Considerable improvement in the operating efficiency of a hybrid CO₂ laser has been achieved by increasing the TEM₀₀ mode filling factor in the TEA section. The usage of helium-free gas mixture in the TEA section restricted the width of the glow discharge to the central zone in the interelectrode region allowing the oscillating TEM₀₀ mode to experience a higher gain in the TEA section resulting in an improved performance of the laser.