Holographic Fabry-Perot spectrometer.
We propose a spectrum analyzer based on the properties of a hologram recorded with the field transmitted by a Fabry-Perot etalon. The spectral response of this holographic Fabry-Perot spectrometer (HFPS) is analytically investigated in the paraxial approximation and compared with a conventional Fabry-Perot etalon of similar characteristics. We demonstrate that the resolving power is twice increased and the free spectral range (FSR) is reduced to one-half. The proposed spectrometer could improve the operational performance of the etalon because it can exhibit high efficiency and it would be insensible to environmental conditions such as temperature and vibrations. Our analysis also extends to another variant of the HFPS based on holographic multiplexing of the transmitted field of a Fabry-Perot etalon. This device increases the FSR, keeping the same HFPS performance.
Generation of femtosecond paraxial beams with arbitrary spatial distribution.
We present an approach to generate paraxial laser beams with arbitrary spatial distribution in the femtosecond time regime. The proposed technique is based upon a pair of volume phase holographic gratings working in parallel arrangement. It exploits the spatial coherence properties of the incoming laser beam in a compact and robust setup that mitigates angular and spatial chirp. The gratings were recorded in a photopolymerizable glass with a high optical damage threshold and a large optical throughput. Setup performance is studied and experimentally demonstrated by generating Laguerre-Gaussian femtosecond pulses.
Sol-gel approach for the preparation of holographic and photorefractive materials
This work describes how the sol-gel process can be a useful approach for the preparation of hybrid materials showing either holographic as well as photorefractive properties. The composition of the holographic and photorefractive materials prepared through the sol-gel approach are completely based on their respective multi-functional polymer analogues, but in the polymer acting as host matrix which is replaced by a nanoporous silica matrix. Such a replacement infers an overall improvement in both the optical and the mechanical properties of the material. The goodness of the properties found for either the holographic as well as the photorefractive materials demonstrate the validity of these new synthetic routes for the preparation of optical recording materials.