Terahertz Ellipsometer Using Rotatable Wire Grid Polarizers
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Solution Overview
Problem
There is a lack of commercially available ellipsometer or polarimeter systems capable of operating in the Terahertz frequency range, making it difficult to practice high-quality Terahertz ellipsometry in various locations, and existing systems do not provide a convenient method for controlling the azimuthal angle of linearly polarized beams of electromagnetic radiation.
Innovation Solution
A Terahertz ellipsometer or polarimeter system comprising a backward wave oscillator, a rotatable polarizer, a stage for supporting a sample, a second rotatable polarizer, and a Golay cell detector, with first and second rotating elements that can be distributed on either side of the stage, utilizing a wire grid polarizer and a rotating retarder to control the polarization state of the electromagnetic radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional ellipsometer systems are used, then they can determine sample characteristics, but they cannot operate in the Terahertz frequency range
Solution Approach 1:
The patent changes the operating parameters of the ellipsometer system by selecting specific Terahertz frequency range components (backward wave oscillator, wire grid polarizers, Golay cell detector) to enable operation at Terahertz frequencies while maintaining measurement reliability through proper component selection and system configuration
2Ease of operation
If Terahertz ellipsometry is practiced without commercial systems, then research can proceed, but system configuration and control become difficult
Solution Approach 1:
The patent creates a universal Terahertz ellipsometer system configuration that can be adapted to different Terahertz frequency ranges and application requirements. The system uses standard Terahertz components (backward wave oscillator, wire grid polarizers, Golay cell) that can be configured for various measurements, reducing operational complexity while maintaining versatility
Solution Approach 2:
The patent divides the Terahertz ellipsometer system into distinct functional modules (radiation source, polarizer, sample stage, detector) that can be independently configured and controlled. This segmentation simplifies system operation by allowing each component to be optimized and controlled separately while maintaining overall system coherence
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
This system enables the determination of physical and optical properties of samples using Terahertz frequency electromagnetic radiation, providing a practical solution for Terahertz ellipsometry and polarimetry applications by controlling the polarization state and angle of incidence, thus overcoming the limitations of existing systems.
Implementation Method 1
a backward wave oscillator; a frequency multiplier
Implementation Method 2
a first rotatable polarizer comprising a wire grid; a second rotatable polarizer comprising a wire grid
Implementation Method 3
a first rotating element (RE1), (eg. a wire grid polarizer (RWGP)); a second rotating element (RE2), (eg. a retarder comprising first, second, third and fourth elements (RRET))
Implementation Method 4
a Golay cell detector
Data Source
Figure 1a
Figure 1a'~1b
Figure 1c~1d1
AI summary
A terahertz ellipsometer, the basic preferred embodiment being a sequential system having a backward wave oscillator (BWO); a first rotatable polarizer that includes a wire grid (WGP1); a rotating polarizer that includes a wire grid (RWGP); a stage (STG) for supporting a sample (S); a rotating retarder (RRET) comprising first (RP), second (RM1), third (RM2) and fourth (RM3) elements; a second rotatable polarizer that includes a wire grid (WGP2); and a Golay cell detector (DET).