MULTIPLE PHOTOCHEMICAL HOLE BURNING IN TETRAPHENYLPORPHINE DERIVATIVES USING A FOCUSED LASER-BEAM

The recording properties of photochemical hole burning (PHB) in tetraphenylporphine (TPP) derivatives with a focused laser beam were studied. We demonstrated the possibility of more than 200-multiplicity recording in the frequency domain in tetrakis(pentafluorophenyl)porphine (TFP) in a 10-mu-m-diameter laser spot at 4 K. The effect of the laser irradiation time on the depth was also investigated using tetrakis(4-methoxyphenyl)porphine (TMP). Although the hole depth decreased with decreasing laser irradiation time down to the ms order due to the bottleneck effect (because of long triplet lifetime), a detectable hole is formed with irradiation by a 8 ms pulse using TMP.