Complex acoustic waveforms excited with multiple picosecond transient gratings formed using specially designed phase-only beam-shaping optics

This paper describes a method for using a pulsed laser and specialized low cost beam-shaping optics to launch complex acoustic waveforms with user-definable geometries; diffraction of a continuous wave probe laser from these waveforms reveals their temporal evolution in real time. Methods are introduced for designing and fabricating simple binary phase optics for beam-shaping that is useful for high-frequency measurements on thin films. Experiments on films of platinum on silicon demonstrate the approach.