Sujet de TPE PROPOSITION

Transcription

1 Single photon source made of single nanodiamonds This project will consist in studying nanodiamonds as single photon sources. The student will study the emission properties of such systems and will show that they are indeed single photon sources. Optical spectroscopy and photon correlation will be the 2 main techniques involved here. The nanodiamonds will be commercially available but will have to be processes and studied during this project. nanodiamonds. Photon statistics and photon correlation will then be studied in order to understand the quantum optical properties of the nanostructures.

2 Life-time studies of ZnO and hybrid ZnO-based nanostructures. This project will consist in studying lifetime measurements of nanostructures made of ZnO and hybrid ZnO-based materials. Study of carriers decay times in semiconductors such as ZnO is of prime importance in order to address different applications such as photovoltaic, lighting or sensing applications. The student will study the emission properties of such systems and optical spectroscopy and photon correlation will be the two main techniques involved here. ZnO nanostructures (mainly nanowires but not only) will be available through our various collaborations (GEMaC from Versailles University and start-up Nanovation) but also from our own group done by Chemical Bath Deposition (CBD) growth. nanostructures. Photon statistics and photon correlation will then be studied in order to understand the decay properties of the nanostructures. Key words: Lifetime, optical spectroscopy, photoluminescence, fluorescence correlation spectroscopy

3 Responsables * : Christophe Couteau, Rafael Salas-Montiel Coupling single nanostructures to plasmonic waveguides This project will consist in coupling single nanostructures to plasmonic waveguides. The nanostructures will be of various forms such as ZnO nanowires, CdSe nanocrystals and nanodiamonds. The goal of this project is to study the light-matter interaction between a single nanostructure and a plasmonic waveguide. The new field called quantum plasmonics has a great potential in sensing and quantum information for instance. nanostructures. Photon statistics and photon correlation will then be studied in order to understand the quantum optical properties of the nanostructures. Waveguide fabrication by e-beam lithography might be necessary depending on the structures already available. Key words: quantum optics, plasmonics, waveguiding, fluorescence correlation spectroscopy, light-matter interaction

4 Microphotoluminescence of nanostructures The goal of this project is to use a home-made microphotoluminescence set-up in order to address optically individual nanostructures such as nanowires but also nanocrystals. Semiconductor spectroscopy will then be studied for these structures as well power and polarization dependence. Microphotoluminescence is a technique that allows the excitation of micro-size areas in order to confine the excitation. By the same token, the luminescence is collected on a same micro-size region of the sample. By this mean the student will study the light-matter interaction at the nanoscale for future applications in sensing, photovoltaic and quantum information.

5 Nanowire-based photodetector with high gain The goal of this project is to study the photoconductive gain of semiconductor nanowires. Recently, such nanostructures have come across as being very good photodetectors with an important gain (current/light conversion) and could be as efficient as the state of the art commercial detectors. Nevertheless, the true measurement of this photoconductive gain remains unknown and the purpose of this project is to address 2 issues: 1) to use a single photon source for accessing the intrinsic gain of a single semiconductor nanowire and 2) to channel the light efficiently towards the nanowire for efficient detection. The methods used in this project will be: setting-up a microphotoluminescence experiment at room and low temperatures, contacting and fabricating metallic slots for the plasmonic waveguide and finally measure the gain upon illumination with a faint laser source and a single photon source. The results and perspectives for this project are a better knowledge of light-matter interaction at nanometer scales as well as a better understanding of the physical phenomena responsible for the high internal photoconductive gain in semiconductor nanowires. This project is mostly experimental although some simulation will be done too.