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Whereas most of the reports on the nonlinear properties of micro- and nanostructures address the generation of distinct signals, such as second or third harmonic, we recently demonstrated that the novel generation of dual output lasers developed for microscopy can readily increase the accessible parameter space and enable the simultaneous excitation and detection of multiple emission orders such as several harmonics and signals stemming from various sum and difference frequency mixing processes. [1] This rich response, which in our case features 10 distinct emissions and encompasses the whole spectral range from the deep ultraviolet to the short-wave infrared region, is demonstrated using various nonlinear oxide nanomaterials while being characterized and simulated temporally and spectrally.

Optical properties and nonlinear optical response due to the CW and pulsed laser radiation self-action at 532 nm were studied in composites based on KDP single crystals with incorporated nanofibriles of nanostructured oxyhydroxide of aluminum (NOA). It was shown a high optical quality and structural homogeneity of nanocomposites KDP:NOA by the transmittance spectra, elastic optical scattering and XRD analysis. It was observed manifestation of the second harmonic generation efficiency enhancement in the KDP:NOA versus the nominally pure KDP ( λ =1064 nm, τ =1 ns) that is correlated with efficient refractive index self-modulation Δ n ∼ 10 − 4 ( λ =532 nm, τ =30 ps). In the pyramidal and prismatic growth sectors of the nominally pure KDP crystal it was shown opposite signs of the photoinduced variations both of the refractive index and of the optical absorption/bleaching due to resonant excitation of the native defects at 532 nm. It should be considered for the wide-aperture laser frequency KDP family based convertors fabrication.

International audience; SiC nanoparticles by carbothermal reduction show promising properties in terms of second harmonic and multiphoton excited luminescence. In particular, we estimate a nonlinear efficiency < d > = 17 pm/V, as obtained by Hyper Rayleigh Scattering. We also present results of cell labelling to demonstrate the potential use of SiC nanoparticles for nonlinear bioimaging by simultaneous detection of second harmonic and luminescence.

International audience; We have investigated nanocrystals of Fe(IO3)3 by polarization-sensitive second harmonic generation (SHG) microscopy. As the nonlinear optical properties of this material were only poorly characterized, we have first determined the relative values of the elements of its second-order susceptibility tensor, by the global fitting of the polarization-resolved SHG response of an ensemble of nanocrystals. This information allows one to optically retrieve the orientation of individual particles in the sample. The high SHG efficiency measured for nanocrystals of Fe(IO3)3 and their polar nature could make them very attractive for nonlinear microscopy of biological samples.

International audience; A Laponite clay-based lithium iodate nanocomposite has been synthesized for non-linear optical applications. The surface morphology of dip-coated optical waveguides were analysed by Scanning Force Microscopy (SFM) techniques. Individual Laponite particles were first imaged by using Intermittent-Contact Atomic Force Microscopy on pure Laponite layers. Electrostatic Force Microscopy was then used on nanocomposite waveguides in order to obtain a "chemical contrast" of sample surface. The strong electrical contrast observed was attributed to sample topography and not to the different properties of each nanocomposite constituent. Finally, in ambient conditions, dip-coated layers were also shown to be sensitive to humidity which leads to the occurrence of surface lithium iodate crystals with sub-micrometer size.

A new clay-based nanocomposite has been developed for non-linear optical waveguiding applications. Thin layers are deposited on glass substrates by using dip coating technique from an aqueous solution made of a Laponite suspension mixed with a lithium iodate (LiIO3) aqueous solution. Transparent layers with waveguiding properties are obtained with an effective non-linear coefficient of about 1.4 pm/V for a 55% vol. LiIO3 composite. Control of nanocrystals orientation has been performed by applying an electric field with Corona discharge or deposited gold electrodes. Characterisation of nanocrystals orientation was done by Second Harmonic Generation (SHG) measurements and polarised light optical microscopy.

Using deep level transient spectroscopy and photocurrent measurements we have investigated Schottky contacts formed on p-isotype Zn(SSe)/GaAs heterostructures grown by molecular beam epitaxy on p-GaAs(100) substrates. A deep level located at 0.6 eV above the ZnSe valence band is observed in agreement with literature data for p-type ZnSe, and is used as a reference level for the understanding of photocurrent transitions in the 0.8–3.0 eV energy range. The threshold energies obtained on a series of Zn(SSe)/GaAs samples are explained in terms of absorption processes from the ZnSe and GaAs valence bands, and from the nitrogen acceptor level and a deep level of the ZnSe layers located at 0.1 and 0.6 eV above the valence band maximum, respectively. These absorption processes towards the ZnSe and GaAs conduction bands have been finally used to give the values of the conduction and valence band offsets at p-ZnSe/p-GaAs interface. Our experimental data gives ΔEc=0.25±0.03 eV and ΔEv=1.00±0.05 eV in agreement with ...

A tunable Fabry–Perot filter based on InP/air Bragg mirrors has been studied. We have measured a resonance linewidth of 0.6 nm and a tuning range of 62 nm. The linewidth is kept below 1 nm over a 40 nm tuning range. The relation between the bending of the suspended layers during the actuation and the optical properties of the filter are analysed.

A tunable Fabry-Perot filter based on InP-air Bragg mirrors has been studied. The filter experimental performances are a resonance line width of 0.6 nm and a tuning range of 62 nm for 14 V. The full-width at half-maximum is kept below 1 nm over a 40-nm tuning range. The relation between the bending of the suspended layers during the actuation and the optical properties of the filter are analyzed.

The ability of pellets made up of compressed iron iodate nanocrystals to frequency-double the whole visible spectrum is demonstrated. We suggest their use for complete characterization of intense ultrabroadband laser pulses.

The paper reports on the investigation of the nonlinear optical properties of nanosized grains of Fe(IO3)3, recently synthesized with a simple and inexpensive process. The measurements have been carried out using a Ti:sapphire femtosecond oscillator coupled to an inverse microscope modified to detect the polarization dependence of the signal. It is shown that Fe(IO3)3 crystals (20-70 nm) can be efficiently employed as local probes for second-harmonic generation (SHG) microscopy, owing to their high nonlinear coefficients.