Multiplexing volume holographic gratings for a spectral-spatial imaging system

論文發表人：駱遠 (亞利桑那大學光學學院博士班)

 

http://spie.org/

 

在影像系統中，多工光柵(Multiplexed Gratings)能將立體測試物不同深度的二維截面影像，個別地投射到照相機不同的對應面。多工光柵本身扮演著全像Bragg濾波器的角色，配合傳統光學影像元件，將可結合成"體積全像影像系統(Volume Holographic Imaging System) "。基於多工光柵，在系統中具有角度以及波長的高效能感應度特性，體積全像影像系統可將立體測試物的波長特性及空間資訊，在完全不需要對物體進行三維掃描情況下，便可同時萃取顯示出來。為達到上述特性，在設計多工光柵濾波器時，運用了所謂"角度式多工全像技術"，製作過程中則採用2毫米的PQ-PMMA全像紀錄元件。此外，理論模擬方面，結合精準偶合波(Rigorous Coupled Wave)方法來預測光柵濾波器表現度並得到最佳的實驗結果。

 

Multiplexed gratings can be used in an imaging system to project depth sections of a tested object onto different surface locations of a camera.  This technique is based on volume holographic Bragg filters used in conjunction with conventional optical imaging components to form a volume holographic imaging system (VHIS).  Due to the high angular selectivity and high wavelength selectivity of the system, the VHIS can be used to provide spectral-spatial information of the object that is being observed, and eliminate the need for mechanical scanning.  Multiple sections of the object can be viewed by using angle multiplexed holographic elements formed in a volume holographic material.  To achieve the highly selective characteristic of a holographic filter, 2mm thick samples of phenanthrenequinone-doped methyl methacrylate (PQ-PMMA) is used as the holographic recording materials.  Rigorous coupled wave models are used to theoretically predict the performance of the gratings.  Results from both modeling and experiments are presented.