New photon-avalanching nanoparticles might allow next-generation optical computer systems
by Theresa Duque for Berkeley Information
Berkeley CA (SPX) Mar 01, 2025
A analysis workforce co-led by Lawrence Berkeley Nationwide Laboratory (Berkeley Lab), Columbia College, and Universidad Autonoma de Madrid has developed a brand new optical computing materials from photon avalanching nanoparticles.
The breakthrough – which the workforce revealed lately within the journal Nature Photonics – paves the best way for fabricating optical reminiscence and transistors on a nanometer measurement scale corresponding to present microelectronics. This method provides a path towards realizing smaller, quicker elements for next-generation computer systems by benefiting from an optical phenomenon known as “intrinsic optical bistability.”
“That is the primary sensible demonstration of intrinsic optical bistability in nanoscale supplies,” mentioned Emory Chan, a employees scientist in Berkeley Lab’s Molecular Foundry and co-lead creator on the examine. “The truth that we are able to reproducibly make these supplies and perceive their unintuitive properties is crucial for making optical computer systems at scale a actuality.”
The work is a part of Berkeley Lab’s broader push to advance smaller, quicker, and extra energy-efficient microelectronics with new supplies and methods.
For many years, researchers have sought methods to make a pc that makes use of mild as an alternative of electrical energy. Supplies with intrinsic optical bistability (IOB) – a property that permits a fabric to make use of mild to modify between two completely different states, reminiscent of glowing brightly or by no means – might function elements for optical computer systems. However in earlier research, optical bistability had nearly solely been noticed in bulk supplies that had been too huge for a microchip and difficult to mass produce. And within the few earlier studies of nanoscale IOB, the method was not properly understood and was assumed to happen by heating the nanoparticles, which is inefficient and tough to manage.
However now, Chan and the workforce’s latest examine means that the brand new photon avalanching nanoparticles might overcome these challenges in realizing IOB on the nanoscale.
Throughout experiments on the Molecular Foundry, a nanoscale science person facility at Berkeley Lab, the researchers fabricated 30-nanometer nanoparticles from a potassium-lead-halide materials doped with neodymium, a rare-earth aspect generally utilized in lasers.
When the nanoparticles had been excited with mild from an infrared laser, they exhibited a phenomenon referred to as “photon avalanching,” during which a small improve in laser energy leads to an enormous, disproportionate improve within the mild emitted by the nanoparticles. The workforce first found this “excessive nonlinearity” of photon avalanching nanoparticles of their pioneering 2021 paper, which demonstrated that doubling the laser energy elevated the depth of the sunshine emitted by 10,000-fold.
Of their newest work, the workforce discovered that their new nanoparticles had been over 3 times extra nonlinear than these authentic avalanching nanoparticles, “the best nonlinearities that anybody has ever noticed in a fabric,” Chan mentioned.
To the researchers’ shock, additional experiments within the present examine confirmed that these nanoparticles not solely exhibit photon avalanching properties when excited above a given laser energy threshold, however in addition they proceed to emit brightly even when the laser energy is decreased under that threshold, and solely flip off fully at very low laser powers. In different phrases, these tiny avalanching nanoparticles turned out to be the IOB that had lengthy eluded nanoscientists.
The big distinction between these “on” and “off” threshold powers implies that there are intermediate laser powers at which the nanoparticles could be both vivid or darkish, relying solely on their historical past, Chan defined. This capacity to modify optical properties with out altering the fabric means that the nanoparticles might function nanoscale optical reminiscence, notably risky random-access reminiscence (RAM).
Looking for the origins of the groundbreaking bistability in these supplies, the researchers then used pc fashions to disclose for the primary time that IOB of their nanoparticles arises not from nanoparticle heating, however relatively from the intense nonlinearity of photon avalanching and from a novel construction that dampens vibrations within the particles.
In future research, the researchers hope to review new purposes for optically bistable nanomaterials and discover new formulations for nanoparticles with higher environmental stability and optical bistability.
The Molecular Foundry is a nanoscale science person facility at Berkeley Lab.
Analysis Report:Intrinsic optical bistability of photon avalanching nanocrystals
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