P. Hariharan

Bio: P. Hariharan is an academic researcher from University of Sydney. The author has contributed to research in topics: Interferometry & Holography. The author has an hindex of 28, co-authored 88 publications receiving 3637 citations. Previous affiliations of P. Hariharan include Commonwealth Scientific and Industrial Research Organisation.

Digital phase-shifting interferometry: a simple error-compensating phase calculation algorithm.

Abstract: La difference de phase entre les 2 faisceaux interferant varie de maniere connue et on fait des mesures de la distribution d'intensite a travers la pupille correspondant a au moins 3 dephasages differents

Optical holography : principles, techniques, and applications

Abstract: This book presents a self-contained treatment of the principles, techniques and applications of optical holography, with particular emphasis on recent developments. The first part deals with the theory of holographic imaging, the characteristics of the reconstructed image and the different types of holograms. The next section covers the practical aspects of holography - optical systems, light sources and recording media - as well as the production of holograms for display, colour holography and computer-generated holograms. Finally, there is a detailed description of the most important applications of holography. These include particle-size analysis, high-resolution imaging, holographic optical elements and information storage and processing, as well as holographic interferometry and its use in stress analysis, vibration studies and contouring.

Basics of Interferometry

Abstract: Chapter 1: Introduction Chapter 2: Interference: A Primer Chapter 3: Two-Beam Interferometers Chapter 4: Source-Size and Spectral Effects Chapter 5: Multiple-Beam Interference Chapter 6: The Laser as a Light Source Chapter 7: Photodetectors Chapter 8: Measurements of Length Chapter 9: Optical Testing Chapter 10: Digital Techniques Chapter 11: Macro- and Micro-Interferometry Chapter 12: White-Light Interference Microscopy Chapter 13: Holographic and Speckle Interferometry Chapter 14: Interferometric Sensors Chapter 15: Interference Spectroscopy Chapter 16: Fourier-Transform Spectroscopy Chapter 17: Interference with Single Photons Chapter 18: Building an Interferometer Appendix A: Monochromatic Light Waves Appendix B: Phase Shifts on Reflections Appendix C: Diffraction Appendix D: Polarized Light Appendix E: The Pancharatnam Phase Appendix F: The Twyman-Green Interferometer: Initial Adjustment Appendix G: The Mach-Zehnder Interferometer: Initial Adjustment

Basics of Holography

Abstract: Basics of Holography is a general introduction to the subject written by a leading worker in the field It begins with the theory of holographic imaging, the characteristics of the reconstructed image, and the various types of holograms Practical aspects of holography are then described, including light sources, the characteristics of recording media and recording materials, as well as methods for producing different types of holograms and computer-generated holograms Finally, important applications of holography are discussed, such as high-resolution imaging, holographic optical elements, information processing, and holographic interferometry The book includes comprehensive reference sections and appendices summarizing some useful mathematical results Numerical problems with their solutions are provided at the ends of chapters This is an invaluable resource for advanced undergraduate and graduate students as well as researchers in science and engineering who would like to learn more about holography and its applications in science and industry

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

Abstract: A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

V Phase-Measurement Interferometry Techniques

Abstract: Publisher Summary This chapter describes the phase-measurement interferometry techniques. For all techniques, a temporal phase modulation is introduced to perform the measurement. By measuring the interferogram intensity as the phase is shifted, the phase of the wavefront can be determined with the aid of electronics or a computer. Phase modulation in an interferometer can be induced by moving a mirror, tilting a glass plate, moving a grating, rotating a half-wave plate or analyzer, using an acousto-optic or electro-optic modulator, or using a Zeeman laser. Phase-measurement techniques using analytical means to determine phase all have some common denominators. There are different equations for calculating the phase of a wavefront from interference fringe intensity measurements. The precision of a phase-measuring interferometer system can be determined by taking two measurements, subtracting them, and looking at the root-meansquare of the difference wavefront. The chapter discusses the simulation results. The elimination of the errors that reduce the measurement accuracy depends on the type of measurement being performed. Phase-measurement interferometry (PMI) can be applied to any two-beam interferometer, including holographic interferometers. Applications can be divided into: surface figure, surface roughness, and metrology.

Digital wavefront measuring interferometer for testing optical surfaces and lenses

Abstract: A self-scanned 1024 element photodiode array and minicomputer are used to measure the phase (wavefront) in the interference pattern of an interferometer to lambda/100. The photodiode array samples intensities over a 32 x 32 matrix in the interference pattern as the length of the reference arm is varied piezoelectrically. Using these data the minicomputer synchronously detects the phase at each of the 1024 points by a Fourier series method and displays the wavefront in contour and perspective plot on a storage oscilloscope in less than 1 min (Bruning et al. Paper WE16, OSA Annual Meeting, Oct. 1972). The array of intensities is sampled and averaged many times in a random fashion so that the effects of air turbulence, vibrations, and thermal drifts are minimized. Very significant is the fact that wavefront errors in the interferometer are easily determined and may be automatically subtracted from current or subsequent wavefrots. Various programs supporting the measurement system include software for determining the aperture boundary, sum and difference of wavefronts, removal or insertion of tilt and focus errors, and routines for spatial manipulation of wavefronts. FFT programs transform wavefront data into point spread function and modulus and phase of the optical transfer function of lenses. Display programs plot these functions in contour and perspective. The system has been designed to optimize the collection of data to give higher than usual accuracy in measuring the individual elements and final performance of assembled diffraction limited optical systems, and furthermore, the short loop time of a few minutes makes the system an attractive alternative to constraints imposed by test glasses in the optical shop.

Analysis and applications of optical diffraction by gratings

Abstract: Diffraction characteristics of general dielectric planar (slab) gratings and surface-relief (corrugated) gratings are reviewed. Applications to laser-beam deflection, guidance, modulation, coupling, filtering, wavefront reconstruction, and distributed feedback in the fields of acoustooptics, integrated optics, holography, and spectral analysis are discussed. An exact formulation of the grating diffraction problem without approximations (rigorous coupled-wave theory developed by the authors) is presented. The method of solution is in terms of state variables and this is presented in detail. Then, using a series of fundamental assumptions, this rigorous theory is shown to reduce to the various existing approximate theories in the appropriate limits. The effects of these fundamental assumptions in the approximate theories are quantified and discussed.

Digital phase-shifting interferometry: a simple error-compensating phase calculation algorithm.

Abstract: La difference de phase entre les 2 faisceaux interferant varie de maniere connue et on fait des mesures de la distribution d'intensite a travers la pupille correspondant a au moins 3 dephasages differents