Chalcogenide Athermal Glasses for Temperature-Stable Infrared Optics
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Solution Overview
Problem
Conventional optical components and systems, such as etalons, fiber-based strain sensors, laser gain media, and optical lens systems, face challenges in maintaining performance stability due to temperature changes, with existing materials failing to meet the requirement of zero thermal expansion and refractive index variation, leading to errors in strain sensing and optical path-length changes.
Innovation Solution
Development of athermal glasses and systems using chalcogenide glass compositions, specifically represented by formulas like As40Se60 and As22Se78, which exhibit a figure-of-merit (FOM) varying by 5 ppm/°C or less, ensuring minimal dependence on temperature changes, applied in solid etalons, fiber-based strain sensors, and optical lens systems to maintain optical performance across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical materials are used, then manufacturing and design are straightforward, but temperature-induced errors cause performance degradation
Solution Approach 1:
The patent employs composite glass compositions combining multiple elements (As, Se, S, Ge, Te, Bi, Sb, In, Ga) to create materials with tailored thermal and optical properties. These composite materials achieve near-zero figure-of-merit values by balancing thermal expansion and refractive index temperature coefficients through careful compositional design, thereby resolving the contradiction between reliability and complexity.
Solution Approach 2:
The invention systematically varies compositional parameters (mole percentages of different elements) to optimize the figure-of-merit. By changing the ratios of chalcogenide elements and adding specific modifiers, the patent achieves precise control over thermal expansion and refractive index temperature dependence, transforming the material properties to meet athermal requirements.
2Measurement precision
If athermal glass compositions are used, then temperature-induced errors are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by optimizing specific compositional regions within the glass formulation space. Rather than requiring extreme precision across all parameters, the invention identifies specific element ratios (e.g., As:Se:S proportions) that naturally provide athermal behavior, allowing manufacturing with moderate tolerances while maintaining high measurement precision.
Solution Approach 2:
The patent converts the typically harmful effect of thermal expansion into a beneficial feature by selecting compositions where thermal expansion and refractive index changes compensate each other. The temperature-dependent properties that normally cause errors are harnessed to cancel out, turning manufacturing variations into self-correcting mechanisms that maintain measurement accuracy.
3Device complexity
If single-material athermal components are used, then system design is simplified, but material property requirements become more stringent
Solution Approach 1:
The patent achieves athermal behavior by carefully adjusting material parameters (compositional ratios, doping levels) to balance thermal expansion and refractive index temperature coefficients. This allows single-material components to provide athermal performance, simplifying optical system design while meeting stringent stability requirements through precise parameter optimization.
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 athermal glasses and systems effectively reduce temperature-induced errors in optical components, enabling temperature-independent performance in infrared applications, such as strain sensing and wavelength stabilization, while simplifying the design and fabrication of multi-element lens systems by minimizing curvature requirements.
Implementation Method 1
α is the linear thermal expansion
Implementation Method 2
dn/dT is the temperature derivative of the refractive index
Data Source
AI summary
Athermal glasses and athermal systems for infrared optical components and systems are disclosed.