Amplitude and phase analysis in digital dynamic holography

• Main Authors: Anand, Asundi, Singh, Vijay Raj
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Article
• Language: English
• Published: 2011
• Subjects: DRNTU::Science::Physics::Optics and light
• Online Access: https://hdl.handle.net/10356/94146; http://hdl.handle.net/10220/7026
• Institution: Nanyang Technological University

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.