Simulation and experimental study of laser-induced thermal deformation of spectral beam combination grating

Abstract

The multilayer dielectric (MLD) grating is a critical device for combining multiple laser beams into a single beam in a spectral beam combining (SBC) system. We established a theoretical thermal deformation model of the laser-irradiated MLD grating. Thermal deformation on the surface of the grating is simulated according to a series of parameters including the laser irradiation time, laser power density, and substrate size. To verify the model, we exposed a 960 l/mm, 50×50×1.5 mm3 grating to a laser power density of 3.61 kW/cm2 and observed the temperature change. We used a Twyman-Green interferometer to measure the interference fringes on the grating surface. Based on the Fourier-transform method and a Zernike polynomial fitting method, the real-time grating surface profile is reconstructed. The results show that substrate thickness increase or area decrease can reduce thermal deformation, the average decreases are 18.3% and 19.9%, respectively. The discussion and analysis of the grating thermal deformation are potentially valuable for designing grating to decrease the thermal deformation and improve the combined beam quality of a SBC system.

Dual‐Crossbar Configurated Bi2O2Se Device for Multiple Optoelectronic Applications

“…Simulation: Comsol software was used to simulate the temperature field of Bi 2 O 2 Se/SiO 2 structure and MoS 2 /SiO 2 structure. The heat source is a standard gaussian beam, which is set on the top surface of the material and is determined by the following formula: [62] I (x, y) =…”

Dynamic of Grating Thermal Deformation on Beam Quality for Spectral Beam Combining

“…Yang et al presented the influence of multilayer dielectric grating thermal deformation on the SBC system and the beam quality of the combined beam degraded with increasing incident laser-beam power density [17]. Wang et al investigated the grating deformation under different laser heating times [18]. However, to our best knowledge, the correspondence between irradiation time and the dynamic change of the beam quality has not been found, which is necessary to further understand the dynamic change of beam quality so as to provide a method to reduce thermal deformation and improve the quality of the combined beam.…”

Comparison of spectral beam combining based on reflecting volume Bragg grating, with and without collimating lenses

“…[9][10][11][12] In SBC, a key component used is a diffraction grating, which can diffract light into one (or several) beam(s) traveling in different directions. 13,14 Andrusyak et al proposed an approach for SBC based on a reflecting volume Bragg grating (R-VBG) [15][16][17] in which the optimal values of the incident angles for the two beams directed to the surface of the grating were chosen using the translation/rotation table controlled by a computer system. However, such precise control equipment is not available under normal experimental conditions.…”