Ultrafast laser-induced phase transitions in tellurium

Abstract

Ultrafast laser processing of materials, especially metals and semiconductors, is a field of condensedmatter physics and material science that has developed rapidly over the last few years. It has proved to be of considerable interest for both applied and fundamental research for a variety of reasons, which are discussed extensively in the literature. An important application of ultrashort laser pulses is connected with the study of ultrafast phase transitions. In our previous work [1], we experimentally studied ultrafast changes of order of monocrystalline graphite under irradiation by a femtosecond laser pulse using a new experimental technique that exploits the optical anisotropy of the crystal. In this letter, we present the results of a similar study performed on samples of monocrystalline tellurium. The experiments were performed with a chirped-pulseamplified Ti:sapphire laser system (100-fs pulse duration), using time-resolved polarization-sensitive optical microscopy [1]. The sample surface is excited by an intense s -polarized pump laser pulse at 800 nm (angle of incidence 45 ° ) and probed by a weak time-delayed p -polarized probe laser pulse at 400 nm (normal incidence). Snapshots of the laser-excited surface are recorded by a digital CCD-camera. Further details of the technique can be found in [1].