Wavefront Sensor Encoding for High-Resolution Phase Detection
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Solution Overview
Problem
Conventional optical imaging techniques fail to capture high-resolution data on the phase and coherence distributions of electromagnetic fields, leading to loss of valuable information and limitations in applications such as aberration compensation, depth of focus, and three-dimensional imaging.
Innovation Solution
An optical detection system comprising an encoder with a periodic pattern and an array of sensor cells, which applies modulation to collected light and processes intensity maps to determine mutual coherence, phase, and intensity distributions using a control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If conventional optical imaging techniques are used to measure intensity distribution, then the measurement process is simple and straightforward, but phase and coherence information is lost
Solution Approach 1:
The detection plane is divided into multiple sub-arrays, each corresponding to a unit cell of the encoder. This segmentation allows different regions to capture different aspects of the optical field (intensity, phase, coherence) simultaneously, enabling recovery of lost information without requiring a completely complex new system architecture
Solution Approach 2:
An encoder with periodic pattern is introduced as an intermediary element between the optical field and the sensor array. This encoder modulates the optical field to encode phase and coherence information into intensity variations that can be captured by conventional sensors, thereby recovering lost information while maintaining system simplicity
2Measurement precision
If reference beam or self-interference techniques are used for phase or coherence measurements, then additional information can be extracted, but the system becomes sensitive to environmental decoherence effects
Solution Approach 1:
The system uses self-interference of the modulated optical field itself to generate the measurement signal, rather than requiring an external reference beam. The encoder causes different parts of the optical field to interfere with each other, creating intensity patterns that directly encode phase and coherence information. This self-referential approach eliminates sensitivity to external environmental decoherence while maintaining measurement precision
3Measurement precision
If light field and plenoptic imaging techniques are used for spatial resolution, then three-dimensional information can be captured, but the resolution is limited to sub-diffraction limited
Solution Approach 1:
The system changes the key parameter of diffraction limit by using near-field propagation conditions instead of far-field approximations. By placing the sensor array in the near field of the encoder and utilizing evanescent wave coupling, the system achieves super-resolution beyond the diffraction limit. This parameter change enables high spatial resolution while maintaining versatility across different wavelength ranges through appropriate scaling of the encoder period and propagation distance
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 high-resolution detection of phase and coherence distributions, facilitating applications like aberration correction, three-dimensional imaging, and synthetic aperture imaging, and supporting various wavelength ranges including non-optical electromagnetic radiation.
Implementation Method 1
said encoder being configured for applying predetermined modulation to input light collected by the optical detection system, so as to direct the so-modulated light toward said sensor array
Implementation Method 2
a wavefront sensor including a lens array having a plurality of two-dimensionally arranged lenses and an optical detection element for detecting a light intensity distribution including converging spots formed by the lens array
Data Source
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AI summary
An optical detection system for detecting the wavefront of an incoming light beam is described. The system comprising an encoder (120) having a plurality of similar unit cells (122), and an array (140) of sensor cells (142) located at a distance downstream of said unit cells with respect to a general direction of propagation of input light through the system. The array of sensor cells defines a plurality of sub-array unit cells, each sub-array corresponding to a unit cell of said plurality of the unit cells of the encoder, and each sub-array comprising a predetermined number M of sensor elements. The encoder is configured to apply predetermined modulation to input light collected by the optical detection system, such that each unit cell of said encoder directs a portion of the collected input light incident thereon onto sub-array unit cell corresponding therewith and one or more neighboring sub-array unit cells within a predetermined proximity region (PR). The predetermined number M is determined in accordance with a predetermined number of sub-arrays unit cells within the predetermined proximity region.