Ultra-low power ultra-fine nano laser invented

The merging process of BIC under ‘Super BIC’. Before merging (left) just before being merged (middle) after merging (right) [Photo Provided = Park Hong-kyu Korea University]

Ultra-fine nano lasers capable of operating under minimum power level while focusing light into a small space were introduced.

National Research Foundation of Korea (NRF President: Roe Jung-hye) announced that Research team lead by professor Park Hong-kyu of Korea University designed a nano laser which is ten million times efficient than before under joint research with professor Kivshar of Australian National University.

The resonator must be miniaturized in order to eject smaller laser and the performance is evaluated under the criteria of how well it focuses light on a small space. Bound states in the continuum which refers to the state that does not interact with any of the states of the continuum (BIC) is considered as a method of confining light to enable amplification light when needed.

Using this energy state was useless because light could not be effectively trapped when the resonator became smaller. The research team thus devised a ‘Super BIC’ that combines several BIC at the same time.

It is a merge of two charges that do not interact with the surroundings. The possibility of light escaped is erased and also the merger prevents light from leaking even in small sizes.

Researchers successfully implemented the Super BIC laser by creating a square grid structure on a circuit bord and fine-tuning grid holes by 1 nm in an experiment. At 574 nm different BIC merged and Super BIC lasers were formed. BIC merge method was introduced as a new paradigm for laser device design which is 10 million times efficient compared to conventional methods. The merger will not be affected even if the structure becomes smaller or defective so it can be used as a flexible light confinement method.

The research team plans to continue its follow-up research using flexible devices that can secure elasticity and precision in adjustment of grid spacing.

The research was supported by the Ministry of Science and ICT and NRF and was published on the international journal Nature Communications on July 5 2021.

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