We utilize ultrafast optical measurement to study the quasiparticle relaxation in stoichiometric LiFeAs and nearly optimally doped (BaK)Fe2As2 crystals. According to our temperature-dependent studies of LiFeAs, we have observed pseudogap-like feature
at onset temperature of ~ 55 K, which is above Tc = 15 K. In addition, the onset temperature of pseudogap ~90K was also observed in Ba0.6K0.4Fe2As2 (Tc = 36 K). Our findings seem implying that the pseudogap feature, which is due to antiferromagnetic fluctuations, is universal for the largely studied 11, 111, 122, and 1111 iron-based superconductors.
