Work History

Work History
Oct 2009 - Present

Research Associate

ACRHEM, University of Hydserabad

At present I am working on characterizing the intense, short pulse laser produced shock waves in a media. A direct consequence of this study is to understand the Equation of State (EOS) of the material under extreme condtions in a controlled laboratoy environmernt.

Education

Education
Aug 2001 - Oct 2007

Ph. D.

Tata Institute of Fundamental Research

During my Ph. D. work at Tata Institute of Fundamental Research, my basic aim has been to find out the impact of surface roughness on energetic ion emission from intense laser produced solid plasmas. In contrast to the existing conventional particle accelerators, laser produced plasma have come up with the potential of developing efficient energetic ion sources at smaller dimensions. Although it is observed that under appropriate conditions short pulse laser based accelerators can give rise to high energy charged particle beams but to use them on routine basis operation the efficiency of these methods have to be improved. One of the prime challenges in this aspect is the efficient coupling laser energy into the plasma.

                      The surface structures are known to enhance the laser energy coupling up to 90% when compared to a conventional polished target. With the recent developments in the production of nanostructures with high quality and characteristic reproducibility, they can form the basis of the efficient coupling of laser energy into the plasma on a routine basis. The work reported in my thesis presents pathways toward exploiting these surface modulations appropriately towards achieving an efficient photon and charged particle sources depending on the user requirement.

                 During my thesis work, I have designed and implemented a versatile experimental set up easily adaptable to various challenges faced in this field of research. The conventional and structured surfaces are kept side by side ensuring identical experimental conditions. The X-ray energy was measured by a calibrated NaI(Tl) detector while the ejected high energy ions were measured by a channel electron multiplier in proportional mode, exploiting conventional ion arrival time measurement technique. To estimate the spatial divergence of the laser beam, four annular Faraday cups were employed.

                The thesis work identifies the key mechanisms responsible for the enhanced laser energy coupling, namely, i) surface plasmon resonance and ii) "lightning rod" effect. It demonstrates that the surface plasmon resonance can be exploited to channelize major part of the absorbed laser energy to energetic ions emitted from the plasma. Whereas, the "lightning rod" factor, yields brighter harder X-ray sources with low energy (ion) debris.

Skills

Skills

Skills

Designing and development of a versatile multitasking experimental system for laser plasma studies with a 7 TW femtosecond laser system (THALES Lasers, ALPHA-10). The system is designed to handle experimental studies with wide range of targets from gas puffs, liquid droplets and also the conventional solid targets. The system houses a motorized stage assembly (x-y-z-θ, z being the laser propagation direction and θ is the rotation angle about y (vertical) axis) to scan the target so that at each laser pulse is incident on a fresh region of the solid target The laser is focused with an Off Axis Parabolic mirror in f/4 geometry to 10 µm. The system houses a high resolution imaging system so that the scanning of the target can be monitored and especially in a two pulse experiments, the spatial overlap of the beam can be achieved with the few micron resolution microscopic images.  Designed and development a Time of Flight mass spectrometer (TOFMS) to detect the charged particles emitted from intense laser produced plasma. The system was later evolved to a Thompson parabola mass spectrometer with a position sensitive detector (MCP coupled to a p47 phosphor screen) and the images are collected with a fast CCD camera. I have developed the image acquisition system for this instrument using LabViewTM software.  Designed and development of a space resolved integral charge measurement system to measure the divergence in ion emission from intense laser produced plasma.  Implementation of computer controlled data acquisition (DAQ) system incorporating high speed digitizers, high speed Digital Oscilloscope and GPIB controllable devices for synchronous operations the experiments using LabViewTM software.   Development of high resolution image acquisition and analyzing systems to study the spatial evolution of the filaments using LabViewTM software.  Experienced in the installation, operation and maintenance of 20 TW, 30 fs, 10 Hz repetition rate Ti: Sapphire laser (THALES Lasers, ALPHA-10) as well as 0.5 TW, 100 fs, 10 Hz repetition rate Ti:Sapphire laser.    Development of Finite Difference Time Domain (FDTD) code to study the enhancement of the local electric field in the vicinity of the nano-structures under the influence of the ultrashort intense laser pulse.  Experienced in using AUTOCADTM, SIMIONTM, LabViewTM, MATLABTM, FORTRAN77 Experienced in working with 3D PIC code PICVIC-3D developed by Dr. Kartik Patel (BARC). Experienced is using Lanex, Image plates, CR-39 and radiochromic films  Experienced in using ICCD cameras & Echelle spectrograph from time resolved imaging of laser produced plasmas