Search for photoinduced absorption in charge-density-wave materials with non-half-filled bands

We describe experiments to search for photoinduced absorption (PA) due to midgap soliton states in quasi-one-dimensional charge-density-wave materials with band filling N/M 1/2. Experiments were done on trimethyl-ammonium-iodide- tetracyanoquinodimethane (N/M=1/3), K0.3MoO3 (N/M=3/4), and TaS3 (N/M=1/4). Both spectroscopic and broadband searches were made for PA signals. In all cases, no PA was observed. The results are interpreted in terms of the probabilities of formation and lifetimes of soliton states.