical sub-wavelength scale. Nanocrystal quantum dots (NQDs) are utilized as sources of single photon emissions and symbolize the building blocks for optical quantum data devices as well as multi-photon sources for several other classical light applications such as biology, displays etc.
Existing techniques for harvesting and extracting photons from quantum dots are normally not well controlled and it is not easy to control the timing and directionality of the emitted photons.
This research is of interst to micro & opto electronics, nanotechnology and photonics.
This research is at the proof of concept stage and a patent application has been filed in the US.
The researchers have discovered a technique to embed nanocrystal quantum dots in a sub-wavelength metallic nanoslit array to obtain highly directional emission and beaming of photons.
The key features of this technology are listed below:
- The emission probability of a quantum dot into the narrow angular mode is increased considerably when compared to the emission probability to all other modes.
- Spatial control of the optical properties of nanoemitters is provided at both the single and the multiple photon level.
The applications for this technology are listed below:
- This technology can be utilized for any application where the direction of emitted light is significant. This means that whenever the source receives light from a specific direction, it will respond by emitting photons in the same direction only. It is highly sensitive to the environmental index of refraction, therefore can sense even very small changes in composition of solutions such as various biological and chemical solutions.
- Bio-chemical sensing
- Laser targets for military, security, and civilian applications
The researchers are seeking funding to continue the research in order to improve the technique for single and multiple photon sources.
About Racah Institute of Physics
The Racah Institute of Physics at the Hebrew University of Jerusalem is home to advanced physics research encompassing a broad range of physics disciplines from biophysics, non-linear physics, nanophysics and condensed matter physics, to few body systems, high energy and astrophysics and nuclear & hardonic physics. It also caters to a large number of students at all levels, from a high level undergraduate curriculum to advanced graduate degrees, as can be attested by a Racah Institute of Physics graduate and Nobel laureate, Prof. David Gross.