Hyperspectral Imaging via Optical Time-Stretching and Two-Photon Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing infrared hyperspectral imaging technologies are limited by low spectral resolution and detection sensitivity, restricted by traditional light splitting devices and semiconductor detectors, which hinder their application in fast and non-contact infrared spectral imaging and detection.
Innovation Solution
A hyperspectral imaging method and apparatus utilizing non-degenerate two-photon absorption technology with silicon-based cameras, combined with optical time-stretching and long-wave pump light pulses to enhance spectral resolution and sensitivity, overcoming the limitations of traditional detectors and light splitting methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional infrared focal plane array detectors and spectral dispersion devices are used, then infrared hyperspectral imaging can be achieved, but the spectral resolution and detection sensitivity are limited
Solution Approach 1:
The patent replaces traditional mechanical spectral dispersion devices (prisms, gratings) and infrared focal plane array detectors with a nonlinear optical sampling system using silicon-based cameras. The system uses optical time-stretching to disperse spectra in time domain and non-degenerate two-photon absorption for detection, achieving nanometer-level spectral resolution without complex infrared detectors
Solution Approach 2:
The patent transforms the detection approach by changing from direct infrared detection to indirect detection via non-degenerate two-photon absorption. By using ultrashort pulse laser with high peak power and optical time-stretching, the system converts spectral information into time-domain signals that can be detected by mature silicon-based cameras, dramatically improving spectral resolution to 10^-4 nm level
2Measurement precision
If traditional spectral dispersion and split methods are used, then infrared imaging can be obtained, but the detection sensitivity is insufficient for trace analysis
Solution Approach 1:
The patent employs periodic ultrashort pulse laser illumination with repetition rates of several kHz to illuminate the sample. The optical time-stretching process periodically maps different spectral components to different time delays, enabling high-speed spectral acquisition. This periodic action allows the system to achieve both high detection sensitivity and fast acquisition speed, suitable for real-time trace analysis
Solution Approach 2:
The patent replaces slow mechanical scanning spectral devices with a parallel optical time-stretching system. All spectral components are simultaneously dispersed in time domain and detected by the silicon-based camera in parallel, achieving acquisition speeds of several frames per second while maintaining high detection sensitivity for trace substance analysis
3Measurement precision
If conventional detectors are used, then imaging can be performed, but the spectral resolution cannot reach nanometer level
Solution Approach 1:
The patent converts spectral dispersion from spatial domain to time domain through optical time-stretching. The ultrashort pulse laser with duration of hundreds of femtoseconds to picoseconds provides a time window that, when stretched by dispersive elements, maps spectral frequencies to arrival times. This dimensional transformation enables nanometer-level spectral resolution (10^-4 nm) while maintaining fast acquisition speed, as all spectral information is captured simultaneously in a single camera exposure
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 solution achieves significantly improved spectral resolution of 10−4 nm and enhanced detection sensitivity, enabling high-performance infrared hyperspectral imaging with flexible wavelength selection and reduced acquisition time, suitable for applications like histopathological diagnosis and trace analysis.
Implementation Method 1
subjecting the signal light to optical time-stretching to broaden a pulse width of the signal light and separate light components of different wavelengths in the signal light in the time domain
Implementation Method 2
detect the signal light through non-degenerate two-photon absorption of the signal light thereon under the action of the pump light
Data Source
AI summary
A hyperspectral imaging method includes: providing time-domain synchronous mid-infrared ultrashort pulse and near-infrared ultrashort pulse as pump light and signal light, respectively; subjecting the signal light to optical time-stretching to broaden a pulse width of the signal light; directing the time-stretched signal light to a target sample to be detected; directing the pump light to a time delayer to adjust the time when the pump light reaches a silicon-based camera; spatially combining the time-stretched signal light from the target sample with the pump light from the time delayer; directing combined light to a silicon-based camera where the signal light is detected through non-degenerate two-photon absorption of the signal light under the action of the pump light to acquire hyperspectral imaging data; and obtaining an image of the target sample based on the hyperspectral imaging data.