Close-Packed Arrays of Plasma Jets Emanating From Microchannels in a Transparent Polymer

Close-packed arrays of microplasma jets, propagating into atmospheric air with uniform plume length and luminosity, have been generated in cylindrical microchannels and characterized. Arrays as large as 8 x 8 with a packing density of similar to 160 cm(-2) have been demonstrated to date. Fabricated in a molded flexible polymer that is transparent deep into the ultraviolet (lambda greater than or similar to 250 nm), microchannel devices less than or similar to 350 mu m in diameter generate plasma in He feedstock gas with a backing pressure of 760-900 Torr and flow rates up to 4.6 standard liters per minute. Chemical kinetics of the He (2(1,3)S) and He 2 (a(3)Sigma(+)(u)) excited species interacting with laboratory air has been examined by optical emission spectroscopy. The maximum jet length for a 5 x 5 array is 3.8 +/- 0.2 mm when the He backing pressure is 840 +/- 20 Torr. Relative to previous jet array designs, this technology increases the jet packing density by more than an order of magnitude and yet jet-jet interactions are not observed.