Mots-clés de l'auteur: Endoscopy ; Digital Phase Conjugation ; Fiber imaging ; Multimode fibers ; Multicore fibers ; Capillary waveguides ; Photoacoustic imaging ; Two-photon imaging ; Fluorescence imaging ; Saturated excitation microscopy.

Learn about the theory, techniques and applications of wavefront shaping in biomedical imaging using this unique text. With authoritative contributions from researchers who are defining the field, cutting-edge theory is combined with real-world practical examples, experimental data and the latest research trends to provide the first book-level treatment of the subject. It is suitable for both background reading and use in a course, with coverage of essential topics such as adaptive optical microscopy, deep tissue microscopy, time reversal and optical phase conjugation, and tomography. The latest images from the forefront of biomedical imaging are included, and full-colour versions are available in the eBook version. Researchers, practitioners and graduate students in optics, biophotonics, biomedical engineering, and biology who use biomedical imaging tools and are looking to advance their knowledge of the subject will find this an indispensable resource.

Multi-mode fibers (MMFs) can convey multiple physical variables which enables them to be used in different applications. In this dissertation, we study two specific applications of MMFs: imaging and communications. The use of MMFs for imaging or analog image transmission has long been of fundamental interest and is now being pursued vigorously for applications such as endoscopic in vivo imaging, brain studies or sugeries and cancer detection. An endoscope using one MMF would be potentially much more compact than current endoscopes, which may employ either a bundle of fibers or one fiber with a scanning probe head. The use of MMFs for space-division multiplexing (SDM) in optical communications has also gained a lot of interest recently. SDM uses different modes in MMFs as independent data channels in order to increase the link capacity and overcome the information-theoretic capacity limit of long-haul single-mode fiber systems. The properties of transmission fibers and fiber amplifiers are crucial to the ultimate feasibility of spatially multiplexed long-haul systems. In transmission fibers, low group delay spread minimizes receiver signal processing complexity, while large modal effective areas minimize nonlinear effects. In fiber amplifiers, low mode-dependent gain (MDG) minimizes the loss of capacity and the potential for outage. In the first part of this dissertation, we study imaging through a single MMF. In order to do imaging through a MMF we need to first sample an object using a set of intensity patterns at the fiber output. The image of the object can then be reconstructed using the measured optical powers that reflect from the object and couple back into the MMF. We demonstrate two methods for imaging through a MMF. In the first method a sequence of localized intensity patterns (spots) are used to sample an object at different locations and an image may be obtained using simple local reconstruction. In the second method a sequence of random intensity patterns are used to sample an object and an image may be obtained by solving a linear optimization problem. We first develop a method for synthesis of a desired intensity profile at the output of a MMF with random mode coupling by controlling the input field distribution using a spatial light modulator Abstract v (SLM). We pose the problem as optimization of an objective function, and derive a theoretical lower bound on the achievable objective function. We present an adaptive sequential coordinate ascent (SCA) algorithm for controlling the SLM, which does not require characterizing the full transfer characteristic of the MMF, and which converges to near the lower bound after one pass over the SLM blocks. We then study imaging using random patterns and optimization-based reconstruction and experimentally demonstrate endoscopic imaging through a MMF using this method. we show that when using local reconstruction, the number of independently resolvable image features is bounded by Ns, the number of spatial modes per polarization propagating in the MMF, but nonlocal reconstruction based on linear optimization can increase the number of resolvable features to 4Ns. The factor-of-four resolution enhancement is due to mixing of modes by the squaring inherent in field-to-intensity conversion. All previous methods for imaging through MMF can only resolve Ns features in the image. Most of these methods use localized intensity patterns for sampling the object and use local image reconstruction. In the second part of this dissertation, we demonstrate two adaptive methods to equalize MDG in multi-mode erbium-doped fiber amplifiers (MM-EDFAs). The first method is to place a SLM in line with the amplifier pump laser to control the modal content of the pump. The second method is to place an SLM immediately after the MMEDFA to directly control the modal gains in the signal. We compare the performance of the two methods applied to a MM-EDFA with a uniform erbium doping profile, supporting 12 signal modes in two polarizations. We show that root-mean-squared (RMS) MDGs lower than 0.5 dB and 1 dB can be achieved in systems having frequency diversity orders of 1 and 100, respectively, while causing less than a 2.6-dB loss of mode-averaged gain (MAG).

