RECENT DRDO DEVELOPMENTS
All Solid-State Nd:YAG Laser
The Institute of Armament
Technology (IAT), Pune, has successfully designed and fabricated an efficient operation of diode-pumped Nd:YAG laser.
Recently, high power laser diode arrays/bars have been found to be promising alternative
to the conventional lamps used for pumping solid-state crystals. In solid-state
lasers, laser crystals are optically pumped by conventional flash lamps or arc/filament
lamps. A number of special features exhibited by these pump laser diodes are: good
spectral match between laser diode emission and peak of the crystal absorption band,
narrow spectral line width, little excess heat generation, spectral brightness
amplification, longer operational lifetime, small size, and lightweight. Thus, the new
class of solid-state lasers, popularly known as diode-pumped solid-state lasers has been
highly efficient, compact, rugged and reliable. Such an all solid-state laser device can
find potential applications not only in military but also in scientific, industrial,
commercial, medical and biomedical areas.
Further effort is on to experiment other Nd-doped laser crystal which can be similarly pumped by the laser diode array. Other non-linear techniques, viz., harmonic generations and parametric oscillation and amplification would be attempted in future for studying other laser raDIATions from diode-pumped solid-state lasers.
Electromechanical Actuation System Servo Controller
The Naval Science & Technological Laboratory (NSTL) , Visakhapatnam, in association with Srijan Controls Drives, Pune; CEERI, Pilani; and Bharat Electronics Ltd, Bangalore, has developed an electromechanical actuation system servo controller for application in light weight torpedo. The actuation system is configured around a brushless DC (BLDC) motor and the electronic hybrid servo controller. The BLDC motor contains rare-earth magnets and Hall Effect sensors for position sensing. The hybrid controller has built-in error amplifier, compensator, electronic communication logic, PWM amplifier, and high power MOSFET/BJTH bridge. The BLOC servo controller development involves: (i) functional design and development of the controller to meet all the requirements of motor bandwidth and power, and (ii) miniaturization of the controller adopting advanced hybridization techniques of die bonding, wire bonding, metal encapsulation techniques, and efficient thermal management to meet the weight and size specifications.