Available Photonics Experiments:

P5852 Laser safety
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  • Pulsed Diode and DPSS laser
  • Beam divergence
  • Laser energy and power
  • Laser intensity
  • Laser scattering
  • Laser classification
  • Determine safety goggles
  • Examples of investigations and measurements
LAM Laser can emit dangerous radiation. To protect against any injure international safety rules are like IEC 60825 or ANSI Z136 are created and strictly applied. The lasers are classified into different classes with the individual maximum permissible exposure limit (MPE) which is defined as intensity, power per square centimetre (W/cm2). Under no circumstances this intensity should be exceeded. To classify a laser one needs to know its intensity in order to compare it with the MPE values. For pulsed laser its energy is used instead of the power of continuous wave (cw) laser. Within this experiment one pulsed and one cw laser are classified. For this purpose the intensity needs to be determined. To calculate this value the power, the beam diameter and the beam divergence are measured. For the pulsed laser its repetition rate and the emitted energy is measured.
OX Measuring the laser power or energy
To measure the laser power a calibrated sensor head (11) is used in conjunction with the display (10). The particular laser is placed onto the rail (8) and the sensor in front of it. Once the emitted power or energy is measured the repetition rate of the pulsed laser is measured by means of the photodetector which is connected to the oscilloscope along with the 50 ohms shunt resistor.
OX Measuring beam diameter and divergence
The beam of the laser is expanded by a concave lens (2) with known focal length. The expanded intensity profile is measured by using the photodetector (1) which is mounted to the swivel arm of (14). The measurements are repeated for different positions of the expanding lens. The respective position is noted by reading the scale of the optical rail. Out of this measurements and related plots of the intensity distribution the beam diameter and divergence without the lens (2) is calculated.
The intensity of the probe laser can now be calculated and compared to the related MPE value.
OX Laser light scattering
The laser safety rules are not only concerned about direct laser beams but also about scattered laser light which intensity might become hazardous.
To evaluate this situation the angular resolved intensity distribution of the scatter probe is measured. For this purpose the probe (16) is placed under a certain angle with respect to the incident laser beam. The maximum intensity is located and the intensity value determined and compared with the NOHD values for diffuse radiators.
OX Measuring filter transmission
According to the safety rules the user must wear safety goggles in case it cannot made sure that direct exposition to the laser beam is impossible. In principle such goggles are optical filters with specific properties. One important one is the optical density (OD) for a specific wavelength.
The kit comes with one filter (3) which optical density is measured by using the cw as well as pulsed laser.
  • P5852 Laser safety consisting of:
12B-05401Photodetector for pivot arm
24B-00901Biconcave lens f=-10 mm, C25 mount
34F-00041Coloured glass filter BG39, 50 x 50 x 3 mm
4ED-00101Adaptive power supply APS-05
5ED-00901Pulsed laser diode controller PLDC-01
6LS-01101DIMO diode laser module, 532 nm
7LS-13101Pulsed diode laser in housing
8MC-00061Profile Rail OCM 650, 500 mm with ruler
9TP-00301Digital multimeter 3 1/2 digits
10TP-00421Laser power meter LabMax-TO
11TP-00481LM-2 VIS power sensor 50 mW / 1 nW
12TP-00501Laser energy sensor head 300 nJ - 600 �J
13XM-01901Plate holder on carrier 20
14XM-02101Triple swivel unit
15XM-10903Mounting plate C25 with carrier 20 mm
 Required Options:  
 TP-01001Oscilloscope 100 MHz digital, two channel