Self-Interference Holography With Calibration-Free Phase Shifting
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Solution Overview
Problem
Conventional holographic imaging methods require complex illumination and wavelength calibration for phase shifting, limiting their efficiency and applicability in environments where coherent light is not available.
Innovation Solution
A method and apparatus that transforms light into multiple co-linear co-propagating beams with unique spherical phase curvatures, allowing interference without wavelength calibration, and records these patterns in a single exposure for super-resolved image reconstruction using a birefringent lens and broadband quarter-wave plate with micro-polarizer arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional holographic imaging methods are used, then wavelength calibration is required for phase shifting, but this increases device complexity and reduces ease of operation
Solution Approach 1:
The system uses self-interference of the light field where the object light interferes with itself after passing through the birefringent lens, eliminating the need for external reference beams and wavelength calibration procedures. The phase information is encoded through the geometric optics of the birefringent lens rather than through calibrated phase shifters.
Solution Approach 2:
The patent replaces mechanical or electronically controlled phase shifters (which require wavelength calibration) with a birefringent lens that introduces phase differences through its optical path. The phase modulation is achieved through the material properties and geometry of the birefringent lens rather than through adjustable mechanical components.
2Measurement precision
If multiple phase factors are recorded sequentially, then measurement precision is improved, but this increases loss of time
Solution Approach 1:
The patent encodes multiple phase factors in the spatial dimension by recording them in different regions of the image sensor simultaneously. The birefringent lens creates laterally separated interference patterns corresponding to different phase factors, allowing parallel acquisition rather than sequential recording.
Solution Approach 2:
Multiple interference patterns with different phase factors are merged into a single image capture. The system records all necessary phase information simultaneously in one exposure, combining what would otherwise require multiple sequential measurements into a single event.
3Adaptability or versatility
If conventional illumination methods are used, then imaging is possible, but this increases device complexity and requires coherent light
Solution Approach 1:
The birefringent lens-based self-interference system works with incoherent light sources, making the system universally applicable to various illumination conditions. The method does not require the stringent coherence conditions needed for conventional holography, allowing use with standard incoherent light sources like LEDs or lamps.
Solution Approach 2:
The system uses the light field from the object itself to create the interference pattern, without requiring a separate reference beam. This self-interference approach eliminates the need for complex coherent illumination systems and reference beam paths, simplifying the overall imaging setup.
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
Enables super-resolution imaging without wavelength calibration, improving signal-to-noise ratio and reducing exposure time, suitable for low-light imaging and dynamic scenes.
Implementation Method 1
transform light into multiple co-linear co-propagating beams with unique spherical phase curvatures... using a birefringent lens
Implementation Method 2
broadband quarter-wave plate with micro-polarizer arrays
Implementation Method 3
cause a recording of the interference of the two beams at an image recording plane
Data Source
AI summary
An apparatus and method are introduced to produce a hologram of an object from electromagnetic radiation, such as incoherent light, received from the object. The electromagnetic radiation is received by a receiving assembly and transformed into a plurality of co-linear co-propagating beams with different focal distances. The interference of the plurality of beams is enabled by projecting components of each beam along a common polarization direction. The interference patterns thus formed are recorded and then processed to form the hologram of the object.