Due to the nature of interference phenomenon, optical interferometry allows for very precise measurements to be achieved. Recent discoveries extended the purpose and precision of interferometry and made it more practical and applicable. It was also revolutionized by intensive usage of photodetectors and digital signal processing electronics. Both, specular and speckle interference were used to investigate displacements, vibrations and wavefronts

We present a practical numerical method for processing the fringes obtained when two waves, with a quadratic phase difference function, interfere. This kind of fringe includes straight equispaced fringes and Newton’s rings as particular cases. The numerical method we present is based on the discrete Fresnel
Fourier transform of the data and has the same precision as least square fitting
LSF. Compared to the LSF method, this new method is better,

In this paper, a small scale laboratory strainmeter for measuring relative strains is presented. The instrument is a high resolution homodyne interferometer with polarizing optics and special designed electronics for analyzing the output signal of the interferometer. Resolution of the order of λ/8 is obtained in the first instance, with the possibility of improvement by electronic means. Measurement range could vary from microns in the case of earth

We discuss an experiment for detecting small deformations by speckle interferometry. Vibration modes of an aluminium plate are observed by digital speckle pattern interferometry (DSPI). A Mach-Zender interferometer arrangement is used and the speckle interferograms are recorded with a CCD camera and processed on a computer. These fringes depend on the path differences due to the vibration of the aluminium plate from its original state. Vibration

The article present an ultralow frequency passive vibration isolation device as part of the preisolation stage for the Australian International Gravitational Observatory ~AIGO!. This isolator is based on the Roberts linkage and simulates a very long radius conical pendulum to provide two-dimensional isolation. It is designed as the second horizontal isolation component of the preisolator and it will support the remaining four isolation stages of

In this paper, we investigate the use of radiation pressure force as test mass actuation for laser interferometer gravitational wave detectors. It is shown that it is viable to provide radiation pressure control on test masses for frequencies above ∼0.2 Hz in high performance vibration isolation systems. A very low mass, low frequency resonator has been used to verify that radiation pressure force is not corrupted by other forces such as due to