Intense Stark resonance absorptions near 10.7 &mgr;m of theR(18) andR(24) lines and a weaker absorption of theR(26) line of the isotopic C13O216laser by N14H3are reported. Wideband modulation experiments with an N14H3Stark cell and theR(18) line are presented. Key modulation features are the 2‐ns rise time, high modulation depths, low power dissipation, short Stark modulator cell (10 cm), high saturation intensity (≳8 W/cm2), new spectral features of the modulated signal versus Stark bias, and a demonstration of 180‐Mbit random word modulation.