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Frequency domain approach for time-resolved pump-probe microscopy using intensity modulated laser diodes.
J Miyazaki1, K Kawasumi1, T Kobayashi1
1Advanced Ultrafast Laser Research Center, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan.
The Review of Scientific Instruments
|October 3, 2014
Summary
This study introduces a novel time-resolved pump-probe microscopy technique using modulated laser diodes. It enables high-resolution analysis of ultrafast dynamics in materials and biological samples without specialized equipment.
Area of Science:
- Optics and Photonics
- Materials Science
- Spectroscopy
Background:
- Conventional optical microscopy is limited by diffraction.
- Characterizing ultrafast dynamics (nanosecond to picosecond) often requires expensive, high-speed equipment.
- Nonlinear optical interactions offer potential for enhanced spatial resolution.
Purpose of the Study:
- To develop a cost-effective time-resolved pump-probe microscopy scheme.
- To achieve high spatial resolution for analyzing microscopic sample dynamics.
- To enable characterization of relaxation dynamics in various materials.
Main Methods:
- Utilized intensity-modulated laser diodes for pump and probe beams.
- Employed frequency domain detection with a lock-in amplifier at a beat frequency (15 kHz).
- Varied modulation frequencies up to 500 MHz to probe different timescales.
Main Results:
- Successfully characterized nanosecond to picosecond relaxation dynamics.
- Achieved superior spatial resolution compared to diffraction-limited microscopes.
- Demonstrated utility through time-resolved imaging of fluorescence beads and quantum dots.
Conclusions:
- The developed frequency domain pump-probe microscopy is a versatile tool.
- It offers high spatial resolution and is suitable for analyzing optoelectronic devices.
- The system's low-cost components broaden applications in photochemistry, optical physics, and biological imaging.
