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Evanescent Field Based Photoacoustics: Optical Property Evaluation at Surfaces
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Transfer function and near-field detection of evanescent waves
Ilya P Radko1, Sergey I Bozhevolnyi, Niels Gregersen
1Department of Physics and Nanotechnology, Aalborg University, Aalborg, Denmark. ilya@physics.aau.dk
Applied Optics
|June 9, 2006
Summary
This study characterizes near-field optical probes by measuring detection efficiency for propagating and evanescent fields. A simple transfer function approximation accurately models experimental and simulation data for reliable fiber probe characterization.
Area of Science:
- Optics and Photonics
- Nanotechnology
- Materials Science
Background:
- Near-field optical microscopy enables sub-wavelength imaging.
- Characterizing fiber probes is crucial for accurate near-field measurements.
- Understanding the detection efficiency of spatial frequencies is key.
Purpose of the Study:
- To characterize near-field optical probes based on detection efficiency.
- To investigate the role of spatial frequencies in propagating and evanescent fields.
- To develop a reliable method for fiber probe characterization.
Main Methods:
- Experimental measurement of collected power using a near-field microscope with a fiber tip.
- Numerical simulations employing the eigenmode expansion technique.
- Fitting experimental and simulation data with a derived transfer function.
Main Results:
- Demonstrated reciprocity in collection and illumination modes for fiber tips.
- Measured collected power as a function of spatial frequency and polarization.
- Developed and validated a transfer function approximation for probe characterization.
Conclusions:
- The developed transfer function approximation provides a reliable method for near-field fiber probe characterization.
- The approximation effectively fits experimental and simulation data for evanescent fields.
- This work contributes to the precise understanding and application of near-field optical techniques.
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