Experimental demonstration of extended depth-of-field f/1.2 visible High Definition camera with jointly optimized phase mask and real-time digital processing

Increasing the depth of field (DOF) of compact visible high resolution cameras while maintaining high imaging performance in the DOF range is crucial for such applications as night vision goggles or industrial inspection. In this paper, we present the end-to-end design and experimental validation of an extended depth-of-field visible High Definition camera with a very small f-number, combining a six-ring pyramidal phase mask in the aperture stop of the lens with a digital deconvolution. The phase mask and the deconvolution algorithm are jointly optimized during the design step so as to maximize the quality of the deconvolved image over the DOF range. The deconvolution processing is implemented in real-time on a Field-Programmable Gate Array and we show that it requires very low power consumption. By mean of MTF measurements and imaging experiments we experimentally characterize the performance of both cameras with and without phase mask and thereby demonstrate a significant increase in depth of field of a factor 2.5, as it was expected in the design step

The mitochondrial genome of the brown alga Laminaria digitata: a comparative analysis

We report here the complete sequence of the mitochondrial genome of the brown alga Laminaria digitata (Hudson) J.V. Lamouroux. L. digitata mtDNA is a circular molecule of 38,007 bp (64.9 % A+ T), encoding 63 genes and 3 ORFs and with only 6-7 % of non-coding sequences. Based on gene content and order, its overall organization is very similar to that of the mitochondrial genome of Pylaiella littoralis, another brown alga belonging to a different sublineage of the Phaeophyceae. In particular, the two genomes share unusual features, which hence could be unique to brown algae among the heterokont lineage, namely the presence of a rn5 gene, a short nad I I gene, a cox2 gene with a large in-frame insertion and alpha-proteobacterial-like promoter sequences. On the other hand, L. digitata lacks the sequences which are thought to have been transmitted horizontally to the P. littoralis genome, that is, the group-II introns in the rnl and cox1 genes, and it features only traces of an ancestral T7-like RNA polymerase. Distance phylogenetic trees inferred from concatenated mitochondrial genes confirm that speciation of brown algae occurred recently compared to other heterokonts

Holographic bulk grating in a photopolymer for pulse stretching in a CPA laser

We report large-aperture volume Holographic Chirped Bragg Reflector recorded in a photopolymer material. It permits to realize compact optical pulse stretchers (230-ps) for femtoseconds lasers

Focus optimization with binary wave-front coding

10.1109/QELS.2008.4552724Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series

Reconfigurable transmission lines based on self-complementary metasurfaces

This paper presents a new type of metasurface, which consists of a chessboard-type layout, made of electrically small complementary metallic patches and apertures. Depending on whether the vertexes of the patches are interconnected or not, the structure may support or not a propagating quasi-TEM mode. This offers the possibility of designing arbitrary transmission line paths on the metasurface by dynamically changing the status of the vertex connections. The concept is demonstrated with simulated results