(Speaking) With LASIK,doctors use a laser to permanently change the shape of the cornea to improve vision.

VOA: standard.2010.03.03

And then since we have my red laser pointer, we will also try with the red laser pointer, which is centered at wavelength of 700 nanometers.

然后因为我们有我的红色激光笔，我们也可以用它试一下，它的波长集中在700纳米处。

麻省理工公开课 - 化学原理课程节选

So what we end up with for the number of photons in this laser beam of light is 2.1 times 10 to the 17 photons.

这个激光束的数目是,2，1乘以10的17次方。

麻省理工公开课 - 化学原理课程节选

Because of their unique surface, each medal is struck with 12 dies nine times with 1,900 tons of pressure, the weight of more than The native designs were laser-engraved on each medal.

VOA: standard.2010.02.16

Also, what's the energy per photon of this red laser pointer, and then it's also worth trying a calculation dealing with intensity. So let's also try calculating the numbers of photons that would be emitted by this laser pointer, if, for example, we were to use it for 60 seconds and this were a one milliwatt laser.

同样，红色激光笔的,每个光子能量是多少，这也值得用处理强度的方法计算一下,让我们也计算一下,有多少光子会从这个激光笔射出，举个例子，如果我们使用它持续60秒,这里会有一毫瓦的激光。

麻省理工公开课 - 化学原理课程节选