Novel Angular Domain Spectroscopic Analysis Devices and Techniques.

摘要

The first objective of this thesis is to design, fabricate and characterize Radial Angular Filter Arrays (RAFAs). The motivation is to replace bulky and slower goniometer-based instruments or complicated interferometric systems to achieve low-cost, real-time and simplified optical scattering measurement. In addition, RAFAs are designed to support angle-resolved spectroscopic analysis for structural characterization, bio-sensing, and material identification. RAFAs originate from Angular Filter Array (AFA) in Angular Domain Imaging (ADI). They consist of radially-distributed micro-machined channels in a silicon substrate. Each channel collects photons emitted from the focal point at a specific angle and only passes through photons traveling within a small acceptance angle of the channel direction. This angular filtering function is independent of photon wavelength in the visible and near infrared range. A RAFA provides a means to obtain both angular and spectral information of scattered light in a single exposure. The primary contribution of this thesis project in this field is to develop a RAFA from a concept to a fully functioning device, which expands the applications of AFA beyond biomedical imaging and facilitates the applications of angular spectroscopy. A novel optical characterization system based on both Nano Hole Arrays and RAFAs for potential Surface Plasmon Resonance sensing applications is proposed and tested.;The second objective of this thesis is to advance the angular domain spectroscopic analysis in the biomedical imaging field by applying the multi-spectral analysis to reflectance ADI setups other than the conventional transillumination systems. This new technique allows non-invasive in vivo angular domain spectroscopic imaging samples too thick to perform transillumination. The contribution in this field is to add spectroscopy to the existing Deep-Illumination ADI system. A series of improvements in setup and image processing are practiced to enable Deep-Illumination Angular Domain Spectroscopic Imaging (DI-ADSI) for tissue-mimicking phantoms. The results obtained demonstrate that its depth penetration, field of view and spatial resolution are between micro-reflectance-imaging technologies such as Optical Coherent Tomography and Confocal Microscopy, and macro-reflectance-imaging technologies such as Diffuse Optical Tomography, satisfying the value-proposition of DI-ADSI. It suggests that DI-ADSI has the potential for low-cost and fast in vivo tissue scanning for superficial targets.;Keywords: Radial Angular Filter Array; Angular Spectroscopy; Optical Scattering; Angular Domain Imaging; Angular Domain Spectroscopic Imaging.