Optical radiation is just visible light energy spreading out.

光辐射就只是扩散的可见光能量。

youdao

Physical objects, when struck by light (the visible kind, see electromagnetic radiation), will reflect back certain wavelengths of light to your eyes.

一个物体，受到光线照射(可以看得到的物体，见电磁辐射)，将会把某些波长的光反射到你的眼睛里。

youdao

The traditional answer to this question was that most of the sun's radiation is visible light, so our eyes evolved to see those wavelengths.

一般对这一问题的回答是：大多数的太阳光都是可见光，所以我们的眼睛在进化过程中已经形成了选择性偏好。

youdao

I'm looking outside now and that's electromagnetic radiation - visible light.

BBC: NEWS | UK | Magazine | Wi-fi worry

When it is ground into nanoparticles it can still block harmful ultraviolet radiation, but it allows visible light to pass straight though, which means modern sunscreens can appear completely transparent, while offering the same protection as the old white stuff.

ECONOMIST: The risk in nanotechnology

Even something too small to emit visible light will probably give off radio waves and infra-red radiation (Jupiter does).

ECONOMIST: X marks the spot