Research On Tolerance High Laser Power Of Liquid Crystal Optical Phased Array Devices

Liquid crystal optical phased arrays are used in laser communication,high-energy laser applications and many other fields due to their high-precision orientation,beam agility,low power consumption,and no mechanical deflection.With the gradual expansion of applications,the requirements for practical applications of liquid crystal optical phased arrays have also gradually increased.The ability to tolerate high-power laser of liquid crystal optical phased has become the focus of research.Once the technical barrier is broken,high-power liquid crystal optical phased arrays will become the mainstream of future science and technology.Based on liquid crystal optical phased array,this paper firstly studies the high power liquid crystal phase shifter and does a lot of work on the liquid crystal device tolerant to high power laser.The main contents are as follows:(1)A thermodynamic model of liquid crystal optical phase shifter and phased array with high power laser incident was constructed.First,the influence of the structure of the liquid crystal device on the resistance to high-power laser was analyzed.Subsequently,the thermodynamic simulation of the device was performed use the COMSOL multiphysics coupling simulation software,mainly from the heat source absorption of the device,the water cooling system,the high thermal conductivity material,and different heat dissipation structures,and the main factors affecting the device during the application of the high power laser were performed.Simulation analysis.Finally,the temperature distribution inside the device under different conditions was obtained by simulation.The phase analysis of the liquid crystal phase shifter and the phase of the phased array was simulated by MATLAB software.The optical phase control of the liquid crystal was also calculated under the high power laser and the influence of the far field distribution of the array.The simulation analysis shows that the heat deposition under heat source absorption is the main reason that affects the device operation.The key to the preparation of high power liquid crystal optical phased arrays is through the use of high thermal conductivity silicon wafers and a good heat dissipation system design.(2)According to the simulation analysis results,targeted for the preparation of high power liquid crystal optical phased array.Firstly,the conductive layer of the device with the most serious heat source absorption was explored.The advantages of the organic polymer transparent conductive film,the graphene transparent conductive film,the indium tin oxide(ITO)transparent conductive film and the nano-metal mesh transparent conductive film in the device were analyzed.Ultra-thin ITO was selected as a conductive layer preparation device for high power liquid crystal optical phased arrays.At the same time,the photo-orientation was substituted for the traditional polyimide(PI)orientation to further reduce the absorption of laser light by the PI.Finally,a silicon-based reflective liquid crystal phase shifter was prepared.At the same time,through a mask design,a liquid crystal optical phased array electrode array that meets the conditions were lithographically produced.(3)The prepared high-power liquid crystal phase shifter device was tested.Under the test platform of the National University of Defense Technology,the prepared quartzbased reflective liquid crystal phase shifter was able to withstand 1064 nm incident laser with a power of 136 W.The temperature of the liquid crystal layer rises by only about 10 degrees,which does not cause irreversible damage to the liquid crystal phase shifter.If the silicon-based reflective liquid crystal phase shifter is tested,the laser-resistant threshold will be increased.The preparation of high power liquid crystal phase shifters lays a good foundation for the preparation of high power liquid crystal optical phased array devices,and it is no longer difficult to prepare high power liquid crystal optical phased arrays.