Articles written in Pramana – Journal of Physics
Volume 71 Issue 5 November 2008 pp 971-977 Small Angle Neutron Scattering
Small angle neutron scattering (SANS) has been utilized to study the morphology of the multi-walled carbon nanotubes prepared by chemical vapour deposition of acetylene. The effects of various synthesis parameters like temperature, catalyst concentration and catalyst support on the size distribution of the nanotubes are investigated. Distribution of nanotube radii in two length scales has been observed. The number density of the smaller diameter tubes was found more in number compared to the bigger one for all the cases studied. No prominent scaling of the structure factor was observed for the different synthesis conditions.
Volume 75 Issue 5 November 2010 pp 757-758
Volume 75 Issue 5 November 2010 pp 947-952 Conributed Papers
A time-dependent, two-dimensional (in space) rate equation model of a transversely-pumped pulsed dye laser oscillator, which incorporates transverse pump intensity variation in the presence of intracavity dye laser radiation, is proposed to under-stand and predict its temporal behaviour. The model yields output pulses which agree well with experimental results using rhodamine 6G and kiton red dyes. The shape, amplitude and temporal position of the simulated pulse within the pump pulse vary dramatically across the tuning range of each dye depending on the relative gain and loss values.
Volume 75 Issue 5 November 2010 pp 975-983 Conributed Papers
Photonic crystals fabricated from the colloidal spheres of polymethyl methacrylate (PMMA) using the inward-growing self-assembly technique were subse-quently in-filled with zinc oxide (ZnO) prepared by the sol–gel process. The polymer template was removed by heat treatment and chemical method to get ZnO-inverse photonic crystal. The structural quality of the inverse photonic crystal obtained by the chemical method was found to be superior to that obtained by heat treatment. The ZnO-inverse photonic crystal obtained by the chemical method was further treated at an elevated temperature to ensure the crystalline nature of ZnO. Laser-induced emission tudies on ZnO-inverse photonic crystals were carried out at an excitation wavelength of 325 nm. The emission spectra showing UV and visible bands at collection angle of 45° from the direction of excitation helped to establish the role of crystalline ZnO.
Volume 75 Issue 5 November 2010 pp 985-989 Conributed Papers
Narrow-band laser performance of alcohol solutions of pyrromethene 567 (PM567) and rhodamine 6G (RH6G) dye was investigated using a home-made GIG- configured dye laser, excited by the second-harmonic radiation (at 532 nm) of a pulsed Nd:YAG laser. Higher laser efficiency was observed with PM567 dye ($\sim 23%$ peak) in comparison to the commonly used RH6G dye (16.5%), in spite of much lower fluorescence quantum efficiency of the PM567 (0.83)
Volume 75 Issue 5 November 2010 pp 991-998 Conributed Papers
Many aspects of photophysical, photostability and laser properties of kiton red S dye remain unresolved, particularly for pumping with 578 nm radiation of CVL and 532 nm output of Nd:YAG lasers, and these are studied using different alcohol- and water-based binary solvents. Our results show that methanol is better suited for low and high-repetition-rate KRS dye lasers because of its superior laser efficiency, photostability as well as photothermal properties.
Volume 75 Issue 6 December 2010 pp 757-758
Volume 82 Issue 1 January 2014 pp 1-2
Volume 82 Issue 2 February 2014 pp 1-2
Volume 82 Issue 2 February 2014 pp 445-449 Contributed Papers
AMichelson interferometer-based technique has been used to measure the deformation of dielectric-coated mirror, caused by an incident repetitive pulsed laser beam with high average power. Minimum measurable deformation of 17 nm is reported.
Volume 82 Issue 6 June 2014 pp 1119-1119 Erratum