This book introduces double-prism multi-mode scanning theory and technology, focusing on double Risley-prism, multi-mode scanning models, methods and key techniques applied in multi-mode optical scanning and target tracking fields. It is first book to systematically and comprehensively describe basic multi-mode scanning theory and practical implementation techniques utilizing double Risley prisms. It includes rigorous modeling of double Risley-prism multi-mode scanning systems and high-efficiency solution algorithms for inverse problems with abundant illustrative examples and scanning error analyses, along with design guidance and performance test on specific scanning devices. Further, it presents the latest research results for forward scanning models and inverse tracking algorithms, sub-microradian fine scanning modeling with tilting double Risley prisms, nonlinear control strategy for double prism motion, calibration and experiment techniques for various double-prism layouts, as well as opto-mechanical system design and analysis. Featuring rigorous theoretical derivations illustrated with corresponding examples and original scanning apparatus, the book is a valuable reference resource for those developing and applying multi-mode scanning techniques in photoelectric scanning and tracking areas.

CD-ROM contains: a software package for designing fiber-optic communication systems called "OptiSystem Lite" and a set of problems for each chapter.

This proceedings volume presents the very latest developments in non-astronomical adaptive optics. This international workshop, the sixth in a biennial series, was the largest ever held and boasted significant involvement by industry. Adaptive optics is on the verge of being used in many products; indeed, at this meeting, the use of adaptive optics in DVD players was disclosed for the first time. Sample Chapter(s). Liquid Crystal Lenses For Correction Of Presbyopia (586 KB). Contents: Wavefront Correctors and Control: Liquid Crystal Lenses for Correction of Presbyopia (G Li & N Peyghambarian); Woofer-Tweeter Adaptive Optics (T Farrell & C Dainty); Wavefront Sensors: A Fundamental Limit for Wavefront Sensing (C Paterson); Direct Diffractive Image Simulation (A P Maryasov et al.); Adaptive Optics in Vision Science: A Study of Field Aberrations in the Human Eye (A V Goncharov et al.); Characterization of an AO-OCT System (J W Evans et al.); Adaptive Optics in Optical Storage and Microscopy: Commercialization of the Adaptive Scanning Optical Microscope (ASOM) (B Potsaid et al.); Towards Four Dimensional Particle Tracking for Biological Applications (H I Campbell et al.); Adaptive Optics in Lasers: New Results in High Power Lasers Beam Correction (A Kudryashov et al.); Adaptive Optics Control of Solid-State Lasers (W Lubeigt et al.); Adaptive Optics in Communication and Atmospheric Compensation: Fourier Image Sharpness Sensor for Laser Communications (K N Walker & R K Tyson); Adaptive Optics System for a Small Telescope (G Vdovin et al.); and other papers. Readership: Industry- and university-level researchers in optics and laser physics.

This book focuses on a research field that is rapidly emerging as one of the most promising ones for the global optics and photonics community: the “lab-on-fiber” technology. Inspired by the well-established "lab on-a-chip" concept, this new technology essentially envisages novel and highly functionalized devices completely integrated into a single optical fiber for both communication and sensing applications. Based on the R&D experience of some of the world's leading authorities in the fields of optics, photonics, nanotechnology, and material science, this book provides a broad and accurate description of the main developments and achievements in the lab-on-fiber technology roadmap, also highlighting the new perspectives and challenges to be faced. This book is essential for scientists interested in the cutting-edge fiber optic technology, but also for graduate students.