Supercontinuum Generator for Multi-Wavelength Laser Acoustics
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Solution Overview
Problem
Existing opto-acoustic metrology techniques, such as picosecond ultrasonics, are limited by the fixed wavelength of laser light sources, which restricts their applicability to various materials with different optical properties.
Innovation Solution
The use of a laser light source that generates pulsed light with a first wavelength, combined with a supercontinuum generator that spectrally broadens the pulsed light, allows for the generation of pump and probe pulses with different or the same wavelengths, enabling more versatile material characterization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed wavelength laser light source is used in opto-acoustic metrology, then the device complexity is reduced and ease of operation is improved, but the adaptability to various materials with different optical properties deteriorates
Solution Approach 1:
The patent implements a supercontinuum generator that converts a single wavelength laser source into a broadband light source covering multiple wavelengths. This allows the same device to characterize different materials (metals, semiconductors, insulators) by selecting appropriate wavelengths, making the system universal rather than material-specific. The single laser source serves multiple functions by generating pump and probe pulses at different wavelengths simultaneously.
Solution Approach 2:
The patent changes the wavelength parameter of the light source from fixed to variable by incorporating a supercontinuum generator. This enables dynamic adjustment of pump and probe wavelengths to match the optical properties of different materials being characterized, resolving the contradiction between fixed wavelength simplicity and material-specific adaptability.
2Adaptability or versatility
If a supercontinuum generator is added to spectrally broaden the pulsed light, then the adaptability to various materials is improved, but the device complexity increases
Solution Approach 1:
The supercontinuum generator acts as an intermediary component between the simple single-wavelength laser source and the sample. It transforms the narrowband laser light into broadband supercontinuum light, enabling wavelength selection without requiring multiple complex laser sources. This intermediary approach adds controlled complexity only where needed to achieve spectral broadening.
3Measurement precision
If different wavelengths are used for pump and probe pulses, then the measurement accuracy for materials with different optical properties is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
The patent applies local quality by selecting specific wavelengths from the broadband supercontinuum light for pump and probe pulses based on the optical properties of the specific material being measured. For example, certain wavelengths are selected to maximize absorption in metals while different wavelengths are chosen for semiconductors or insulators, optimizing measurement accuracy for each local measurement context.
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 approach enhances the capability of opto-acoustic metrology to characterize a wide range of materials by optimizing the wavelength selection for each sample, improving measurement accuracy and applicability.
Implementation Method 1
a supercontinuum generator that receives the pulsed light having the first wavelength and spectrally broadens the pulsed light
Implementation Method 2
irradiate the target sample with one or more pump pulses to cause transient perturbation in material in the target sample
Implementation Method 3
irradiate the target sample with one or more probe pulses to produce reflected probe pulses that are modulated based on the transient perturbation in the material
Data Source
AI summary
An opto-acoustic metrology device, such as a picosecond laser acoustic metrology device, includes a laser light source that generates pulsed light with a first wavelength and a supercontinuum generator spectrally broadens the pulsed light. A pump arm receives the pulsed light and generates pump pulses to irradiate a target sample to cause transient perturbation in the target sample. A probe arm receives the pulse light and generates probe pulses to irradiate the target sample to produce reflected probe pulses that are modulated based on the transient perturbation in the target sample. The pump pulses and the probe pulses have different wavelengths or the same wavelengths that are selected from the spectrally broadened pulsed light, e.g., using a filter located before the pump and probe arms or within one of the pump or probe arms. A property of the target sample may be determined based on reflected probe pulses.