There's an entire world our eyes miss, hidden in the ranges of light wavelengths that human eyes can't see. But infrared cameras can pick up the secret light emitted as plants photosynthesize, as cool stars burn and batteries get hot. They can see through smoke and fog and plastic. But infrared cameras are much more expensive than visible-light ones; the energy of infrared light is smaller than visible light, making it harder to capture. A new breakthrough by National Science Foundation-funded scientists, however, may one day lead to much more cost-effective infrared cameras -- which in turn could enable infrared cameras for common consumer electronics like phones, as well as sensors to help autonomous cars see their surroundings more accurately. Today's infrared cameras are made by successively laying down multiple layers of semiconductors -- a tricky and error-prone process that makes them too expensive to go into most consumer electronics. The researchers lab instead turned to quantum dots -- tiny nanoparticles just a few nanometers in size. (One nanometer is how much your fingernails grow per second.) At that scale they have odd properties that change depending on their size, which scientists can control by tuning the particle to the right size. In this case, quantum dots can be tuned to pick up wavelengths of infrared light.
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