Annular Spherical Mirror Array for Large-Area Hologram Capture
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Solution Overview
Problem
Existing hologram acquisition systems using self-interference digital holography with incoherent light sources face a trade-off between hologram resolution and recording area, as increased curvature of phase modulation mirrors improves resolution but reduces the hologram recording area due to optical path differences exceeding the coherence distance.
Innovation Solution
A hologram acquisition apparatus with a beam splitter and a second reflective optical element formed as an annular spherical array with concentric, discontinuous surfaces, where segment regions have varying curvatures or sagittal heights to maintain optical continuity and coherence within the coherence distance, allowing high-resolution holograms to be recorded over a large area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the curvature of phase modulation mirrors is increased to improve hologram resolution, then the optical path difference between mirror center and edge increases, causing the optical path difference to exceed the coherence distance of incoherent light sources, which reduces the hologram recording area
Solution Approach 1:
The second reflective optical element is divided into multiple segment regions with different curvatures. Each segment region has a curvature optimized for its specific position, allowing the system to maintain high resolution across the entire recording area while keeping optical path differences within the coherence distance of incoherent light sources.
Solution Approach 2:
Different regions of the reflective optical element are assigned different optical properties (curvatures). The segment regions have varying curvatures matched to their local requirements, enabling each region to contribute to high-resolution hologram recording while maintaining overall system coherence.
2Measurement precision
If a spherical mirror with large curvature is used as a phase modulation mirror to obtain high-resolution hologram information, then the optical path between light incident at the center and periphery of the mirror is increased, causing object information not to be recorded as a hologram when the optical path difference exceeds the coherence distance
Solution Approach 1:
The reflective optical element is segmented into multiple regions, each with optimized curvature. This segmentation ensures that no single region creates excessive optical path differences, maintaining recording completeness across the entire aperture while achieving high resolution through the collective contribution of all segments.
Solution Approach 2:
The curvature parameter of the reflective optical element is varied across different segment regions. By changing the curvature parameter locally rather than using a uniform large curvature, the system achieves high resolution while keeping optical path differences within acceptable limits for incoherent light sources.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables high-resolution holograms to be obtained in a large recording area by ensuring sufficient curvature and optical path differences are within the coherence distance, preventing aberrations and enhancing the recording capability of the system.
Implementation Method 1
a beam splitter configured to split light emitted from an object into a first beam and a second beam
Implementation Method 2
through phase modulation mirrors having different curvatures of each of the channels, modulate light separated to have different characteristics
Implementation Method 3
the SIDH can use the beam splitter to merge the two modulated light beams into one channel and thereby form an interference fringe
Data Source
AI summary
A hologram acquisition apparatus and a hologram acquisition system are disclosed. A hologram acquisition apparatus includes a beam splitter configured to split light emitted from an object into a first beam and a second beam, a first reflective optical element configured to receive and emit the first beam to the beam splitter, and a second reflective optical element configured to receive and emit the second beam to the beam splitter and formed as an annular spherical array having discontinuous surfaces, wherein the second reflective optical element has a plurality of segment regions that are concentric and divided to have the discontinuous surfaces and, the plurality of segment regions are formed to have the same focal point.