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Laboratoire d’Excellence SEAM « Science and Engineering for Advanced Materials and devices »

Article mis en ligne le 11 décembre 2017
dernière modification le 6 septembre 2018
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A4 : Photonic devices


The sub axis " photonic devices " develops quantum devices for the emission of photons, the detection, the manipulation and the storage of photons under different regime. It contributes to the fundamental and applied research in the fields of optics, quantum physics, materials science, and semiconductor devices. Another way to functionalise materials is to change their electronic structure by creating artificial composites typically obtained by deposition of nano-metric layers that gives rise to electronic potential well. The ultimate goal is to control position and energy of individual electrons by ascribing into the matter potentials capable to control their position in the three dimensions ofthe space.

In the case of photonic devices the electronic properties are tailored to efficiently enhance the interaction between light and matter and generate light emitters, detectors and new devices that incorporate quantum mechanical effects not yet exploited by modern technologies. This research on photonic devices will produce a new generation of devices capable to transform electrons into well-defined photons and vice-versa

Quantum cascade lasers in the terahertz and mid-infrared spectral ranges for the generation of frequency combs.

The objective of this workpackage is to demonstrate the generation of frequency combs based on actively mode-locked QCLs emitting in the mid-IR and THz spectral ranges. We target a minimum spectral width of 1THz. To obtain this objective, two main challenges will need to be faced. In the mid-IR spectral range there is presently a difficulty in reaching high modulation depths, owing to a strong absorption of the microwave field inside the laser waveguide. Increasing the modulation depth is a crucial step to enable wide spectral emission. We plan to achieve high modulation depths by embedding the QCL active region in new types of waveguides, similar to the microstrip lines routinely used by microwave engineers. Ways to significantly reduce the average doping density inside the active region will also need to be found in order to reduce microwave absorption. In the THz spectral range, the main issue is related to the relatively narrow spectral gain of present QCLs. To increase the gain spectral width we will exploit the freedom given bandgap engineering in determining by design the energy of the laser transition.

For example, active regions composed of multiple stacks emitting at slightly different frequencies will be used to widen the spectral gain. Photon sources for quantum information based on micro- and nano-structured nonlinear materials. The aim is to conceive, fabricate and characterize new sources of quantum light in the telecom range following two complementary approaches. The MPQ laboratory, after the demonstration of several techniques of phase matching in semiconductor waveguides (birefringence, modal) and counter propagating phase matching) has recently demonstrated a microcavity based source of indistinguishable photons. The team now plan to demonstrate the original properties of the two photon state associated to the counter propagating geometry, such as the direct generation of polarization-entangled Bell states, the two-photon state controlled generation via the proper choice of the spatial and spectral pump beam profile, and to study more complex quantum architectures, including the integration of diode lasers and waveguide interferometers for quantum computation. The LUMEN team at LPL laboratory will work at the conception of a new heralded single photon source based on parametric down conversion in a nonlinear photonic crystal (2D PPLN) ; the team will study and compare the dispersion management and the induced quasi-phase matching performances when using 1D and 2D periodically poled nonlinear crystal and photonic crystals in LiNbO3 to perform parametric down conversion.

A special attention will be devoted to the gain management in optical parametric amplification and oscillation when using a 2D PPLN. The collaboration between the two teams will include 1D and 2D numerical modeling of micro and nanostructured nonlinear material and photon counting techniques in the telecom wavelength. Quantum well detectors for infrared thermal imaging The objective of this project is to optimize infrared detectors operating in photovoltaic mode, called Quantum Cascade Detectors (QCDs). The performance of these devices will be compared to that of Quantum Well Infrared Photodetectors (QWIPs), thanks to the collaboration with Thales Alcatel 3-5 lab, specialized in the characterization of infrared thermal imagers. In order to improve the performance of QCDs, the physics of the transport in quantum cascade structures must be studied and analyzed, both with and without illumination. The objective is to obtain for the first time a complete picture of the transport in a QCD, leading to the optimum design of a focal plane array. Following this design, devices will be produced at Alcatel Thales 3-5 lab (semiconductor growth, and thermal thermal imager array technological processing). Operation at two different wavelengths will be studied : 8 µm (this wavelength is optimum for night vision), and 16 µm (well suited for space borne observation). Operation of QCDs at both wavelengths will be compared to state of the art QWIP detectors. The first thermal image with a Quantum Cascade Detector will be demonstrated. The final objective is the demonstration of a very high performance detector in the long integration time regime. Quantum devices operating in the regime of light-matter strong coupling This project is headed by Professor Carlo Sirtori that was awarded by the ERC last year. It deals with the conception and realisation of semiconductor quantum devices that exploit the coherent superposition of two distinct states to obtain new functionalities, in particular focu on the realisation of efficient optoelectronic emitters. The rationale behind the project is that the spontaneous emission, in the THz frequency range, is characterized by an extremely long lifetime when compared to non-radiative processes, giving rise to devices with very low quantum efficiency. This issue can be overcome by developing hybrid light-matter systems, already well known in quantum optics, within optoelectronics devices, in which the material excitations are obtained by electrical injection. With this project we aim to extend the field of optoelectronics by introducing some of the concepts of quantum optics and particularly to implement novel optoelectronic emitters operating in the strong coupling regime between an intersubband excitation of a two-dimensional electron gas and a microcavity photonic mode. Few experimental results in this direction have been already obtained. Midinfrared LEDs based on intersubband polaritons, working up to room temperature, have been demonstrated. Moreover, in these devices we have been able also to observe polariton scattering with optical phonon. Finally, in the THz region we achieved the regime of ultra-strong coupling in which the Rabi frequency is comparable to the photon energy. Photosensitive oxides and hybrids for reversible laser microstructuring and Photovoltaics This work package is devoted to the controlled fabrication of photosensitive metal oxide based (TiO2, ZnO, ZrO2, etc.) organic-inorganic hybrids. We will combine two approaches based on sol-gel chemistry (see section A3), plasma chemistry and laser photochemistry in order to produce, shape and structure the bulk materials. The choice of metal oxide based hybrids is dictated by their particular electronic and related optical properties that pave the way to large-scale applications, such as laser microstructuration, photocatalysis and photovoltaics. La irradiation will be applied at different process stages in order to structure the material shape and the local properties at the nano- and micro-scale. The laser-triggered photocatalytic transformations will be used for surface functionalization. The following applications are : (1) Surface metallization of the nanostructured hybrids will address 3D-periodic conductive nanostructures that work as metamaterials, (2) the functionalization of the interface of 3D-structured hybrids by biomolecules (e.g. peptides) will address the fabrication of functional scaffolds for 3D-guided cell growth, (3) TCO assembling with silicium will address the full plasma approach for the fabrication of advanced solar cells. The proposed approach for elaboration and processing the photosensitive oxides will open new opportunities for the fabrication of advanced nanomaterials with tuneable surface and volumetric properties at the nano- and micro-scale, and to applications in photonics and biomedicine. LSPM and LPL will participate to this project.

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