title: Non-degenerate fs pump-probe study on InGaN with multi-wavelength second-harmonic generation.
abstract: Non-degenerate fs pump-probe experiments in the UV-visible range for ultrafast carrier dynamics study of InGaN with adjustable pump and probe photon energies are implemented with simultaneously multiwavelength second-harmonic generation (SHG) of a 10 fs Ti:sapphire laser. The multi-wavelength SHG is realized with two beta-barium borate crystals of different cutting angles. The full-widths at half-maximum of the SHG pulses are around 150 fs, which are obtained from the cross-correlation measurement with a reverse-biased 280-nm light-emitting diode as the twophoton absorption photo-detector. Such pulses are used to perform nondegenerate pump-probe experiments on an InGaN thin film, in which indium-rich nano-clusters and compositional fluctuations have been identified. Relaxation of carriers from the pump level to the probe one through the scattering-induced local thermalization (<1 ps) and then the carrier-transport-dominating global thermalization (in several ps) processes is observed.
authors.forename: Hsiang-Chen
authors.initials: HC
authors.lastname: Wang
authors.forename: Yen-Cheng
authors.initials: YC
authors.lastname: Lu
authors.forename: Cheng-Yen
authors.initials: CY
authors.lastname: Chen
authors.forename: Chun-Yung
authors.initials: CY
authors.lastname: Chi
authors.forename: Shu-Cheng
authors.initials: SC
authors.lastname: Chin
authors.forename: C C
authors.initials: CC
authors.lastname: Yang