Aspects of hole-burning and spectro-temporal holography in molecular doped solids (Review Article)

The persistent spectral hole-burning (PSHB) phenomenon is known since 1974. It is still an important research area for the study of the intimacy of complex molecular systems in the solid state, revealing high resolution spectra, photophysics, photochemistry and dynamics of molecular doped amorphous media, organic as well as inorganic. From another point of view, PSHB allows the engraving of any spectral structures in the inhomogeneous absorption band profile of molecular doped amorphous hosts or ion doped crystals cooled down to liquid helium temperatures. Therefore, a PSHB material is programmable in the spectral domain and consequently it can be transformed in an optical processor capable to achieve user-defined optical functions. Some aspects of both fields are illustrated in the present paper. Concerning the search of efficient PSHB materials, the hole burning performances and the photophysics of polymer and xerogel based systems are compared. The problem of high-temperature persistent spectral hole-burning materials and the search for new frequency selective photosensitive systems for fast optical pulse processing at 800 nm are considered. Regarding the points treated, inorganic hosts based on silicate xerogels or porous glasses have shown the best results. Moreover, by combining inorganic and organic capabilities or by grafting organic species to the host, hybrid xerogels have not yet revealed all possibilities. Also, the interest of two-photon materials for engraving spectral features with near-infrared or infrared light is developed. As an introduction to possible applications of PSHB material, the basics of spectro-temporal holography are remembered and a demonstrative experiment using a naphthalocyanine doped polymer film is described, proving that the temporal aberration free re-compression of ultrashort light pulses is feasible, therefore opening a way for applications in ultrashort light pulse shaping. Aspects for a comparison between cw hole-burning and femtosecond spectro-temporal experiments are considered and perspectives for the coherent control of light fields or photochemical processes are also evoked

A Method to Design a Multi-Player Educational Scenario to Make Interdisciplinary Teams Experiment Risk Management Situation in a Digital Collaborative Learning Game: A Case of Study in Healthcare

In recent years, there has been an increasing interest for collaborative training in risk management. One of the critical point is to create educational and entirely controlled training environments that support industrial companies (in aviation, healthcare, nuclear…) or hospitals to train (future or not) professionals. The aim is to improve their teamwork performance making them understand the importance applying or adjusting safety recommendations. In this article, we present a method to design multi-player educational scenario for risk management in a socio-technical and dynamic context. The socio-technical situations focused in this article involve non-technical skills such as teamwork, communication, leadership, decision-making and situation awareness. The method presented here has been used to design as well regular situations as well as critical situations in which deficiencies already exist or mistakes can be freely made and fixed by the team in a controlled digital environment

Photolithographic processing of silver loaded dielectric coatings based on preformed colloidal TiO2nanoparticles dispersed in a mesoporous silica binder

Titanium dioxide is a well known photocatalyst for reactions involving surface trapped photogenerated carriers. Noble metal photo-reduction may be used for the processing of silver/TiO 2 nanocomposite coatings that may exhibit interesting optical and electrical properties. We present here results of our investigations performed on an original system consisting of preformed colloidal TiO 2 nanoparticles homogeneously dispersed within a mesoporous silica host matrix. Light irradiation of samples immerged in an aqueous silver salt solution leads to the homogeneous deposition of silver islands in the vicinity of the TiO 2 particles and throughout the film thickness. The silver volume fraction is directly controlled by the irradiation dose up to a value of about 16 vol.%. Films exhibit tunable plasmonic properties that correspond to silver nanoparticles in interaction, and a percolation threshold is observed at 8–10 vol.%, leading to films with a conductivity of about 40 S cm −1 . The major interest of this method lies in the high silver reduction quantum efficiency (about 50%) and the possibility to modulate optical and electronic properties by light irradiation while the low temperature of processing permits the photolithographic deposition of metallic patterns on organic flexible substrates

Réalisation de pinces optiques pour la manipulation de nano et micro objets individuels d'intérêt chimique ou biologique

