Move aside Harry Potter, science has invisibility cloaks too. The non-magical version was inspired by polar bear fur and works by having, excellent thermal insulating properties. Polar bear hair has a hollow core which effectively prevents the infrared emission, or heat signature, of the polar bear from escaping the fur. This helps the bear retain its heat and stay warm. Because of this efficient reflection of … Continue reading Scientists make a polar bear-inspired invisibility cloak
In a rainbow, the shortest visible wavelength of light is approximately 400nm (blue) and the longest 700nm (red), where all others colors outside this range are invisible to humans.
Except not quite. Artal et. al. demonstrate that the eye’s visual acuity for infrared light (1000nm), is almost the same as for visible green light. The exploited effect in the eye converts two-invisible photons into a single visible one. Importantly, this demonstrated sensitivity to infrared light could enable future ophthalmic devices to help patients with eye conditions, such as cataracts, that make them opaque to visible light. Continue reading It takes two to see (infrared photons anyway)