Researchers have engineered a novel diffractive optical element capable of performing the fundamental NAND logic operation, paving the way for advanced all-optical computing systems. This innovative approach encodes binary information within the spatial distribution of light, specifically by using pairs of apertures where the relative optical power determines the logical state of ‘True’ or ‘False’.
Unlike previous methods that required additional energy-consuming probe lights and faced challenges in connecting multiple gates, this new design achieves cascadability. The output from one diffractive NAND gate can directly serve as the input for another, enabling the construction of complex optical circuits.
The team developed a four-layered diffractive neural network, trained through computer simulations, to execute the NAND function. They demonstrated the gate’s functionality by numerically testing it with various optical inputs, confirming its accurate operation.
Furthermore, the researchers showcased the practical application of this diffractive NAND gate by building essential logic gates such as AND, OR, and NOT. They achieved this by strategically cascading multiple NAND gates, mirroring the fundamental principles of digital electronic circuits but entirely in the optical domain. They also successfully constructed an all-optical half-adder, a basic arithmetic building block, using five cascaded diffractive NAND gates.
A key aspect of their findings highlighted the importance of a “design map” to navigate potential error points that arise when cascading these optical gates. By understanding these error combinations, it becomes possible to design more reliable and complex all-optical processors.
This development suggests a significant step forward in optical computing, potentially leading to faster and more energy-efficient information processing technologies by harnessing the speed and bandwidth of light.
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