We describe a microwave-optical double resonance experiment designed for Stark effect measurements on molecules in excited vibrational energy levels of ground electronic states. This technique, which employs pulsed laser excitation and laser induced fluorescence detection, has been used to measure electric dipole moments in the 1(1), 5(1), and 5(2) vibrational states of formaldehyde. In addition, a Stark induced quantum beat experiment is briefly described. (C) 2003 American Institute of Physics.