Tunable Filter Parallel Light Flux Polarization Segmentation
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Solution Overview
Problem
Conventional light source apparatuses using unidirectional linearly polarized light result in low energy efficiency, and those with polarizers adjacent to liquid crystal elements face issues with polarization state confusion, leading to inaccurate modulation of output light.
Innovation Solution
A tunable filter and light source apparatus that utilize parallel light fluxes through a polarization splitter and wavelength dispersion spectroscopic element, allowing for accurate modulation and measurement of spectral distribution by independent modulation of P and S polarized light components, preventing polarization state locality and enhancing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If unidirectional linearly polarized light is used in conventional light source apparatuses, then the modulation function is achieved, but energy efficiency deteriorates
Solution Approach 1:
The invention segments the polarization state into independent P and S components, allowing each to be modulated independently through separate optical paths. This segmentation enables full utilization of both polarization directions, transforming the energy efficiency problem into a controllable parameter rather than a fixed limitation.
Solution Approach 2:
The invention introduces dynamic control mechanisms including voltage-controlled liquid crystal elements and electro-optic modulators that can switch between different polarization states in real-time. This dynamic capability allows the system to adaptively route and modulate both P and S polarized light, maximizing energy utilization while maintaining modulation functionality.
2Ease of operation
If a polarizer is provided adjacent to a liquid crystal element, then the modulation function is implemented, but polarization state confusion occurs leading to inaccurate modulation
Solution Approach 1:
The invention introduces an intermediary optical path using beam splitters and wave plates positioned between the polarizer and liquid crystal element. This intermediary structure acts as a buffer that decouples the polarization state from the modulation process, preventing direct confusion while enabling accurate independent control of P and S components.
Solution Approach 2:
The invention replaces the mechanical polarizer-liquid crystal arrangement with an electro-optic modulation system where voltage-controlled liquid crystal elements directly modulate the polarization state without requiring adjacent polarizers. This substitution eliminates the source of polarization confusion while maintaining modulation capability through electrical control.
3Measurement precision
If NA is kept small to prevent polarization confusion, then polarization state accuracy is improved, but light flux transmission deteriorates
Solution Approach 1:
The invention transitions from a single-dimensional NA constraint to a multi-dimensional control approach by independently managing P and S polarization components through separate optical paths. This dimensional separation allows the system to achieve high polarization accuracy without being constrained by a single NA value, as each polarization component can be optimized independently.
Solution Approach 2:
The invention dynamically adjusts optical parameters including NA, beam diameter, and polarization angle throughout the optical path. By changing these parameters adaptively rather than fixing them, the system can maintain high polarization state accuracy while optimizing light flux transmission at different stages of the modulation process.
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 accurate reflection of modulation in both reflective and transmissive spatial modulator devices, improving energy efficiency and reducing polarization state confusion, resulting in output light that accurately represents the intended spectral distribution.
Implementation Method 1
a first polarization splitter (120) that splits the parallel light into P polarized light and S polarized light
Implementation Method 2
a wavelength dispersion spectroscopic element (146) that generates spectral images of the P polarized light and the S polarized light
Implementation Method 3
a reflective spatial modulator device (150) including a first liquid crystal element array (152) and a second liquid crystal element array (154)
Data Source
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AI summary
Provided is a tunable filter including: a polarization splitter that splits input light into two linearly polarized light rays of mutually orthogonal vibration directions; a wavelength dispersion spectroscopic element that splits the two linearly polarized light rays split by the polarization splitter, into two spectral images having spatial spread in one direction, the two spectral images corresponding to the two linearly polarized light rays; and a reflective spatial modulator device that modulates and reflects linearly polarized light in each wavelength region for the two spectral images independently from each other, where modulated light reflected at the reflective spatial modulator device reenters the wavelength dispersion spectroscopic element and the polarization splitter, thereby splitting and outputting the modulated light, as output light in a wavelength region modulated by the reflective spatial modulator device and output light in a wavelength region not modulated, and input light and reentered light to the polarization splitter and input light and reentered light to the wavelength dispersion spectroscopic element are parallel light fluxes.