title: Femtosecond imaging of nonlinear acoustics in gold.
abstract: We have developed a high-sensitivity, low-noise femtosecond imaging technique based on pump-probe time-resolved measurements with a standard CCD camera. The approach used in the experiment is based on lock-in acquisitions of images generated by a femtosecond laser probe synchronized to modulation of a femtosecond laser pump at the same rate. This technique allows time-resolved imaging of laser-excited phenomena with femtosecond time resolution. We illustrate the technique by time-resolved imaging of the nonlinear reshaping of a laser-excited picosecond acoustic pulse after propagation through a thin gold layer. Image analysis reveals the direct 2D visualization of the nonlinear acoustic propagation of the picosecond acoustic pulse. Many ultrafast pump-probe investigations can profit from this technique because of the wealth of information it provides over a typical single diode and lock-in amplifier setup, for example it can be used to image ultrasonic echoes in biological samples.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pezeril
authors.forename: Christoph
authors.initials: C
authors.lastname: Klieber
authors.forename: Viktor
authors.initials: V
authors.lastname: Shalagatskyi
authors.forename: Gwenaelle
authors.initials: G
authors.lastname: Vaudel
authors.forename: Vasily
authors.initials: V
authors.lastname: Temnov
authors.forename: Oliver G
authors.initials: OG
authors.lastname: Schmidt
authors.forename: Denys
authors.initials: D
authors.lastname: Makarov
mesh_terms: D006046:Gold / Q000737:chemistry*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D017711:Nonlinear Dynamics; D013997:Time Factors
chemical_list: D006046:Gold