21. Speak about the use of lasers in the following spheres:
Ø home appliances
Ø industry
Ø scientific research
22. You are a guest speaker at the conference devoted to the problems of lasers. Watch the video film about lasers.While speaking about types of lasers their components and the main principle of work, the main fields of laser
application use new information from the film and additional texts. Concentrate not only on the scientific aspects, but on the benefits one can get from the use of lasers. Express your point of view: if lasers can be dangerous and what the possible ways of reducing the danger are. This plan of the film may help you to prepare this report:
The stimulated emission of light was a discovery by Einstein around 1916. All we need is an atom, which possesses electrons just like any other atom in our world and a photon, that is: a quantum of light.
1. Energy levels of atoms and electrons
2. Absorbing energy in the form of photons
3. Stimulated and spontaneous emission
4. Photons with same phase, frequency, polarization, direction
5. Parts of a LASER device (reflectors, gain medium)
6. Chain reaction for coherent and monochromatic light
7. Population inversion (ground state vs. excited state)
LANGUAGE PRACTICE
23. Read and translate the texts “Types of lasers” and “Laser applications ”
