2015/03/31 by Eiichi Matsubara, Takeshi Mochizuki, Masaya Nagai +2
Engineering · Physics and Astronomy · #Absorption (acoustics) #Bismuth #Bismuth ferrite #Ferrite (magnet) #Multiferroics #Nonlinear Optical Materials Studies #Nonlinear Photonic Systems #Nonlinear optical #Photorefractive and Nonlinear Optics #Single crystal #Ultrashort pulse #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.7567/jjap.54.092201
6 pages
arxiv created 2015/03/31 · openalex publication_date 2015/08/05 · arxiv updated 2015/09/02 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We studied the ultrafast third-order optical nonlinearity in a single crystal of multiferroic bismuth ferrite (BiFeO 3 ) in the near-infrared range of 0.5–1.0 eV, where the material is fundamentally transparent, at room temperature. With pump pulses at 1.55 eV, which is off-resonant to the strong inter-band charge transfer (CT) transition, we observed instantaneous transient absorption with a pencil-like temporal profile originating from the two-photon CT transition from the oxygen 2p to the iron 3d levels. In contrast, under pumping with 3.10 eV photons, the pencil-like absorption change was not observed but decay profiles showed longer time constants. Although the two-photon absorption coefficient estimated to be 1.5 cm/GW is 10 (100) times smaller than that of two (one)-dimensional cuprates, it is larger than those of common semiconductors such as ZnSe at the optical communication wavelength.