In order to understand the laser device we have to focus the main features of the laser emission:

  • Monocromaticity: All the photons emitted has the same frequency
  • Coherence: The emitted wave has ever the same phase in each its part.
  • Directionality: The emitted wave has a very well defined direction with very little spreading
  • Brilliance: The emitted power over surface unit and solid angle is very high 
  • Short impulse: The light emitted may have a very short duration

The Monochromatic feature of the laser is perhaps the more important one. It has several important application in biotechnology. For example it allows to transfer power only to the selected tissue. In order to do soe only need to choose a laser device which has the emission frequency in the range where the biological tissues are sensitive (i.e. a ). 

The Coherence and Directionality allow to focus strictly on the selected position.

The Brilliance enhance the transfer of power to the tissues.

The Short impulse allows to avoid to transfer too much energy to the tissues.

In the exercises with AR the student will build a laser device choosing the right constructive elements in order to achieve the desidered outputs.