As light shines steadily on a silver slip of a fish, minuscule dots on the fish start flashing: blue, yellow, blue, yellow.
The bodies “do not glow like luminous fish,” Masakazu Iwasaka, an interdisciplinary engineer at Hiroshima University in Japan has discovered. Instead of making their own light, it turns out that remarkable little photonic crystals in fish spots reflect certain wave-lenghts of lights alternating between blues and more greenish-yellows, he reports April 7 in Royal Society Open Science.
