· The research was about developing spectral engineering technique for tailoring the output wavelength response of all-fiber interferometers through usage of standard communication grade single-mode silica fibers and interferometers. The post fabrication spectral manipulation in the proposed method requires that interferometer/filter (to be tuned) should be connected inside or outside of the FLM configuration with PCs incorporated inside the fiber loop. By changing the orientations and retardances, introduced by the PCs, in the clockwise and counter clockwise moving light beam inside the loop of FLM topology, it is possible to maneuver the spectrum of the filter/interferometer within some limitations. As an application, the ASE spectrum of the EDF has been experimentally flattened over a range of 35 nm with in an accuracy of ± 0.26 dB. The method is all-fiber, low loss and polarization independent.
· We have synthesized Au-Ag nanoparticles. The TEM image of the Au-Ag nanoparticles sample gives the confirmation of core-shell structure. The average particle size of Au-Ag core-shell is 10nm. We have characterized the sample by UV-VIS absorbance and Z-Scan technique. Under CW 532nm excitation, Z-scan measurements showed that the Au-Ag nanoparticles exhibited large thermal induced refractive index n2 .Optical limiting behavior of the Au-Ag nanoparticles has been observed
· A fiber taper station has been designed and developed for heating and elongating the fibers. The indigenously developed rig consisted of microcontroller controlled stepper motor driven elongation unit (with minimum speed of 5 micron/s), and a high temperature oxy-butane multi- nozzle torch mounted on 3-D linear translation stage. The rig was employed for tuning the MZI spectrum by stretching its arms in a controlled way and also for fabrication of bi-conical taper cascaded MMZI configuration. It has been observed that the spectrum obtained from the MMZI is more stable than that of all-fiber single-stage MZI.Further, the temperature and direct current sensing capabilities of the MMZI configurations has been investigated. The effect of change in temperature/current is displayed as shift in the output spectrum of MMZI, recorded on an optical spectrum analyzer.
- During my first post-doc at Chonbuk national university, South Korea I had an experience in the field of optical meteorology, especially interferometry-based imaging polarimetry and snapshot dynamic ellipsometry. We built perpendicular polarization-based Michelson interferometer in the spectral and spatial domain to find the ellipsometry parameters of the samples. In spatial as well as in spectral domain, the phase information can be extracted from interference fringes through one-dimensional fast Fourier transform (1D-FFT) as well two-dimensional Fourier transform (2D-FFT) using Matlab.
- During my second post PhD experience, we have build-up a Solid cell-based photo-acoustic experimental set up using 10 Hz, 9 ns pulsed laser to study absorption phenomena of RDX, HMX and TNT with PEDOT. Also, we have studied the interaction of PEDOT and RDX, HMX and TNT using Raman spectroscopy. These results were submitted in the Journal of Optics and Laser Technology. Also, I have developed an off-axis terahertz digital holography (THz-DH) imaging system using an IMPATT diode (0.1 THz) and Ne-This Camera.
- My current research work is focused on the development of an optical system for the vibration measurement to detect buried objects. Combining expertise in laser vibration sensing, acoustics and soil physics, our group head, developed advanced methods for detection of buried objects.( https://www.sciencedaily.com/releases/2019/09/190913191445.htm).