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Experimental analysis of submicrometer optical intensity distributions after an opaque disk
Applied Optics
|April 1, 2020
Summary
Researchers observed a 120 nm laser spot, a subwavelength beam size, using diffraction from an absorbing disk. This Arago spot has minimal size variation and enables applications like atom lithography and spectroscopy.
Area of Science:
- Optics and Photonics
- Nanotechnology
Background:
- Achieving subwavelength beam sizes is crucial for advanced applications.
- Diffraction phenomena offer pathways to manipulate light at the nanoscale.
Purpose of the Study:
- To report the generation and characterization of a 120 nm laser spot.
- To explore the potential applications of subwavelength beams and hollow beams.
Main Methods:
- Utilizing the diffraction of laser diode light by an absorbing disk to create an Arago spot.
- Characterizing the laser spot size and its variation along the propagation axis.
Main Results:
- Observed a 120 nm laser spot, a subwavelength feature.
- Demonstrated less than 10% size variation over 50 µm propagation distance.
- Evidenced hollow beams with a 400 nm central dark spot carrying orbital angular momentum.
Conclusions:
- The generation of subwavelength laser spots is feasible using simple diffraction setups.
- The demonstrated Arago spots and hollow beams have potential applications in atom lithography and spectroscopy.
