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Comparison of active and passive methods for the infrared scanning near-field microscopy
- Source :
- Applied Physics Letters. 114:153101
- Publication Year :
- 2019
- Publisher :
- AIP Publishing, 2019.
-
Abstract
- We systematically compare the active and the passive methods for infrared scattering-type scanning near-field optical microscopy (s-SNOM). The active SNOM makes use of IR lasers or incoherent thermal emitters to illuminate a sample, whereas the passive method directly measures extremely weak fluctuating electromagnetic evanescent fields spontaneously generated at the sample surface without any external illumination. For this reason, our specific version of the passive SNOM is called a scanning noise microscope (SNoiM). In thermal equilibrium, the two methods are shown to be similar, both mapping the nanoscale variation of the complex dielectric constant of the sample. We demonstrate that a significant difference between the two methods emerges when the sample is driven out of thermal equilibrium, viz., the active SNOM is insensitive whereas the SNoiM is extremely sensitive to the electron temperature in locally heated nanoregions.
- Subjects :
- 010302 applied physics
Thermal equilibrium
Materials science
Microscope
Physics and Astronomy (miscellaneous)
Infrared
business.industry
Physics::Optics
02 engineering and technology
Dielectric
021001 nanoscience & nanotechnology
Laser
01 natural sciences
law.invention
Optics
Optical microscope
law
0103 physical sciences
Near-field scanning optical microscope
0210 nano-technology
business
Noise (radio)
Subjects
Details
- ISSN :
- 10773118 and 00036951
- Volume :
- 114
- Database :
- OpenAIRE
- Journal :
- Applied Physics Letters
- Accession number :
- edsair.doi...........09b7975444ed6bea30c3752107287d93