As the light bounces back and forth, appropriate spacing of the mirrors amplifies a particular colour (wavelength) of light, while cancelling out others.
由于光来回反射，镜子间距适当，就增强了某种特定颜色(波长)的光，同时抵消了其他颜色(波长)的光。
2
When the strain is removed, it forms a ripply surface, and the spacing of the ripples affects the colour of the laser light, which varies as the material is stretched.