Polarization Imaging for Measuring Internal Optical Anisotropy
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Solution Overview
Problem
Existing optical measurement technologies struggle to accurately measure variations in polarization states caused by birefringence, circular dichroism, and scattering within subjects due to reliance on non-polarized environmental light, leading to difficulties in measuring internal characteristics and sensitivity to speckle noise and scattering factors.
Innovation Solution
An optical measurement apparatus that uses controlled polarized irradiation light with a degree of polarization of 50 to 100% and ellipticity of 50 to 100%, combined with a polarization imaging unit capable of spatially separating and calculating Stokes parameters from snapshots, to measure variations in polarization states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If non-polarized environmental light is used for measurement, then the measurement system is simple and does not require controlled light sources, but the polarization state variations caused by internal subject characteristics such as birefringence and circular dichroism cannot be measured
Solution Approach 1:
The patent applies preliminary action by controlling the polarization state of the irradiation light before it reaches the subject. The light source is pre-configured to emit light with specific polarization characteristics (linear, circular, or elliptical polarization), which then interacts with the subject's internal structures. This preliminary polarization control enables the detection of internal characteristics like birefringence and circular dichroism that would otherwise be invisible, resolving the contradiction between system simplicity and measurement precision.
2Ease of operation
If the polarization state of irradiation light is not controlled, then the light source can use natural environmental light, but speckle noise occurs due to phase fluctuation and measurement under scattering environments becomes difficult
Solution Approach 1:
The patent applies parameter changes by systematically varying the polarization state parameters of the irradiation light. The system can switch between different polarization states (linear, circular, elliptical) and adjust polarization angles, enabling the measurement to adapt to different subject characteristics and environmental conditions. This parameter control eliminates speckle noise by preventing coherent interference and overcomes scattering effects by optimizing polarization alignment, thereby improving measurement reliability while maintaining operational flexibility.
3Measurement precision
If a rotating polarizer method is used to measure polarization state, then Stokes parameters can be calculated, but measurement on dynamic subjects or subjects with temporally varying polarization states is difficult
Solution Approach 1:
The patent replaces the mechanical rotating polarizer system with a stationary polarization imaging unit that uses polarization-sensitive detectors or fixed polarization optics combined with image processing. This substitution eliminates the mechanical rotation component, allowing simultaneous capture of polarization information across the entire field of view in a single snapshot. The system maintains Stokes parameters calculation capability through computational methods while achieving high-speed measurement suitable for dynamic subjects, thus resolving the contradiction between measurement precision and productivity.
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 accurate measurement of internal polarization characteristics and anisotropy of subjects by controlling the polarization state of irradiation light and imaging the resulting measurement light, providing detailed subject information and improved sensitivity to anisotropy.
Implementation Method 1
a polarization diffraction grating that spatially separates the incident measurement light into a left-handed circularly polarized component and a right-handed circularly polarized component
Implementation Method 2
measurement of a polarization state of light that is subjected to scattering, reflection, absorption, and the like by a subject
Implementation Method 3
measurement of a polarization state of light that is subjected to scattering, reflection, absorption, and the like by a subject
Implementation Method 4
measurement of a polarization state of light that is subjected to scattering, reflection, absorption, and the like by a subject
Implementation Method 5
measure a variation of the polarization state which is caused by birefringence, circular dichroism, linear dichroism, scattering, multiple-interference, and the like at the inside of the subject
Data Source
AI summary
Provided is an optical measurement apparatus including: a polarized light irradiation unit 10 that irradiates a subject Ob with irradiation light of which polarization is controlled; and a polarization imaging unit 20 that images a polarization state of measurement light occurring due to scattering or the like of the irradiation light by the subject Ob, calculates Stokes parameters of the measurement light, and measures a variation of a polarized component occurring between the irradiation light and the measurement light. Since the subject is irradiated with irradiation light of which a polarization state is controlled, it is possible to acquire subject information that is difficult to measure in a case of irradiating the subject with natural light, and it is also possible to suppress noise or the like that occurs when measuring polarization by irradiating the subject with irradiation light of which a polarization state is unstable.