Single-shot multiwavelength shape measurements with restricted aperture

Abstract

We propose a new application of broad band lasers for digital holography. The aim is to capture the shape of objects by a single hologram using multiple wavelengths. Our approach is to separate the reference wave spectrally by a grating while the object wave remains unaffected. This leads to many lamellar holograms in one hologram. As consequence different restrictions like aperture and wavelength dependency of the reconstruction algorithm have to be taken into account. In experiments we have successfully demonstrate that lamellar holograms can be generated, reconstructed and that all necessary steps for shape measurement are accomplishable.

Dynamic wave field synthesis: enabling the generation of field distributions with a large space-bandwidth product

“…Since their invention by Dennis Gabor in 1948 and of coherent laser light in 1960, holograms have motivated innumerable inventions. Specifically in the field of modern optics these applications include microscopy [3,4], data storage [5,6], metrology [7][8][9][10], and advanced imaging [11][12][13]. Another application has been the synthesis and analysis of optical wave fields [14][15][16][17].…”

“…Now let us assume that this sampling is done in accord with the sampling theory, i.e. with spacings 9) where B i is the bandwidth of U s in the i−th direction. The total number of significant samples required to represent U s can be expressed in terms of the SBWP as follows…”