Nous avons construit une expérience de pinces optiques basée sur l'utilisation d'un microscope optique inversé. Deux classes de micro objets ont été étudiées : 1 - Des particules colloïdales sphériques ou approximativement sphériques, soit homogènes tels des colloïdes de silice pure élabores par méthode sol-gel ou des billes commerciales de latex, soit inhomogènes tels des particules composites constituées d'un coeur métallique d'or entouré d'une coquille de silice. 2 - Des micro-monocristaux d'une molécule organique fluorescente présentant une forme non sphérique, parallélépipédique. Notre étude a démontré un piégeage efficace même sur les plus petites particules contenant un noyau d'or. Pour les nanoparticules hybrides d'or-silice, la constante élastique du piège optique expérimentalement mesurée est plus forte que pour les nanoparticules de silice avec un diamètre semblable. Ce résultat est en accord avec un modèle simple fondé sur l'accroissement de la polarisabilité de la particule dû à la présence du noyau d'or. L'influence de la polarisation de la lumière a été étudiée et nous avons discuté le choix du détecteur de position. Les microcristaux organiques s'orientent de sorte que leur axe long soit dans la direction axiale du faisceau de piégeage, l'axe court suit la direction de la polarisation linéaire du faisceau. En polarisation circulaire ou elliptique, les cristaux se mettent spontanément en rotation avec des vitesses de rotation tout à fait élevées, jusqu'à 500 tours par seconde. C'est la première fois qu'un tel résultat est reporté pour des particules de la taille de nos cristaux. Un autre résultat surprenant est que lorsque la puissance incidente augmente, la vitesse de rotation augmente aussi comme attendu mais après passage par un maximum, alors que la puissance continue de croître, la vitesse de rotation diminue jusqu'à arrêt complet de la rotation, et cette évolution n'est pas réversible ! La thèse présentée est une thèse réalisée dans un cadre de cotutelle entre l'Université Paris 11 et l'Institut Supérieur des Sciences et Techniques Avancées - Université de La Havane à Cuba.We built an experiment of optical tweezers based on the use of an inverted optical microscope. Two classes of micro objects were studied : 1 - spherical or roughly spherical colloidal particles, either homogeneous such as colloids of pure silica elaborated through a sol-gel method or commercial latex balls, or inhomogeneous such as composite particles made up of a metal gold core embedded in a silica shell. 2 - micro-single crystals of a fluorescent organic molecule presenting a nonspherical, parallelepipedic form. Our study showed an effective trapping even on the smallest particles containing a gold core. For the hybrid gold-silica nanoparticles, the elastic constant of the optical trap measured in experiments is stronger than for the silica nanoparticles with a similar diameter. This result is in agreement with a simple model based on the increase in polarizability of the particle due to the presence of the gold core. The influence of the polarization of the light was studied and we discussed the choice of the detector of position. The organic microcrystals are directed so that their long axis is in the axial direction of the trapping beam; the short axis follows the direction of the linear polarization of the beam. In circular or elliptic polarization, the crystals are put spontaneously in rotation with high speed up to 500 turns per second. It is the rst time that such a result is deferred for particles of the size of our crystals. Another surprising result is that when the incident power increases, the rotation speed also increases as expected but after the passage by a maximum, whereas the power continues growing, the rotation speed decreases until complete stop of rotation, and this evolution is not reversible ! The thesis presented is a thesis carried out within a framework of cotutelle between the University Paris 11 and the Higher Institute of Science and Advanced Technologies - Havana University in Cuba.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

A Method to Design a Multi-Player Educational Scenario to Make Interdisciplinary Teams Experiment Risk Management Situation in a Digital Collaborative Learning Game: A Case of Study in Healthcare

In recent years, there has been an increasing interest for collaborative training in risk management. One of the critical point is to create educational and entirely controlled training environments that support industrial companies (in aviation, healthcare, nuclear…) or hospitals to train (future or not) professionals. The aim is to improve their teamwork performance making them understand the importance applying or adjusting safety recommendations. In this article, we present a method to design multi-player educational scenario for risk management in a socio-technical and dynamic context. The socio-technical situations focused in this article involve non-technical skills such as teamwork, communication, leadership, decision-making and situation awareness. The method presented here has been used to design as well regular situations as well as critical situations in which deficiencies already exist or mistakes can be freely made and fixed by the team in a controlled digital environment

Amplitude and phase measurements of femtosecond pulses shaped using spectral hole burning in free-base naphthalocyanine-doped films.

