Principle of operation

A bank of five lasers (L1 to L5) is arranged in such a way, that the moveable beam bending mirror (S1) selects the beam to be measured. In front (P2) of each laser different modules can be placed to manipulate the beam properties as divergence or beam diameter. Other target modules as the simulator for human eye, attenuator etc. can be placed into the path P1. For the measurement of angular dependant parameters of scattering surfaces the rotatable holder S2 is used. The power meter head (PM) can be placed at various positions of interest.
In this experiment the students are required to convert the essential theoretical contents regarding €žLaser Safety€œ into practice. The application and use of the basics in calculation defined within the standards is introduced and trained by means of practical examples. The experiment is composed of five segments:
1. Determination of the maximum permissible radiation (MPR) for skin and eyes.
2. Minimum safety distance from a radiation source for direct and indirect irradiation of the skin and the eyes (MSD).
3. Demonstration of the damaging effect of laser radiation.
4. Characterisation of pulsed laser systems.
5. In addition the experiment is supposed to generate a sensitivity for the dangers of laser use.
The fundamentals of VBG, EN 60825 or corresponding literature of laser safety must be known. The danger of lasers are understood by the characteristic properties of laser radiation. In comparison with other light sources, a high energy and power density can be obtained, because of the generally small beam divergence the radiation density can be very high even at large distances from the laser (potential danger of lasers used in metrology).
Not only direct radiation but also reflected and scattered radiation can cause damage at a large distance from the radiation source. Laser radiation can be generated within a broad spectral range.
The damage of biological tissue (skin, eyes) is of great importance under safety aspects when classifying lasers and fixing radiation limits. By means of five different laser sources, all parameters are measured in order to classify each laser and to determine the limits for which the laser can be considered as save. This also includes the characterisation of laser safety goggles.