CO2 Laser

We use a Coherent DEOS GEM select 100 single mode CO2 laser. The laser emits a 100 W horizontally polarised beam

Principle of Operation

Briefly, there is a mixture of CO2, N2 and He gases contained between electrodes in the gain region of the cavity. An RF field is applied between the electrodes which creates a discharge. The first vibrational mode of the N2 molecules (which has a very large excitation cross-section) is excited. This state is metastable and close in energy to the first asymmetric stretch mode of the CO2 molecules. The CO2 molecules are excited due to collisions with the N2 (collisions are augmented by the presence of the He). The first asymmetric stretch mode of the CO2 molecules decay to the first symmetric stretch mode, resulting in laser output at a wavelength of 10.6 Ám.

Content © K. J. Weatherill , Durham University 2005