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Design, Fabrication And Applications Of Microstructured Optical Elements And Devices

Posted on:2014-10-24Degree:DoctorType:Dissertation
Country:ChinaCandidate:D P KongFull Text:PDF
GTID:1268330422459325Subject:Optics
Abstract/Summary:PDF Full Text Request
With unique structural features, novel optical properties and excellentprocessing performance, the polymer microstructured fiber has become an importantpart in the research field of fiber optics, as well as a research hotspot at home andabroad.3D stereoscopic imaging technology is also a research focus with importantresearch significance and application value. In this thesis, we focus on thefabrication of polymer microstructured optical fiber and its applications in imagetransmission and3D fiber-optic endoscope, fabrication and application of thepolymer fiber bundle and fabrication of gradient-index lens array and its applicationin3D multi-aperture imaging device.The first chapter of this thesis is a brief introduction of the following contents:the development of optical fiber and the light transmission theory in optical fibers;the concept, classification and current research works of microstructured fiber; thecharacteristics, commonly used production methods and the research status quo ofthe polymer fiber-optic image bundles and microstructured image fibers; the historyof the endoscope and the characteristics of stereo endoscope; the status quo of themulti-aperture3D imaging technology. On this basis of this introduction, theresearch purpose, significances and the characteristics of this thesis are proposed.In the second chapter, several fabrication methods of the microstructure fiberpreforms are introduced. Based on the analysis of the advantages and disadvantagesof these methods,a new method, injection molding method, is proposed. Moldingprocess of the polymer microstructured optical fiber preform is researched, and thematerials used in experiment are PMMA and Topas COC. Polymer microstructuredfiber drawing process and the transmission loss of Topas COC microstructuredterahertz fiber are also studied experimentally. As the experimental result shows, thetransmission loss of suspended core sub-wavelength THz fiber at206GHz is0.034dB/cm, and for anti-resonant reflection type THz fiber, the transmission loss at206GHz and1.2THz are0.122dB/cm and0.120dB/cm, respectively.In the third chapter, the properties and types of materials commonly used in thefabrication of polymer microstructure imaging fiber are introduced firstly. Based on this introduction, the polymer material for microstructured polymer imaging fiber ischosen. Then the fabrication process of the microstructured imaging fiber is studied,and the imaging properties of this fiber are analyzed theoretically and characterizedexperimentally. The results show that the polymer microstructured imaging fiber hasgood imaging capability, wherein for microstructured imaging fiber with an outerdiameter of250μm, monofilament diameter is3μm, the theoretical limit resolution isup to192lp/mm, and the scale image of10μm can be transmitted.In the fourth chapter, we make a long polymer imaging fiber bundle with thelength of15m by arranging and lamination method. The fabrication process andtransmission characteristics of this polymer imaging fiber bundle are also studied.With matched eyepiece (or coupling lens) and image sensors, this long polymerimaging fiber-bundle can be used for exploration application after earthquake. Then,the study of the fabricating and stretching processes of compact polymer imagingfiber performs is shown as well, and both circular and regular hexagon polymerimaging fiber preforms are developed. The pixel number of this imaging fiber is upto approximately7100. At the same time, with matched eyepiece and image sensors,the application of this imaging fiber in safety monitoring is explored initially. Theresults show that the imaging fiber has a good image transmission capability whichcan be applied in some special occasions.The fifth chapter introduces the basic principle of binocular stereo vision firstly.Based on this principle, the structure of the3D fiber-optic endoscope system isdesigned, and the selection principles and methods of objective lenses and eyepiecesin this system are shown, as well as the design principles of angle between twoobjectives. On this basis, with home-made polymer imaging fibers and matchedeyepieces and objective lenses, a3D fiber-optic endoscope binocular stereo visionsystem is built, which has been proven to have good stereoscopic image capturingcapabilities. Finally, a compact eyewear-style3-D endoscope derived from polymerimaging fiber is designed and fabricated.The sixth chapter introduces the basic principles, research status and severaltypical structures of multi-aperture3D image optical obtainment devices firstly. Onthis basis, the gradient-index lens array is used in the3D multi-aperture imagingsystem. Then, the12×8gradient-index lens array is fabricated, and assembled witha modified Nikon J1digital camera which has a matched camera lens with35mm focal length and super-large aperture. After analyzing and calculating the depthresolution, the depth of field and field angles of this imaging system theoretically,moreover, testing the depth resolution and field angle experimentally, the resultshows that theoretical and experimental results are basically identical. The depthresolution and field angle of the camera are4%and29.4°respectively.Chapter7is the summary of the research works undertaken during my PhDprogram and the development direction of my academic career.
Keywords/Search Tags:microstructured polymer fiber, image transmission fiber, fiberstereo-endoscope, multi-aperture stereo imaging, gradient-index lens array
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