An idea of piShaper operation is illustrated
at the picture below. Gauss intensity distribution of TEMoo laser beam
is converted to a flat-top distribution (similar to a Greek letter
π) that stays invariable for a long distance.
the technology of energy conversion make it possible to create almost
arbitrary intensity distribution of output beam providing adaptation
to a particular application. However, very often just flat-top distribution
is required, that is why as a standard the piShaper provides
A main benefit from using piShaper is saving
of laser energy that is very important in many laser applications, especially
in material processing. The problem is that Gauss intensity distribution
isn't an optimum one in many cases. For example, while materials treating
a great part of energy concentrated far from a middle of TEMoo laser
beam is not used to get a proper treating effect, most often it is considered
as a loss of energy. From this point of view evaluation of the efficiency
of using laser energy has a great importance.
As a first approach it could be done with taking into account
geometrical issues only, without effects accompanying laser treatment
of materials like burning, etc. At a figure below one can see Gauss
intensity distribution in a section of laser beam where Ih is a level
of energy when an effect of material treatment happens. "The energy
figure" of laser beam has three parts:
- E1 - an apex
of Gauss is an excess of energy over the working level Ih,
- E2 - "tails"
of Gauss that almost always are losses of energy, and
- E3 - effective
"cylinder" of energy.
Results of calculations for "parts of energy" are presented
at right figure.
results seem to be very interesting. The unconditional energy loss E2,
"tails", can reach very high level, for example, if a working energy
level is a half of maximum (very often just this level is considered
as a working one) the energy losses are 50% of full laser beam energy!
In case of laser technologies of treatment of thin films
of material the energy part E1, "apex of Gauss", is also considered
as a loss of energy since this part exceeds the working energy level
Ih, thus both energy parts E1 and E2 represent losses.
Sum of losses E1 + E2 is shown as a graph at the diagram
as well; minimum of this function is 0,63. In other words, when treating
of thin films in the best case "only" 63% of energy is lost and 37%
Sure, this is geometrical interpretation only, however
this approach makes it possible to evaluate amount of losses of laser
radiation, they could reach, sometimes, a half of total laser energy!
While applying technologies of beam shaping it is possible to improve
substantially the efficiency of using the laser energy, as well as to
reach some additional effects of laser materials treatment.
publication about energy saving is here(PDF, 141 KB).