By using a short pulse CO2 , tail free , broadband laser it is possible to produce a compressed high power FIR pulse in a pure Raman system when a suitable pressure and Raman cell length are used . In this way we have obtained 4ns (70KW) emission around the sR(3,0) NH3 line pumped by 130 mJ (23ns) 9P20 CO2 line. More resonant transitions can be also compressed at a suitable high pressure also if they show a large optical pumping and cascade processes at low pressure.