Multi-Photon Ionization Spectrometer for Solid Assay
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Solution Overview
Problem
Absorption spectroscopy of solids under ambient conditions is hindered by spectral line broadening, making it difficult to identify and assay components due to overlapping spectral lines, which limits its practicality for nondestructive analysis.
Innovation Solution
A multi-photon ionization (MPI) spectrometer using a tunable laser to illuminate a solid with pulses of light at various wavelengths, measuring current generated by ionization processes to produce a dense population of wavelength-resolved features in the MPI spectrum, allowing for the identification and quantification of molecules in solids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If absorption spectroscopy is used to assay solids under ambient conditions, then the method is simple and nondestructive, but spectral line broadening causes overlapping lines making identification difficult
Solution Approach 1:
The patent changes the fundamental measurement parameter from absorption spectroscopy to multi-photon ionization spectroscopy. This parameter change transforms the broad, overlapping absorption lines into narrow, well-resolved ionization lines, enabling precise identification of spectral features while maintaining the simplicity of the assay method under ambient conditions.
Solution Approach 2:
The patent replaces the conventional absorption spectroscopy measurement mechanism with a multi-photon ionization mechanism. By using intense laser pulses to induce non-linear ionization processes, the system achieves high spectral resolution without requiring the complex sample preparation or vacuum conditions that would otherwise be needed.
2Ease of manufacture
If conventional absorption spectroscopy is used on solids, then no special preparation is needed, but spectral lines overlap substantially making analysis impractical
Solution Approach 1:
The patent changes the spectroscopic measurement parameter from linear absorption to non-linear multi-photon ionization. This parameter change produces narrow ionization lines that do not overlap, enabling practical analysis of solids under ambient conditions without sample preparation while achieving high analytical productivity.
3Measurement precision
If multi-photon ionization is used to achieve narrow spectral lines, then spectral resolution is improved, but the process requires intense laser pulses
Solution Approach 1:
The patent uses periodic pulsed laser action to achieve multi-photon ionization. By delivering intense laser energy in short, periodic pulses rather than continuous wave, the system achieves the necessary peak intensities for narrow ionization lines while allowing the sample and system to cool between pulses, managing the energy input effectively.
Solution Approach 2:
The patent changes the laser operating parameter from continuous wave to pulsed mode with high peak intensity. This parameter change enables multi-photon ionization to occur, producing narrow spectral lines with high resolution, while the pulsed nature manages the total energy input to practical levels.
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 the acquisition of absorption spectra for solids under ambient conditions, providing a means to effectively identify and quantify components with improved signal-to-noise ratio and sensitivity, overcoming the limitations of spectral line broadening.
Implementation Method 1
A multi-photon ionization (MPI) spectrometer uses a tunable laser to illuminate a solid with pulses of light at various wavelengths
Implementation Method 2
measuring current generated by ionization processes to produce a dense population of wavelength-resolved features in the MPI spectrum
Data Source
AI summary
A method of assaying a solid or liquid material, the method comprising: illuminating a sample of the material with pulses of light at a plurality of different wavelengths at which atoms and/or molecules in the material are ionized in multiphoton ionization (MPI) process; generating a value responsive to charge produced in the ionization process for each wavelength to provide an MPI spectrum for the material; and processing the MPI spectrum to assay an atom or molecule in the material.