Observation of the Fresnel and Arago laws using the Mach-Zehnder interferometer

An experimental study is conducted to determine the effect of polarization on the interference of light waves. By using the temporal coherence property of light in a Mach-Zehnder interferometer, we verified the four important Fresnel and Arago laws for linearly polarized and circularly polarized light. This experiment provides a simple method for undergraduates to study the phenomena of interference and polarization. (C) 2008 American Association of Physics Teachers

Spatial Light Modulators and Their Applications in Polarization Holography

Liquid crystal spatial light modulators (LC-SLMs) have gained substantial interest of the research fraternity due to their remarkable light modulation characteristics in modern imaging applications. Replacing the conventional optical elements from the SLM-based computer-generated holograms (CGHs) is a trending approach in modern digital holographic applications due to the optimized phase shift depending on the phase modulation features of SLMs. Apparently; SLMs serve a crucial role in the experimental implementation of digital holographic techniques. However, the resolution of the CGHs are sometimes limited by the structural discrepancies (fill factor, spatial anomalies, refresh rate, etc.) of SLM. Therefore, it is recommended to calibrate the modulation characteristics of SLMs prior to their implementation for imaging applications. This chapter provides comprehensive literature (review) of the LC-SLMs along with their major calibration methods. In addition, recent interesting applications of LC-SLMs have been discussed thoroughly within the framework of polarization holography

Ghost diffraction: A spatial statistical approach

We report the reconstruction of a transparency image in Ghost diffraction scheme using a statistical optics approach. This is implemented by using a static diffuser rather than a pseudo thermal light source with a rotating diffuser. The experimental implementation makes use of spatial ergodicity and spatial stationarity for spatially distributed random fields. A strategy to realize the Ghost diffraction scheme through spatial intensity correlation with a phase retrieval algorithm permits reconstruction of the transparency

Modifications to the Hadronic Regge Trajectories

The effect of quark mass on the Regge trajectory is analysed. Modifications in the equations of Regge trajectories are shown for mesonic as well as baryonic systems. For mesonic systems, the Regge trajectories get modified, but still remain linear. Contrary to the mesonic case, the Regge trajectories for baryonic systems indicate non-linearity. It is shown that in low mass and angular momentum region two hadrons with different quark compositions can have same mass and angular momentum.Comment: 20 pages, 13 figures, Published in MPLA, corrected versio

Effects of demand-side financing on utilisation, experiences and outcomes of maternity care in low- and middle-income countries: a systematic review.

Demand-side financing, where funds for specific services are channelled through, or to, prospective users, is now employed in health and education sectors in many low- and middle-income countries. This systematic review aimed to critically examine the evidence on application of this approach to promote maternal health in these settings. Five modes were considered: unconditional cash transfers, conditional cash transfers, short-term payments to offset costs of accessing maternity services, vouchers for maternity services, and vouchers for merit goods. We sought to assess the effects of these interventions on utilisation of maternity services and on maternal health outcomes and infant health, the situation of underprivileged women and the healthcare system

Combined Jones–Stokes Polarimetry and Its Decomposition into Associated Anisotropic Characteristics of Spatial Light Modulator

Jones–Stokes polarimetry is a robust in vitro polarimetric technique that can be used to investigate the anisotropic properties of a birefringent medium. The study of spatially resolved Jones matrix components of an object is a heuristic approach to extract its phase and polarization information. However, direct interpretation of Jones matrix elements and their decomposition into associated anisotropic properties of a sample is still a challenging research problem that needs to be investigated. In this paper, we experimentally demonstrate combined Jones–Stokes polarimetry to investigate the amplitude, phase, and polarization modulation characteristics of a twisted nematic liquid crystal spatial light modulator (TNLC-SLM). The anisotropic response of the SLM is calibrated for its entire grayscale range. We determine the inevitable anisotropic properties viz., diattenuation, retardance, isotropic absorption, birefringence, and dichroism, which are retrieved from the measured Jones matrices of the SLM using Jones polar decomposition and a novel algebraic approach for Jones matrix decomposition. The results of this study provide a complete polarimetric calibration of the SLM within the framework of its anisotropic characteristics

Combined Jones–Stokes Polarimetry and Its Decomposition into Associated Anisotropic Characteristics of Spatial Light Modulator

Jones–Stokes polarimetry is a robust in vitro polarimetric technique that can be used to investigate the anisotropic properties of a birefringent medium. The study of spatially resolved Jones matrix components of an object is a heuristic approach to extract its phase and polarization information. However, direct interpretation of Jones matrix elements and their decomposition into associated anisotropic properties of a sample is still a challenging research problem that needs to be investigated. In this paper, we experimentally demonstrate combined Jones–Stokes polarimetry to investigate the amplitude, phase, and polarization modulation characteristics of a twisted nematic liquid crystal spatial light modulator (TNLC-SLM). The anisotropic response of the SLM is calibrated for its entire grayscale range. We determine the inevitable anisotropic properties viz., diattenuation, retardance, isotropic absorption, birefringence, and dichroism, which are retrieved from the measured Jones matrices of the SLM using Jones polar decomposition and a novel algebraic approach for Jones matrix decomposition. The results of this study provide a complete polarimetric calibration of the SLM within the framework of its anisotropic characteristics

The influence of source and object characteristics on coincidence imaging

A classical coincidence imaging or ghost imaging experiment is carried out in a two-photon counting regime using a pseudo-thermal incoherent light source. The effect of the transverse size and transverse coherence width of the source on the visibility and the resolution of the reconstructed ghost image is studied. It is observed that by increasing the transverse size of the source, the resolution (quality) of the reconstructed image improves, while the visibility reduces. On the other hand, as the coherence width of the source increases, the visibility of the image increases but the resolution becomes poor. The effect of object characteristics on the visibility of the ghost image is also studied and it is found that by increasing the number of transparent features and the surface size of the object, the visibility of the image decreases. These experimental results validate the theoretical results published so far