3 ms·
I will be pedantic but there is no light at 4000nm. Light is by definition the radiation that is considered from the point of view of its ability to excite the
by kelsolaar 7y ago
I will be pedantic but there is no light at 4000nm. Light is by definition the radiation that is considered from the point of view of its ability to excite the human visual system (HVS). The HVS sensitivity, as given in ASTM E308-15 practise, is in range [360, 780]nm.
- datenwolf 7y agoWell, the semantics of what constitutes light and what not are a bit murky. CO2 lasers are still considered LIGHT amplification by stimulated emission of radiation. CO2 lasers operate at ~10000nm. In the optics community we usually consider everything we can manipulate with refractive optics as "light" – and yes, I am fully aware that this goes down well into what's considered microwave radio. My personal cutoff for where optics begins is, where I no longer can use an antenna that is part of a resonant _circuit_ to emit / receive the radiation, and have to resort to quantum mechanical state transitions.