Les nanostructures ont montré leur utilité dans diverses applications optiques. Notre intérêt s'est porté sur deux d'entre elles : le filtrage spectral et la spectroscopie d'absorption. Dans le premier cas, l'application est notamment limitée par la réjection hors de la bande passante des nanostructures filtrantes.Dans cette thèse, j'ai étudié et développé une structure membranaire composée de deux réseaux métalliques sublongueur d'onde encapsulés dans un diélectrique. Cette structure présente une extinction aux hautes longueurs d'onde qui permet d'améliorer la réjection du filtre. Un procédé de fabrication a été développé, et les caractérisations optiques ont permis de mettre en évidence expérimentalement la présence de l'extinction de la transmission.Dans le second cas, les nanoantennes classiquement utilisées nécessitent une optimisation de la structure pour chaque liaison observée et limitent le type de molécules détectables. J'ai proposé une nouvelle méthode de spectroscopie d'absorption de molécules basée sur des nanogrilles. Ces structures composées d'un réseau de barreaux diélectriques suspendus présentent une réflexion parfaite perturbée par la présence de molécules autour de ces barreaux. J'ai montré théoriquement le potentiel de cette méthode basée sur le balayage spectral de la réflexion résonante grâce à l'angle d'incidence et je l'ai comparée aux nanoantennes métalliques décrites dans la littérature.J'ai ensuite fabriqué et caractérisé des nanogrilles de deux sections différentes et montré l'impact de paramètres expérimentaux sur notre méthode de détection. / Nanostructures have demonstrated their utility in different optical applications. Our interest has focused on two of them: the spectral filtering and absorption spectroscopy. In the first case, the application is limited in particular by the rejection outside the passband of the filter nanostructures.In this thesis, I studied and developed a free-standing structure composed of two metalic subwavelength gratings encapsulated in a dielectric. This structure has an extinction at high wavelengths which improves the filter rejection. A fabricating process has been developed, and optical characterizations demonstrate experimentally the presence of the extinction of the transmission.In the second case, the nanoantennas conventionally used require optimization of the structure for each observed bond and limit the type of detectable molecules. I have proposed a new method of absorption spectroscopy of molecules based on nanorods. These structures composed of a free-standing dielectric rods array exhibit a perfect reflection disturbed by the presence of molecules around these rods. I have theoretically shown the potential of this method based on the spectral scanning reflection resonant with the incident angle and I compared to metalic nanoantennas described in the literature.Then, I fabricated and characterized nanogrilles of two different sections and showed the impact of experimental parameters on our detection method.

Spintronics is a dynamically developing branch of electronics which for transfer, processing and storing of information use not only electron charge but also its spin. Materials appropriate for a construction of spintronic devices should sustain the spin order for a sufficiently long time enabling a manipulation of spins. Simultaneously, in these materials the spin of electrons should be possible to transport fast and long enough across the device. In this work, heterostructure of GaAs/AlGaAs fulfilling these requirements is investigated by a pump-probe technique. In particular, long spin lifetimes of electrons in the heterostructure are studied using the resonant spin amplification method and with a use of the pulse picker. The nuclear spin polarization and the effect of an applied electric current on the studied heterostructure are also investigated in this work. Spectral filters are used to improve the existing experimental setup for the pump-probe technique and to measure a magnetooptical spectrum of the investigated heterostructure.

A wide range of applications currently utilize conventional optical elements to individually transform the phase, polarization, and spectral transmission/reflection of the incident radiation to realize the desired system level function. The material properties and the feasibility of fabrication primarily impact the device and system functionality that can be realized. With the advancement in micro/nano patterning, growth, deposition and etching technology, devices with novel and multiplexed optical functionalities have become feasible. As a result, it has become possible to engineer the device response in the near and far field by controlling the phase, polarization or spectral response at the micro scale. One of the methods that have been explored to realize unique optical functionalities is by varying the structural properties of the device as a function of spatial location at the sub-micron scale across the device aperture. Spatially varying the structural parameters of these devices is analogous to local modifications of the material properties. In this dissertation, the optical response of interference transmission filters, guided mode resonance reflection filters, and diffraction gratings operated in Littrow condition with strategically introduced spatial variation have been investigated. Spatial variations in optical interference filters were used to demonstrate wavelength tunable spatial filters. The effect was realized by integrating diffractive and continuous phase functions on the defect layer of a one-dimensional photonic crystal structure. Guided mode resonance filters are free space optical filters that provide narrow spectral reflection by combining grating and waveguide dispersion effects. Frequency dependent spatial reflection profiles were achieved by spatially varying the grating fill fraction in designed contours. Diffraction gratings with space variant fill fractions operating in Littrow condition were used to provide graded feedback profiles to improve the beam quality and spatial brightness of broad area diode lasers. The fabrication of space variant structures is challenging and has been accomplished primarily by techniques such as ruling, electron beam writing or complex deposition methods. In order to vary the desired structural parameter in a designed manner, a novel technique for the fabrication of space variant structures using projection lithography with a fidelity that rivals any of the current technologies was also developed as a part of this work. The devices exhibit wavelength dependent beam shaping properties in addition to spatial and spectral filtering and have potential applications in advanced imaging systems, graded reflectivity laser mirrors, and engineered illumination. The design, modeling, microfabrication and experimental characterization of space variant micro optical elements with novel optical functionalities are presented.