Measurement of Out-of-plane Dynamic Deformations by Digital Speckle Pattern Interferometry

In this paper, measurement of dynamic deformations in a rectangular plate fixed at one end, using digital speckle pattem interferometry (DSPI), has been prese,nted. To improve the measurement accuracy,a new filtering scheme has been developed. This scheme is based on the combination of average/ median filtering and Symlet wavelet filtering which enhances the signal-to-noise ratio in the speckleinterferogram obtained from the DSPI. Experimental results show that this filtering scheme is quite effective in improving signal-to-noise ratio of the speckle .interferogram. The measurements by DSPIand accelerometer are in good agreement. The DSPI technique can be implemented for measuring the large deformations as well

Application of Atomic Force Microscopy in Organic and Perovskite Photovoltaics

Atomic force microscopy (AFM) has become widely used technique in air, liquids, or vacuum to generate high-resolution topographic images of a surface having a nanometer-scale resolution. AFM gives the information about the morphology, phase composition etc. Photovoltaic materials have been attracting intense interest due to their performance and the morphology as well as quality of these materials affects their performance. AFM is now a day widely used technique for morphology and other electronic properties measurements at nanoscale for photovoltaic materials to understand their relation with device performance. This chapter describe the brief introduction of Kelvin probe force microscopy (KPFM) and conducting atomic force microscopy (CAFM) and their application in electrical characterization at nanoscale of organic and perovskite photovoltaic materials

Applications of Digital Holographic Interferometry in Heat Transfer Measurements from Heated Industrial Objects

Digital holographic interferometry (DHI) is used worldwide for many scientific and industrial applications. In DHI, two digital holograms; one in the reference/ambient state of the object and another in changed state of object are recorded by electronic imaging sensors (such as CCD/CMOS) as reference holograms and object holograms, respectively. Phase of object wavefronts in different states of the object is numerically reconstructed from digital holograms. The interference phase is reconstructed by subtracting the phase of reference hologram from the phase of object hologram, without performing any phase-shifting interferometry. Thus, no extra effort is needed in DHI for calculating the interference phase. Apart from direct reconstruction of interference phase from two digital holograms, the recent development, availability of recording devices at video rate, and high-performance computers make the measurements faster, reliable, robust, and even real-time. In this chapter, DHI is presented for the investigation of temperature distribution and heat transfer parameters such as natural convective heat transfer coefficient and local heat flux around the surface of industrial heated objects such as cylindrical wires and heat sinks

Surface-Enhanced Raman Scattering: Introduction and Applications

Scattering of light by molecules can be elastic, Rayleigh scattering, or inelastic, Raman scattering. In the elastic scattering, the photon’s energy and the state of the molecule after the scattering events are unchanged. Hence, Rayleigh scattered light does not contain much information on the structure of molecular states. In inelastic scattering, the frequency of monochromatic light changes upon interaction with the vibrational states, or modes, of a molecule. With the advancement in the laser sources, better and compact spectrometers, detectors, and optics Raman spectroscopy have developed as a highly sensitive technique to probe structural details of a complex molecular structure. However, the low scattering cross section (10−31) of Raman scattering has limited the applications of the conventional Raman spectroscopy. With the discovery of surface-enhanced Raman scattering (SERS) in 1973 by Martin Fleischmann, the interest of the research community in Raman spectroscopy as an analytical method has been revived. This chapter aims to familiarize the readers with the basics of Raman scattering phenomenon and SERS. This chapter will also discuss the latest developments in the SERS and its applications in various fields

Measurement of temperature profile of two-dimensional slot burner using a lau phase interferometer with linear gratings.

We have investigated the utility of a Lau phase interferometer with linear gratings and white light source to measure the temperature and temperature profile of a flame produced by a slot burner used in an atomic absorption spectrophotometer. The temperature values measured using a Lau phase interferometer and a thermocouple and multilogger are in good agreement. The effect of aspirating water through a nebulizer on the temperature profile and details of theoretical analysis and experimental investigations are also presented

Sinusoidal fringe projection system based on compact and non-mechanical scanning low-coherence Michelson interferometer for three-dimensional shape measurement

We report a sinusoidal fringe projection system based on superluminiscent diode (SLD) as a broad-band light source in conjunction with an acousto-optic tunable filter (AOTF) as frequency tuning device for three-dimensional shape measurement. The present system is based on a compact low-coherence Michelson interferometer system. The conventional interferometric system was modified in which one side of the beam splitter was coated with aluminum oxide which is used as reference mirror. With this modified version, interference fringes can easily be obtained by simply placing the external mirror in contact on the other side of beam splitter. Sinusoidal fringes with multiple spatial-carrier frequency can be generated in real-time using the present system by means of changing the radio-frequency signal to AOTF electronically without mechanically moving any component in the system. The present system was tested by projecting the sinusoidal fringes on a step-like object and 3D shape of the object was reconstructed using Fourier transform fringe analysis technique. The main advantages of the proposed system are completely non-mechanical scanning, easy to align, high stability because of its nearly common-path geometry and compactness