A large-field laser holographic focusing schlieren system for high-spe
ed three-dimensional now visualization has been built and evaluated. T
his system is based on a recently improved large-field focusing schlie
ren technique and is combined with laser holography methods to obtain
a three-dimensional recording. A coordinated experimental and computat
ional study of supersonic flows over a two-dimensional wedge and a sph
ere was conducted to evaluate the capabilities and limitations of the
system. Also, the concept of a spread function is introduced to descri
be the dependence of the recorded intensity change on the refractive i
ndex for focusing schlieren systems. The ability of the system to focu
s on planes normal to its optical axis is demonstrated. However, the s
harpness of focus of the present system was found to be limited.