International audienceIn this work we use a technique of spectroscopy adapted for measuring the amplitude and phase of photon echo signals [7] produced by diffraction of a fs pulse on a spectral hologram. We also improved the technique in terms of spectral resolution in order to measure photon echoes delayed by a few tens of picoseconds. Our study is focused on measuring the coherence time of the sample using a photon echo experiment in the photochemically accumulated regime and on demonstrating the pulse-shaping and time-reversal potentialities of our photo-sensitive material. Spectral holograms are formed through persistent spectral hole burning using a sequence of 2 pump pulses separated by a time delay, in a collinear geometry. The sample is a free base naphtalocyanine embedded in polyvinylbutyral (H2NPc/PVB). The absorption peaks at 783 nm and is 20 nm large (FWHM). Our laser source is a 15-fs, 100MHz, Ti:S oscillator

Amplitude and phase measurements of femtosecond pulses shaped using spectral hole burning in free-base naphthalocyanine-doped films.

In this work we use a technique of spectroscopy adapted for measuring the amplitude and phase of photon echo signals [7] produced by diffraction of a fs pulse on a spectral hologram. We also improved the technique in terms of spectral resolution in order to measure photon echoes delayed by a few tens of picoseconds. Our study is focused on measuring the coherence time of the sample using a photon echo experiment in the photochemically accumulated regime and on demonstrating the pulse-shaping and time-reversal potentialities of our photo-sensitive material. Spectral holograms are formed through persistent spectral hole burning using a sequence of 2 pump pulses separated by a time delay, in a collinear geometry. The sample is a free base naphtalocyanine embedded in polyvinylbutyral (H2NPc/PVB). The absorption peaks at 783 nm and is 20 nm large (FWHM). Our laser source is a 15-fs, 100MHz, Ti:S oscillator

Amplitude and phase measurements of femtosecond pulses shaped using spectral hole burning in free-base naphthalocyanine-doped films.

In this work we use a technique of spectroscopy adapted for measuring the amplitude and phase of photon echo signals [7] produced by diffraction of a fs pulse on a spectral hologram. We also improved the technique in terms of spectral resolution in order to measure photon echoes delayed by a few tens of picoseconds. Our study is focused on measuring the coherence time of the sample using a photon echo experiment in the photochemically accumulated regime and on demonstrating the pulse-shaping and time-reversal potentialities of our photo-sensitive material. Spectral holograms are formed through persistent spectral hole burning using a sequence of 2 pump pulses separated by a time delay, in a collinear geometry. The sample is a free base naphtalocyanine embedded in polyvinylbutyral (H2NPc/PVB). The absorption peaks at 783 nm and is 20 nm large (FWHM). Our laser source is a 15-fs, 100MHz, Ti:S oscillator

Amplitude and phase measurements of femtosecond pulses shaped using spectral hole burning in free-base naphthalocyanine-doped films.

In this work we use a technique of spectroscopy adapted for measuring the amplitude and phase of photon echo signals [7] produced by diffraction of a fs pulse on a spectral hologram. We also improved the technique in terms of spectral resolution in order to measure photon echoes delayed by a few tens of picoseconds. Our study is focused on measuring the coherence time of the sample using a photon echo experiment in the photochemically accumulated regime and on demonstrating the pulse-shaping and time-reversal potentialities of our photo-sensitive material. Spectral holograms are formed through persistent spectral hole burning using a sequence of 2 pump pulses separated by a time delay, in a collinear geometry. The sample is a free base naphtalocyanine embedded in polyvinylbutyral (H2NPc/PVB). The absorption peaks at 783 nm and is 20 nm large (FWHM). Our laser source is a 15-fs, 100MHz, Ti:S oscillator