Deconvolution of distorted ODMR spectra

With optical detection of magnetic resonance (ODMR), the zero-field splitting of the molecular triplet state can be investigated. When recorded with nonstationary optical excitation, distorted ODMR spectra are obtained, because the true lineshape is convoluted with the triplet decay kinetics. The origin of this distortion is discussed specifically for pulsed optical excitation. As the convolution integral cannot be solved analytically, a straightforward deconvolution procedure (no computer fit) is developed which is based on numerical model calculations. With this procedure, all of the desired information can be extracted from the experimental spectra: the lineshape function (Gaussian against Lorentzian), the true transition frequency and the linewidth.