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Rapid wavelength scans over one octave and application to laser-induced fluorescence
Joachim W Walewski1, Scott T Sanders
1Department of Mechanical Engineering, University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706, USA. walewski@erc.wisc.edu
Optics Letters
|October 4, 2005
Summary
Researchers demonstrate rapid laser-induced fluorescence (LIF) excitation scans using broadband light generated in photonic crystal fiber. This technique enables fast, spectrally resolved LIF scans, approaching the limits of molecular excited-state lifetimes.
Area of Science:
- Spectroscopy
- Laser Physics
- Materials Science
Background:
- Laser-induced fluorescence (LIF) is a powerful technique for molecular analysis.
- Traditional LIF excitation scans can be time-consuming, limiting applications requiring high temporal resolution.
- Developing faster scanning methods is crucial for dynamic processes and high-throughput screening.
Purpose of the Study:
- To demonstrate a novel method for rapid excitation scans in laser-induced fluorescence.
- To achieve spectrally and spatially resolved LIF measurements at high speeds.
- To explore the potential of photonic crystal fibers for ultrafast spectroscopic applications.
Main Methods:
- Broadband light generation using a photonic crystal fiber.
- Exploiting group-velocity dispersion in a long optical fiber to create a time-varying wavelength sweep.
- Exciting LD 700 Perchlorate dye in methanol with the generated broadband light for LIF measurements.
Main Results:
- Achieved wavelength sweep over approximately one octave in approximately 150 ns.
- Demonstrated LIF excitation scans with a spectral resolution of approximately 15 nm.
- Integrated fluorescence spectrum closely matched the integrated absorption spectrum (within 7%) of the dye molecule.
Conclusions:
- The presented method enables rapid, spectrally resolved LIF excitation scans.
- Scanning speeds are limited primarily by the excited-state lifetime of the target molecule.
- This technique opens possibilities for time-resolved molecular analysis in various scientific fields.