Propagation Of Flattened Gaussian Beams Research Articles

Propagation characteristics of flattened Gaussian beams through a misaligned optical system with a misaligned annular aperture

The approximate analytical formula for flattened Gaussian beams through a misaligned optical system with a misaligned annular aperture was derived by the extended Huygens–Fresnel principle. Some numerical simulations are illustrated to the effects on the propagation of flattened Gaussian beams by the misaligned annular aperture. To compare the difference between annular apertured system and circular apertured system, the circular apertured system is also studied. The results show that angle misalignments and lateral displacements of aperture create asymmetrical average intensity distribution at receiving plane z=500. The effects on intensity distribution by angle misalignments of annular aperture were small. In annular aperture case, the smooth of intensity distribution was worse with escalating obscure ratio ɛ in near-field; the side-lobes increased and the central lobe decreased with escalating obscure ratio ɛ in far-field. At receiving plane z=500: for circular aperture, the side-lobes decreased, even to be neglected, with the increasing of truncation parameter δ; for annular aperture, the side-lobes increased with the increasing of truncation parameter δ. In addition, it is found that the aligned thin lens can fix asymmetry of intensity distribution which was caused by the misaligned annular aperture.

Propagation analysis of flattened circular Gaussian beams with a circular aperture in turbulent atmosphere

The propagation properties of flattened Gaussian beam with aperture in turbulent atmosphere have been studied by using the extended Huygens–Fresnel principle. From the study and numerical calculation, the effects of aperture on the propagation of flattened Gaussian beams in turbulent atmosphere have been illuminated. It shows that when the value of the truncation parameter δ is bigger, for example δ ⩾ 2 , the effects of aperture on the propagation properties are too small to be neglected. But when the truncation parameter δ is smaller, for example δ < 2 , the effects of aperture are complex. The peak value of the average intensity descends more rapidly and the beam spot spreads quicker with aperture than that without aperture when the propagation distance increases. Meanwhile, with the propagation distance increasing, the average intensity profiles of flattened Gaussian beams gradually convert into Gaussian average intensity profiles. In addition, some limiting cases are also discussed. It agrees with the existing results.

Propagation of flattened Gaussian beams passing through a misaligned optical system with finite aperture

The propagation of flattened Gaussian beams (FGBs) passing though misaligned optical systems with aperture has been studied in detail. The corresponding approximate equation has been derived, where the rectangular aperture function is expanded into a finite sum of complex Gaussian functions. Numerical examples are given to illustrate the application of the propagation equation and the properties of flattened Gaussian beams passing through a misaligned optical system with aperture are discussed.

Propagation of flattened Gaussian beams in apertured fractional Fourier transforming systems

Based on the fact that a hard-edge aperture function can be expanded into a finite sum of complex Gaussian functions, the approximate analytical expressions for the output field distribution of a flattened Gaussian beam passing through the apertured fractional Fourier transforming systems are derived. By using the approximate analytical formulae and diffraction integral formulae, some numerical simulation comparisons are done, and it is shown that our method can significantly improve the numerical calculation efficiency.

Propagation of flattened-Gaussian beams in uniaxial crystals

The propagation of flattened-Gaussian beams(FGBs) in uniaxial crystals is studied based on the paraxial vector theory of the propagation of beams in uniaxially anisotropic media. Analytical propagation equations are derived, which permit us to study the propagation properties of FGBs in unaixal crystals in a simple way. It is shown that the initial circular symmetry of FGBs cannot be kept up, and the state of polarization of FGBs varies during propagation due to the anisotropy of crystals. The spatial evolutions of ordinary and extraordinary components, as well as these in x and y directions in the crystals originating from input FG Bs are illustrated with detailed numerical examples.

Approximate propagation equations of flattened gaussian beams passing through a paraxial ABCD system with hard-edge aperture

The propagation of flattened Gaussian beams through a paraxial optical ABCD system with hard-edge aperture is studied. Approximate closed-form equations of FGBs for the apertured case are derived by means of the expansion of the circ function into a finite sum of complex Gaussian functions. The advantages of the method as compared with the straightforward integration of the Collins formula are discussed and illustrated with numerical examples.

Far-field intensity distribution, M^2 factor, and propagation of flattened Gaussian beams

Explicit expressions for the M(2) factor and field distribution of flattened Gaussian beams that propagate through an unapertured paraxial ABCD system are derived and illustrated with numerical examples. We show that the far-field expression of flattened Gaussian beams can be readily obtained by use of our results.

Propagation of flattened Gaussian beams with rectangular symmetry passing through a paraxial optical ABCD system with and without aperture

The propagation of flattened Gaussian beams (FGBs) passing through a paraxial optical ABCD system has been studied in detail, where both unapertured and apertured cases have been considered. For the unapertured case, a closed-form propagation expression has been derived, and for the apertured case typical numerical examples have been given to illustrate our results and method.