Abstract
Abstract
This work presents the development of an ultrahigh-speed
digital holography instrument that can perform volumetric
measurements at a rate of up to 100 million frames per second. The
system is based on an Ultra 8 camera that uses a single custom-built
image intensifier with a segmented photocathode that can gate eight
different imaging regions down to 10 ns. An in-line interferometric
scheme is used to capture the deformation of a water drop as it is
photoablated from irradiation by a 1064 nm wavelength pulsed laser
beam. After a digital holographic video is captured, wavefront
reconstruction is used to focus on discrete depth planes enabling
the user to observe different 3-dimensional features of the drop as
the field-of-view is scanned plane-by-plane. The reconstructions are
detwinned and corrected for parallax and alignment error before a
final image at any given depth is produced. We provide one-to-one
comparisons between conventional focused imaging and digital
holography to demonstrate the 3-dimensional visualization
capabilities of the instrument with particular regard to dynamic
events occurring at nanosecond time intervals for future
applications to hypersonic flows and other short and ultrashort
duration events.
Subject
Mathematical Physics,Instrumentation