Hole burning in the optically detected zero-field spectrum using eedor

Using EEDOR, hole burning is demonstrated in the optically detected zero-field spectrum of tetrachlorobenzene in durene at 1.6°K, thus providing evidence that a large contributor to the width in these spectra is inhomogeneous broadening. Using phase sensitive detection in conjuction with EEDOR, a highly resolved optically detected microwave spectrum of a selected narrow distribution of molecules dissolved in a host is recorded. The potential use of this technique in eliminating inhomogeneous broadening from the phosphorescence-microwave double resonance spectrum is indicated.