Turning infrared light visible: New device uses 2D material to up-convert infrared light

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.