Thermal Effects Of Intense Laser Far Field Radiation Optical Material

Laser can be seen in any domain of the society after its rapid development for almost 60 years. Especially with the innovation of the technology, the laser power becomes greater, which also opens a new area of laser applications –the Laser weapons. Most countries have invested much effort in studying the Laser weapons because of their high precision, anti-interference ability and good mobility.This paper mainly focuses on the temperature field of the intense laser radiatng optical materials in the far-field, and analyzes the transmission mechanism of the intense laser in the atmosphere. The equation of the steady-state thermal blooming effects caused by the countinous laser and the equation of the instantaneous-state thermal blooming effects caused by the pulse laser are derived detailedly in the paper. Starting from the mechanism of the intense laser radiatng optical materia ls, this paper describes the transmission characteristics and the impact on the laser beam during transmitting in the materials, and focuses on the analyse of the absorption mechanism of the laser beam after getting into optical materials, and derives the relevant heat conduction equations. The three-dimensional temperature field of Gaussian laser radiating optical materials was derived respectively in the Cartesian coordinate system and in the cylindrical coordinate system, combined with the actual situation. The solutions of the temperature field of the short pulsed laser, the long pulsed laser and the countinous laser radiating optical materials in the far field are also derived in the paper.The main work is as follows: 1. The introduction of the phys ical mechanism of the thermal blooming effects of the intense laser during transmitting in the atmsphere. Starting from the equations of the interaction between the laser and the atmosphere, this paper elaborates the characteristics and the analytical solutions of the steady-state effects of the continuous laser as well as the instantaneous-state thermal blooming effects of the pulsed laser, and analyzes the impact on the steady-state thermal blooming effects of the initial transmit power of the laser, the transimission distance in the atomsphere, the radius of the beam waist and the wind speed by numerical simulation. The difference in the instantaneous-state thermal blooming effects of short-pulse laser and long-pulsed laser is analyzed comparatively.2. The analysis of the physical mechanism of the reflection, transmission and absorption of the optical matericals to the incident beam. This paper focuses on the physical mechanism of the interaction between the strong laser and optical materials, and have a detailed analyse of the intrinsic absorption, self- focusing effects, multi-photon ionization and electron avalanche, impurity defects and nonlinear absorption process.The heat transfer process in the materials caused by the laser beam when the intense laser radiates optical materials is also studied. Base on the Maxwell's equations, the heat conduction equation in Cartesian coordinate system as well as the heat conduction equation with the internal heat source in cylindrical coordinate system are drived.3.Based on the heat conduction equation, the function of the three-dimensional temperature field of the intense laser radiating optical materials is respectively derived in the Cartesian coordinate system and in the cylindrical coordinate system by the integral transform method. The distribution of the temperature field of the optical material Si C is given by analytical method, comparing with the numerical simulation solution of commercial software COMSOL.4. The intense laser is affected by the thermal b looming effects when radiating optical materials in the far field. Based on the instantaneous-state thermal blooming effects, the solutions of the temperature field of the short pulsed laser and the long pulsed laser radiating optical materials in the far field are derived. Based on the steady-state thermal blooming effects in wind and the basic mode of continuous Gaussian beam, the solution of the the temperature field of the continuous laser radiating optical materials is derived, and a detailed analyse is given on the the impact of the emission power of the continuous laser, waist spot radius, the transmission distance and the wind speed on the temperature-rise of the far-field optical material-K9 glass.