[Problem] To provide a low-cost, high-precision three-dimensional shape measuring device using vibration-resistant phase shift digital holography.

[Solution] A three-dimensional shape measuring device, wherein an object-light optical system allows object light to be incident on a polarization element for detecting relative phase differences in a first circularly polarized light state, a reference-light optical system allows a reference light to be incident on a polarization element for detecting relative phase differences in a second circularly polarized light state in the direction opposite from the first circularly polarized light, and the polarization element for detecting relative phase differences transmits a component of the object light, which is the first circularly polarized light, in the polarization direction of the polarization element for detecting relative phase differences, and a component of the reference light, which is the second circularly polarized light, in the polarization direction of the polarization element for detecting relative phase differences. The polarization direction of the polarization element for detecting relative phase differences is rotated to thereby vary the relative phase difference between the object light and the reference light transmitted through the polarization element for detecting relative phase differences and to acquire a plurality of hologram images having different relative phase differences.

Eine Vorrichtung (1) zum Erfassen einer 3D-Struktur eines Objekt umfasst einen ersten Laser-Emitter (2a), der Laserstrahlung mit einer ersten Wellenlänge erzeugt, einen zweiten Laser-Emitter (2b), der Laserstrahlung mit einer zweiten Wellenlänge erzeugt, wobei sich die erste Wellenlänge von der zweiten Wellenlänge unterscheidet, optische Einrichtungen (4, 9, 10, 13, 14), von denen wenigstens eine ein Strahlteiler (4) ist, der die Laserstrahlung der Laser-Emitter (2, 2a, 2b) jeweils in eine Referenzstrahlung (5) und einen Beleuchtungsstrahlung (6) aufteilt, wobei die Beleuchtungsstrahlung (5) auf das zu vermessende Objekt (15) trifft, von dem Objekt (15) als Objektstrahlung (21) reflektiert wird und mit der Referenzstrahlung (5) interferiert und einen Detektor (12), der die daraus entstehenden Interferenzmuster aufnimmt.

Die Laser-Emitter (2, 2a, 2b) sind derart angeordnet, dass die Beleuchtungsstrahlung (6) des ersten Laser-Emitters (2a) und die Beleuchtungsstrahlung (6) des zweiten Laser-Emitters (2b) mit unterschiedlichen Einfallswinkeln auf das Objekt (15) treffen.

Die Vorrichtung (1) umfasst weiter eine Messeinrichtung (27), welche die beiden Wellenlängen der Laserstrahlung der Laser-Emitter (2, 2a, 2b) misst und die Aufnahme der Interferenzmuster beeinflusst.

In the interferometric system, the image plane 3.3 of an imaging setup 3.1 of an object branch is imaged by means of an output imaging setup 4 via a transmission system 6.1 of reflectors to the output plane 7 and simultaneously in the image plane 3.4 of an imaging setup 3.2 of a reference branch is a reflection type diffraction grating 5 located, which is imaged by the output imaging setup 4 via a transmission system 6.2 of reflectors also to the output plane 7 of the interferometer where an achromatic off-axis hologram is formed by the interference of waves coming from both the object branch and the reference branch and where a detector is located. The transmission systems of reflectors 6.1 and 6.2 are adjusted in such a way that axes of both branches coincide at an entrance to the output plane 7 and they are parallel with a normal line of the output plane 7, and an axial beam, diffracted by the reflection type diffraction grating 5 at an angle α, enters into the output plane 7 at an angle β, and the relation between angle β and α is sin(β) = sin(α)/m, where m is a magnification of the output imaging setup 4.

The system enables the achievement of a holographic imaging of an object by means of low-coherence waves, e.g. white light from an extended light source. Incoherent waves allow the imaging of objects immersed in scattering media. The imaging is carried out in real time. It is possible to use a single digitally recorded hologram of a part of the observed object and numerically reconstruct the object wave, it means its intensity and phase. Intensity imaging is depth discriminated; therefore it represents a cross-section through the observed sample. The cross-section thickness depends on a degree of coherence of the used waves and, if light microscopy is considered, it can be narrower than an optical cross-section obtained by a confocal microscope. The phase image corresponds to the difference of times of propagation through the object and the reference branches caused by the observed sample, it is quantitative and may be used for measuring a depth of reflective samples with accuracy in orders of thousandths of a wavelength, or, for example, in case of transmitted-light microscopic imaging, it can be used to weigh cells or to analyze an intracellular mass movement.

An apparatus and method are disclosed for providing holographic matched filters for application in all-optical holographic processing of ultrahigh-speed optical data. A scaled spatial image of temporal-domain data is provided by a spatial light modulator (SLM). The scaled image of the SLM is read out with a single-mode diode laser and transformed into a wavelength spectrum by a Fourier transform lens. The interference fringe patterns between the spectrum of the scaled spatial data pattern and the reference pattern beam are recorded by a holographic recording medium. Alternatively, the scaled spatial image of the temporal data is fixed in an aperture mask. An apparatus and method are also disclosed for decoding high-speed optical signal packet headers using holographic matched filters.