When monitoring laser beams, any measurements must be carried out during the laser process without affecting the beam. It is imperative that the measurement beam is absolutely identical to the processing beam to ensure a realistic reading.
One innovative option is the use of a diffractive beam sampler to separate a small fraction of the main beam’s energy. The benefit is that the beams that are coupled out are a perfect copy of the original beam. Multiple beams allow power measurements and beam profile measurements to be carried out simultaneously.
How it works: the diffractive optical element (DOE) is inserted into the path of the collimated beam. Approximately 99% of the main beam is transmitted through the DOE without changing; the other 1% of the beam intensity is split into higher orders for measurement purposes. The majority of this will go to the first order at a specified angle with subsequent orders receiving smaller fractions at wider angles.
The sampled beams are special as the intensity does not depend on the polarisation of the laser; therefore the samples are completely identical to the main beam.
Product range: large selection of standard elements available, as well as custom or ‘semi-standard’ designs for the wavelength range 193 nm - 10.6 µm.
