Experimental study of bi-directional pumping of a far-infrared laser

We show that bi-directional pumping can increase significantly the output power of optically pumped gas lasers. We demonstrate this effect in experiments with a methanol laser pumped by a CO2 laser in a wide range of gas pressure for two different wavelengths, 119 μm and 170 μm. In our experimental conditions we obtain an enhancement of the maximal output power up to 70% as compared with uni-directional pumping of the same total intensity.