Deuterium emission in laser plasma induced by transversely excited atmospheric pressure CO2 laser in low-pressure of helium surrounding gas

A transversely excited atmospheric pressure (TEA) CO2 laser was focused on samples containing hydrogen of high concentration in ambient gas of low pressure. The optimum conditions for reducing the spectral width of H-alpha emission have been investigated. As a result, it was found that a film sample is superior to a bulk sample, and He gas should be used as the ambient gas at approximately 1 Torr, and for spectral measurement, only the front area of the plasma should be selected. We successfully demonstrated the detection of D-alpha emission, of which peak shifts only 0.179 nm from the H-alpha emission, by employing a D2O liquid film sandwiched between a Cu plate and a thin plastic wrapping film.