Sanchita Ghosh received her MS in Electronics and Communication Engineering (ECE).  Her research work was supervised by Dr. Azeemuddin Syed. Here’s a summary of Sanchita Ghosh’s  MS  thesis, Performance Analysis of Incoherent Space Beam Combination for High Energy Laser System as explained by her: 

Today’s world has a great desideratum of the high power source. The laser is one of the solutions in this field. Multiple laser sources are combined with coherent or incoherent beam combination techniques to generate several Kilowatts or even Megawatts of power. The coherent beam combination (CBC) produces high power (~N2 times of individual source beam). Maintaining the coherency among the beams is a challenging task. The power of a single laser source should be limited within Watts in the case of CBC. In contrast, Incoherent Beam Combination (ICBC) is a robust, versatile, and efficient way of achieving high power levels with independent beam sources. Higher atmospheric turbulence affects the beam significantly than the lower turbulent atmosphere. In a higher turbulent atmosphere, the beam spot enlarges, and thereby the average beam intensity on the target decreases. In this thesis, ICBC has been elaborately explained and also analysed for the atmospheric effects. It is shown that Residual Mechanical Jitter (RMJ) of the Beam Directing System (BDS) affects beam pointing accuracy more in lower turbulence than in higher turbulence. The acceptable RMJ for a BDS has also been determined as a function of pointing accuracy for single beam and combination accuracy for multi-beams. Atmospheric condition, as well as other disturbances which degrade laser performances, cannot be avoided. Hence, the user tries to nullify their effects by various mechanisms. The laser focusing mechanism is one of them. A highly focused beam tends to diverge lesser and deliver more intensity to the incident plane after propagating through the atmosphere. Uniform Rectilinear Motion (URM) actuator is the crucial element for changing the laser focusing range dynamically. In this thesis, the one-dimensional URM specification has been evolved based on the requirement of laser focusing accuracy. It is observed that focusing on a lower range demands higher URM accuracy. The URM accuracy requirement has been evaluated as a function of the average intensity of a practical system to a perfect system. In BDS, multiple sensors and laser channels are placed to transmit the laser on the tracked target. It is difficult to synchronise multiple sensors and laser channels for tracking the target within a specific range with various system limitations. The cameras and laser channels must be placed closer to achieve a better target position accuracy and thereby to deliver higher intensity with better beam focusing. Hence, the sensor harmonisation technique needs to be analysed to improve BDS performance. In this thesis, three different BDS architectures are analysed with a different number of channels. The shapes of the beam directing systems are also different. Two methods of sensors harmonisations have been elaborately explained here, i.e., the absence of autoboresighting and the presence of autoboresighting. The laser system with autoboresighting capability is more efficient in tracking the dynamic target than the system without this capability. In case of the absence of autoboresighting facility, it is observed that the initial mechanical boresighting of all sensors at a certain distance will result in better target visibility and tracking capability. It is also observed that the introduction of mechanical tilt for each channel axis of BDS provides better tracking with lesser Steering Mirror (SM) deflection. The fluence requirement for engaging both the static and dynamic objects have been analysed here. The power requirements of the laser system are estimated with available knowledge of lethal object fluence. Power can be enhanced by increasing the number of laser sources. The sequence of operations of the beam combination system for efficiently damaging the object has been proposed in this thesis. Here, the optimum number of laser channels is carried out based on the object’s properties and the system’s capability to minimise laser power wastage. When a large area is required to be protected by a number of laser systems, the position of each system is an essential factor to deliver significant laser energy to each corner of the area. In this thesis, multiple scenarios have been discussed with different separation among the laser systems and analyses the effect of inter-laser system distance in terms of combined average intensity. At the end of this thesis, a comprehensive system specification has been evolved to achieve a higher power density at the incident plane and a better pointing accuracy with lesser SM deflection. This system performance has been improved with multiple beam combination by ICBC. The availability of each subsystem is also taken into consideration. This thesis explains the methodology of designing an efficient state of the art beam combination system.