Temporal evolution of photo-induced thermal strain in InSb probed by ultra-short laser produced Cu Kα x-rays

Abstract

Development and characterization of a wire target based kHz rep rate Cu Kα x-ray source using a Ti:sapphire laser system and its use in time resolved x-ray diffraction (TXRD) of the InSb (111) sample are presented. The observed Kα x-ray photon flux is ∼3.2 × 109 photons sr−1 s−1 at a laser intensity of ∼3.5 × 1016 W cm−2. TXRD signal from the InSb (111) crystal pumped by an ultrashort Ti:sapphire laser pulse (fluence ∼ 13 mJ cm−2) shows a lattice expansion due to heating on a multipicosecond time scale. The crystal gradually cools down and recovers at ∼1.5 ns after the laser excitation. The observed strain variation in the crystal matches well with the simulated results. The study of full recovery of the sample will be helpful for the development of InSb based devices.