Macroscopic laser pulling based on the Knudsen force in rarefied gas
Optics Express
|February 14, 2023
Summary
Scientists demonstrate laser pulling of macroscopic objects in rarefied gas, overcoming microscale limitations. This optical manipulation technique utilizes Knudsen force for forces significantly larger than radiation pressure.
Area of Science:
- Optics and Photonics
- Materials Science
- Nanotechnology
Background:
- Optical pulling has been demonstrated for micro- and nano-objects.
- Extending optical pulling to macroscopic objects presents significant challenges.
- Existing methods are limited in scale and force magnitude.
Purpose of the Study:
- To demonstrate laser pulling of a macroscopic object.
- To investigate the mechanism of optical pulling at the macroscale.
- To provide a technique for macroscopic optical manipulation.
Main Methods:
- Utilized a Gaussian laser beam to irradiate a macroscopic structure.
- The structure comprised absorptive bulk cross-linked graphene and a SiO2 layer.
- Employed a torsional pendulum for qualitative demonstration and a gravity pendulum for quantitative force measurement.
Main Results:
- Successfully demonstrated laser pulling of a macroscopic object in rarefied gas.
- Identified Knudsen force as the origin of the pulling force.
- Measured pulling forces exceeding radiation pressure by over three orders of magnitude.
Conclusions:
- Expanded the scope of optical pulling from microscale to macroscale.
- Presented an effective technique for macroscopic optical manipulation.
- The Knudsen force provides a viable mechanism for large-scale optical pulling.
