The University of Melbourne team, part of the Australian Research Council Centre of Excellence for Transformative Meta-Optical Systems, describe their breakthrough in ACS Photonics.
Previous solenoid beams have been created by bulky special light modulators (SLMs), but the size and weight of these systems prevent the beams being used in handheld devices.
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In a statement chief investigator Ken Crozier said: “This work opens new possibilities for using light to exert forces on tiny objects”
The team hopes the metasurface - a layer of nanopatterned silicon around 1/2000 of a millimetre thick - could eventually be used to non-invasively take biopsies.
Beams of light tend to exert a pushing force, moving particles away from the light source, but solenoid beams have been proven to draw particles toward the light source.
This triple helix solenoid beam is claimed to have several benefits over previously generated solenoid beams: the required conditions of the input beam are more flexible than with previous beams, it does not require an SLM, and the size, weight and power requirements are significantly less than previous systems.
The metasurface was created by mapping the phase hologram of the desired beam. This was used to create a pattern. The metasurface was then fabricated from silicon using electron beam lithography and reactive ion etching.
When the input beam - a Gaussian beam - filters through the metasurface, most of it (approximately 76 per cent) is converted into a solenoid beam and bends away from the unconverted beam, allowing the researchers to work with it without obstruction. They were able to characterise the beam at a distance of 21cm.
Lead researcher Maryam Setareh said: “The compact size and high efficiency of this device could lead to innovative applications in the future. The ability to pull particles using a metasurface might have the potential to impact the field of biopsy by potentially reducing pain through less invasive methods.
“We are excited to investigate the performance of our device in particle manipulation, which could offer valuable insights.”
Crozier said the next stage of this research will be to experimentally demonstrate the beam’s ability to pull particles.
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