The human eye can only see light at certain frequencies (called the visible spectrum), the lowest of which constitutes red light. Infrared light, which we can’t see, has an even lower frequency than red light. Researchers at the Indian Institute of Science (IISc) have now fabricated a device to increase or “up-convert” the frequency of short infrared light to the visible range.
Up-conversion of light has diverse applications, especially in defence and optical communications, Bengaluru-based IISc noted in a press release.
In a first, the IISc team used a 2D material to design what they call a non-linear optical mirror stack to achieve this up-conversion, combined with widefield imaging capability, it said.
The technology employs multilayered gallium selenide attached to a gold reflective surface with a silicon dioxide layer in between, simplifying existing complex infrared imaging approaches.
This culmination of research was led by Associate Professor Varun Raghunathan from the Department of Electrical Communication Engineering and his team, including PhD student Jyothsna K Manattayil. Their work, published in ‘Laser & Photonics Reviews,’ promises improved efficiency and reduced size, circumventing the limitations and export restrictions of conventional infrared sensors.
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