A small fragment of plastic wrap (common food wrap) was suspended above a 20X microscope objective. Measured with a Heidenhain apparatus, the thickness of the plastic film is 7.2 ± 0.2 μm. This correlates with ~ 30 % of the collection/excitation focal volume depth of the objective, which is ~ 25 μm along the z-axis.
Figure 1 shows the plastic film’s Brillouin spectrum. The pump laser signal is not present on the spectrum as it was suppressed successfully by two “Pump Killers” employed in the systems. The Brillouin frequency shift of the plastic film that was measured is 14.39 ± 0.02 GHz.
Figure 1. a) Brillouin frequency shift spectrum of a suspended plastic film. b) Raw sensor image. The time exposure was set to 5 seconds and the number of averages to 5. Image Credit: Lightmachinery
- Thickness: 7.2 ± 0.2 μm
- Material: Plastic wrap to preserve food “Glad Cling Wrap”
- Power at sample: 25 mW
- Pump wavelength: 532 nm
- FWHM of the instrument response: nominal 0.9 GHz
- Repeatability of Brillouin shift: highly sample and exposure dependent; < 10 MHz is possible
This information has been sourced, reviewed and adapted from materials provided by LightMachinery.
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