Time-Resolved Circularly Polarized Light Spectroscopy Apparatus
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Solution Overview
Problem
Current methodologies for time-resolved characterization of circularly polarized light (CPL) emission are limited by low signal strengths and prominent artifacts, making it challenging to accurately measure and investigate CPL-active materials.
Innovation Solution
A luminescence spectroscopy apparatus comprising a pulsed laser excitation source, an achromatic quarter-wave plate, a polarization beam splitter, an optical spectrometer, a time-gated intensified charge-coupled device (iCCD), and a controller for electronic gating, enabling high-sensitivity time-resolved CPL measurements by separating emission features based on their time scales.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time-correlated single photon counting is used for time-resolved CPL measurements, then time resolution is improved, but data acquisition rate is limited to approximately 1% of excitation rate due to pile-up effects
Solution Approach 1:
The patent replaces time-correlated single photon counting with an intensified CCD detector system that uses electronic gating instead of statistical photon counting methods. This substitution allows for much higher data acquisition rates while maintaining time resolution, as the gated detector can capture photons across the entire spectral range simultaneously without pile-up limitations.
Solution Approach 2:
The patent introduces a new detection dimension by using an intensified CCD array that simultaneously records both polarization components across the entire spectrum in parallel. This multi-dimensional approach (time + wavelength + polarization) eliminates the need to scan through wavelength points sequentially, dramatically increasing data acquisition rate while maintaining time resolution.
2Measurement precision
If photoelastic modulator with lock-in amplification is used for TRCPL measurements, then sensitivity is improved, but spectral acquisition becomes time-consuming requiring one wavelength point at a time
Solution Approach 1:
The patent merges the detection of multiple wavelength points and polarization components into a single simultaneous measurement using the intensified CCD array. Both orthogonal polarization components are recorded across the entire spectral range in one shot, eliminating the time-consuming sequential scanning process while maintaining high sensitivity through the image intensifier.
Solution Approach 2:
The intensified CCD detector serves multiple functions simultaneously: it detects both polarization components, records the entire spectrum, and provides time resolution through electronic gating. This multi-functional capability replaces the need for separate measurements at each wavelength point, dramatically reducing spectral acquisition time.
3Speed
If photoelastic modulator is used for rapid polarization modulation, then polarization modulation speed is improved, but compatibility with detector readout rate and excitation repetition rate becomes problematic
Solution Approach 1:
The patent replaces the mechanical photoelastic modulator system with an electronically gated intensified CCD detector. The electronic gating provides flexible time resolution without mechanical moving parts, allowing independent control of detection timing that is fully compatible with various detector readout rates and excitation repetition rates.
Solution Approach 2:
The patent introduces dynamic electronic gating that can be independently controlled for each measurement. The gate pulse timing and width are adjustable parameters that can be optimized for each specific experiment, providing adaptability that mechanical modulators cannot achieve due to fixed modulation frequencies and mechanical limitations.
4Ease of operation
If single wavelength point measurement is used for kinetics analysis, then measurement simplicity is improved, but insight into excited-state evolution is limited
Solution Approach 1:
The patent combines measurements at multiple wavelength points into a single simultaneous spectral recording using the intensified CCD array. This allows kinetic analysis to be performed across the entire spectrum at once, providing comprehensive insights into excited-state evolution including wavelength-dependent dynamics, while maintaining operational simplicity through automated multi-wavelength detection.
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 apparatus allows for flexible time-gating and simultaneous recording of orthogonal polarization components, overcoming limitations of low signal and artifact issues, thereby providing high-sensitivity and broadband time-resolved CPL measurements.
Implementation Method 1
a pulsed laser excitation source configured to generate a laser pulse for exciting the sample
Implementation Method 2
a luminescence spectroscopy apparatus for time-resolved characterization of a sample emitting circularly polarized light
Implementation Method 3
an achromatic quarter-wave plate arranged to receive therethrough light emitted by the sample
Implementation Method 4
a polarization beam splitter arranged downstream to the quarter-wave plate
Implementation Method 5
an optical spectrometer arranged downstream to the polarization beam splitter
Implementation Method 6
a time-gated intensified charge-coupled device arranged to receive light from the optical spectrometer and comprising an image intensifier
Data Source
AI summary
A luminescence spectroscopy apparatus for time-resolved characterization of a sample emitting circularly polarized light is described, comprising a pulsed laser excitation source configured to generate a laser pulse for exciting the sample, an achromatic quarter-wave plate arranged to receive therethrough light emitted by the sample, a polarization beam splitter arranged downstream to the quarter-wave plate, an optical spectrometer arranged downstream to the polarization beam splitter, a time-gated intensified charge-coupled device arranged to receive light from the optical spectrometer and comprising an image intensifier, and a controller configured to control a pulse generator to apply a gate pulse to the image intensifier for selectively activating the image intensifier, wherein the controller is connected to the pulsed laser excitation source such that the gate pulse is triggerable by the laser pulse of the pulsed laser excitation source.