Raman Research Institute

A detailed time-resolved anal. of laser-produced plasmas (LPPs) is essential for understanding the effects of ambient gas on plasma characteristics.In this work, a nanosecond pulsed laser (1064 nm, 7 ns) generates LPPs from a tungsten (W) target, which is comprehensively analyzed using optical emission spectroscopy, laser plasma interferometry, shadowgraphy, and imaging.Measurements reveal that varying the ambient pressure in the 1.33 x 10³ Pa - 5.33 x 10⁴ Pa range significantly affects the plasma temperature, number d. and plume morphol.Spectral anal. reveals a strong correlation between number densities obtained from Stark broadening measurements of the H-alpha and W I lines.The interferometric method enables the study of plasma plume morphol. and retrieval of number densities even in the presence of strong continuum emission.D. maps obtained from interferometry show inhomogeneities.Shadowgraphy images show the expansion of shockwaves at different pressures, and they also reveal that the transition of plasma from non-collective to collective behavior occurs around 1 x 10⁴ Pa.Despite inhomogeneities, plasma remains in Local Thermodn. Equilibrium during the observed time window of up to 1 μs.Due to well-established Stark parameters and strong linear correlation with the W I line, the H-alpha line provides a more straightforward estimation of number densities in tungsten LPPs.

Understanding the morphol. and mech. changes in cells are important for diagnostic and treatment methods in various diseases.In sickle cell disease (SCD), the mutated Hb (HbS) aggregates inside the red blood cells (RBCs), making them rigid and, in extreme cases, sickle-shaped, resulting in anemia, episodes of pain, and multiple organ damage.Existing techniques are too costly and insensitive since the effect of the HbS gene (heterozygous and homozygous) is variable both in prevalence and clin. manifestations.In this work, we present a label-free, cost-effective, high-throughput electro-fluidic technique to study changes in the mech. and morphol. characteristics of RBCs.We validate our device by quant. comparing the mech. properties of RBCs as a function of stiffness-altering drug (Latrunculin-A) with measurements using AFM.We demonstrate the on-site application of our system by screening SCD patients based on their RBC stiffness changes.The signatures of patient-specific heterogeneity in the RBC mech. properties may help in monitoring clin. variability and identification of high-risk patients along with targeted therapies.The versatility of our measurements opens the whole cell stiffness as a preliminary screening biomarker in other haematol. conditions, tumor cell identification, in veterinary sciences as well as in evaluating hydrogel technologies.

Highly birefringent liquid crystals have grabbed ample attention because of their potential applications as an active medium for devices in visible, IR and other spectral regions.Here, we have attempted to study the effect of the size and concentration of CdS nanowires on a nematic liquid crystal.Anisotropy in liquid crystals is one of those distinguishing traits that gain their superiority over other materials.We hereby have analyzed how optical and dielec. anisotropy respond to variations in the size and concentration of the dopant.The study is of significant scientific value because there is very little literature available on how dopant size can alter liquid crystalline properties and also introduces a method to tune the properties of pure liquid crystals (LCs) by varying the size and concentration of the dopant.The study explains how the size of the nanowires changes the analyzed parameters and up to what extent.The obtained results yield a significant increase in both optical and dielec. anisotropy by doping CdS nanowires making them an excellent choice for dopant selection.CdS-doped nematic LC mixtures have proved to be highly birefringent and possess a high pos. dielec. anisotropy as well.Such a compound can be of great application in device fabrications such as laser beam steerers, electronic lenses, attenuators and light shutters, etc.