Pump-Probe VUV Spectroscopy Without Large Diffraction Optics
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Solution Overview
Problem
Current spectroscopic measurement apparatuses face challenges in achieving high energy resolution in the vacuum ultraviolet region due to limitations in optical elements and the need for large spectrometers and high-intensity light sources, making laboratory-based measurements difficult.
Innovation Solution
A compact spectroscopic measurement apparatus utilizing a pulsed laser light source, beam splitter, delay circuit, chopper, wavelength converter, and detector to perform pump-probe spectroscopy with ultrashort pulsed VUV light, enabling high energy resolution without relying on synchrotron radiation facilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dispersion type apparatus with a diffraction grating is used to achieve high energy resolution in the VUV region, then the energy resolution is improved, but the apparatus size becomes large and requires a large spectrometer
Solution Approach 1:
The patent replaces the mechanical diffraction grating system with an interferometric system using a Michelson interferometer. This substitution eliminates the need for large dispersive optics while achieving high energy resolution through interference patterns, directly resolving the contradiction between resolution and apparatus size in the VUV region
Solution Approach 2:
The patent changes the measurement approach from direct spectral dispersion to time-domain interferometry followed by Fourier transformation. By measuring interference patterns as a function of path difference and transforming to frequency domain, high energy resolution is achieved without requiring large physical dimensions
2Illumination intensity
If synchrotron radiation facilities are used to provide high-intensity VUV light sources, then the light intensity is improved, but the accessibility and ease of operation become poor due to facility requirements
Solution Approach 1:
The patent replaces synchrotron radiation facilities with a table-top laser-based VUV light source system. By using high-harmonic generation from femtosecond laser pulses in a gas medium, the system generates intense VUV light in a compact configuration that can be operated in standard laboratories, dramatically improving accessibility
Solution Approach 2:
The patent uses a gas jet (e.g., noble gas) as a temporary, easily replaceable medium for high-harmonic generation. This disposable gas supply system replaces the need for expensive, permanent synchrotron infrastructure, enabling high-intensity VUV light generation in accessible laboratory settings
3Device complexity
If conventional optical elements are used in the VUV region, then the optical system is simplified, but the available optical elements are limited and manufacturing precision becomes difficult to achieve
Solution Approach 1:
The patent replaces conventional VUV optical elements (mirrors, lenses, gratings) with a gas-based high-harmonic generation medium. This substitution eliminates the need for precision-manufactured VUV optics, as the gas jet serves as a temporary, easily replaceable optical element that requires no precision manufacturing
Solution Approach 2:
The patent changes the state of the optical medium from solid/optical elements to gaseous medium. By using gas jets for high-harmonic generation and detection, the system avoids the manufacturing precision challenges of VUV optical components while maintaining system functionality
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 energy resolution spectroscopic measurements in the VUV region within a laboratory setting, miniaturizing the apparatus and eliminating the need for large spectrometers and high-intensity light sources, while maintaining sensitivity through boxcar integration and lock-in detection methods.
Implementation Method 1
a wavelength converter that wavelength-converts the second light into vacuum ultraviolet light
Implementation Method 2
a chopper that intensity-modulates the first light
Implementation Method 3
a detector that detects the second light reflected by the sample or the second light transmitted through the sample
Data Source
AI summary
A spectroscopic measurement apparatus includes a pulsed laser light source that emits pulsed laser light, a beam splitter that splits the pulsed laser light into pump light and probe light, a delay circuit that changes a delay time of the pump light with respect to the probe light, a chopper that intensity-modulates the pump light, a wavelength converter that wavelength-converts the probe light into vacuum ultraviolet light, an optical system that guides the pump light and the wavelength-converted probe light to a sample, and a detector that detects the probe light reflected by the sample.