Brewster angle and reflectivity of optically nonuniform dense plasmas

Area of Science:

• Plasma Physics
• Condensed Matter Physics
• Laser-Plasma Interactions

Background:

• Understanding the optical properties of matter under extreme conditions, such as shock compression, is crucial for various scientific and technological applications.
• Warm dense matter and nonideal plasmas represent states of matter that are challenging to model due to strong interparticle interactions and complex electronic structures.

Purpose of the Study:

• To theoretically analyze the laser radiation reflectance of shock-compressed plasmas and warm dense matter.
• To investigate the dependence of reflectivity on the angle of incidence for both s- and p-polarized laser light.
• To extend existing theoretical frameworks for calculating optical and electronic properties to describe reflectivity from nonuniform media.

Main Methods:

• A self-consistent approach was extended to calculate optical and electronic properties of warm dense matter and nonideal plasmas.
• Two methods were employed for reflectivity calculations: solving the Helmholtz equation and applying Drude theory of reflection.
• Density-functional theory (DFT) with a longitudinal dielectric tensor was used to obtain the dielectric function.

Main Results:

• Theoretical models were developed for normal and polarized laser incidence on shock-compressed plasmas and warm dense matter.
• The dependence of s- and p-polarized reflectivity on the incidence angle, including the Brewster angle, was analyzed.
• Calculated reflectivity was compared with experimental data for shock-compressed xenon, showing good agreement.

Conclusions:

• The developed theoretical framework accurately describes laser reflectance from broadened, optically nonuniform media.
• The study provides valuable insights into the optical properties of matter under extreme compression.
• The findings validate the theoretical models against experimental observations, enhancing their applicability.