Using the characteristic of refractive index are smaller than 1 in the reststrahlen band,we can produce photonic crystal having forbidden band in the middle infrared and far infrared.
It also emits natural phytocide to keep air fresh, and keep people's mind clear, and emit the far infrared ray to improve the blood circulation to relieve the fatigue.
Clouds of dust that look dark to the human eye are actually glowing if you observe them in the far infrared, well outside the colors our eyes can detect.
射率小于1
特性，我们可以制
出中红外区和远红外区存在
，
看到的范围。
色的，
