title: Amplitude and phase analysis in digital dynamic holography.
abstract: Lensless in-line digital holographic interferometry has the potential for vibration analysis of objects smaller than 5 mm in diameter. This is particularly useful for dynamic characterization of microelectromechanical systems devices. To achieve this, there is a need to magnify the object wave, which is done using a diverging beam. It is observed that an increase in the object-to-CCD distance increases the sensitivity of the amplitude-modulated time-average fringes. At the same time the effect on phase information that represents the mean static deformation of a vibrating object is studied. It is also observed that a reduction in the object-to-CCD distance increases the phase sensitivity as evidenced by the double-exposure time-average fringes. The experimental observation and a theoretical explanation for this contradictory phenomenon are presented.
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798.
authors.forename: Anand
authors.initials: A
authors.lastname: Asundi
authors.forename: Vijay Raj
authors.initials: VR
authors.lastname: Singh