Research Interests

The field of optics blended with modern material fabrication technologies has given rise to the field of Photonics.  This includes nano-photonics, quantum photonics, bio-photonics, nonlinear photonics etc. which has substantially extended the reach of optics to many other disciplines of Science and Technology. The invention of Laser by Theodore Maiman at Hughes Labs in the year 1960 followed by rapid progress in Laser Technology has provided a strong impetus to the field of Photonics. Today, Photonics is touching the human life from every possible direction and the applications range from Telecommunications to Medicine, from Military Warfare to Entertainment Industry. 

The LONP group focuses on devising high-power second harmonic generators, optical parametric generators (OPGs) and optical parametric oscillators (OPOs) which provide plausible routes to reach those spectral regions that are inaccessible to conventional laser technology via exploiting second-order nonlinear optical properties of non-centro-symmetric crystals. The group develops high-power, frequency (or wavelength) tunable sources in the mid-infrared and far-infrared spectral bands at continuous-wave (cw) or quasi-cw and ultrashort (femtosecond) time scales. Such sources are employed for trace-gas sensing and absorption spectroscopy of trace-gas molecules such as methane, formaldehyde, nitrogen, carbon-dioxide along with probing the atomic Rydberg states. They also act as potential coherent optical sources employed for optical countermeasure operations and border patrolling. In addition, the group collaboratively investigates the absorption and emission characteristics of a broad class of sub-wavelength organic and inorganic aggregates (or nanoparticles/nanoclusters) using the nonlinear optical spectroscopy through estimating the third-order nonlinear optical coefficients. In order to accomplish the objectives, the group employs a variety of techniques such as Z-scan, I-scan, four-wave mixing (FWM) and interferometry for ascertaining the third-order nonlinear optical coefficients.

The primary bottleneck in most of the optical signal processing and optical transmission circuits is ‘unwanted scattering’ which includes ‘backscattering’. ‘Topologically-protected’ modes in optics/photonics provide a potentially viable route to circumvent the undesirable impact of ‘backscattering’ of light. In this area of research, the group investigates a broad range of linear (photonic crystal based) and nonlinear optical systems for which the topological constants could be ascertained. Subsequently, the impact of perturbations and tolerance with regard to backscattering is investigated. This area of research also provides a plausible route to explore symmetry aspects of parametric (lossless) as well as non-parametric electromagnetic (optical as well as plasmonic) interactions.