The physical-optics approximation and its application to light backscattering by hexagonal ice crystals

Tunneling effects in electromagnetic wave scattering by nonspherical particles: A comparison of the Debye series and physical-geometric optics approximations

“…Within the framework of the PG-O approximation, the near field is computed from the geometric optics laws, and the far field is computed from the near field based on a rigorous near-to-far-field transformation. The aforementioned computational technique is also referred to as the physical optics approximation in some literature [e.g., 13,56]. We use the PG-O approximation throughout the paper to emphasize the role of the geometric optics laws in the near-field calculations, because, in principle, the near field can also be calculated based on the Huygens-Fresnel principle.…”

“…It is customary to examine PG-O accuracy based on direct comparison of approximate PG-O optical properties [7][8][9][10][11][12][13][14][15] with their rigorous counterparts computed from numerically exact methods, including the finitedifference time domain (FDTD) and pseudo-spectral time domain (PSTD) [16][17][18][19], the discrete dipole approximation (DDA) [20][21][22], and the T-matrix method [23][24][25][26][27]. From an application perspective, such a comparison is indispensible for quantifying the PG-O accuracy and delineating its applicability regimes.…”

Beam-splitting code for light scattering by ice crystal particles within geometric-optics approximation

“…In the geometric-optics approximation, scattering of light is consistently formulated in terms of the Stokes parameters as we discussed earlier in details [14,15]. We define the Stokes parameters as…”

The technique for solving the problem of light backscattering by ice crystals of cirrus clouds by the physical optics method for a lidar with zenith scanning

“…Attempts to find the solution were undertaken both using exact methods [9,10] and in the scope of the geometrical optics approximation [11][12][13]. However, only with the development of the physical optics method in 2010s [14][15][16], the problem was successfully solved for classical hexagonal ice crystals of cirrus clouds in the backscattering direction [17][18][19].…”

“…This paper presents a solution of the scattering problem by the physical optics method described in detail in [14]. This method involves tracing all geometrical optics beams propagating inside a crystal and undergoing diffraction at the particle exit.…”