Propagation Properties Of Gaussian Beams Research Articles

基于高斯光束传播性质的激光相位恢复

基于高斯光束传播性质的激光相位恢复

Propagation properties of Gaussian beam through a asymmetric negative index slab system by transfer matrix

Propagation properties of Gaussian beam through a asymmetric negative index slab system are investigated by transfer matrix. Firstly, transfer matrix related to negative index slab is derived; then the electric field distribution of each region in the system is obtained by ABCD law and the beam focusing both inside and outside the negative index slab is researched. On the paraxial approximation, the propagation properties of Gauss beam through a asymmetric negative index slab system are clearly revealed. When the positive index materials on both sides of the slab are the same, our conclusion can be evolved into the conclusion of a special case, the evolution of conclusion is the same as that of a symmetric negative index slab system.

Propagation properties of Gaussian beam in gradient negative index of refraction material

We apply the ABCD formalism to a gradient negative index medium (NIM) and investigate the propagation and transformation properties of Gaussian beams in this medium. First, we derive the ABCD formalism in a positive gradient NIM and obtain the propagation model. Spatial soliton and the spatial breather propagation in this medium are revealed. Our research suggests that the gradient coefficient has a significant effect on the focusing ability of slab. When the gradient coefficient increases, the quasi-lense effect becomes more prominent and notable. As a result, the focusing ability improves and the beam waist in the focal point shrinks. Second, when Gaussian beams propagate in the negative gradient NIM, the beam waist enlarges as the distance increases. There is neither spatial soliton phenomenon nor breather transmission phenomenon, which is completely different from the propagation characteristics in the positive gradient NIM.

Analysis of measurement error of wind lidar caused by propagation properties of Gaussian beam

The Fabry–Perot Etalon (FPE) is widely used in Doppler wind lidar as frequency discriminator and its performance is certainly affected by the propagation properties of Gaussian beam. The divergence angle of lidar returns affected by the quality factor M2 and magnification of beam expander (MBE) of outgoing laser is firstly discussed. Also, the corresponding sensitivity of system on wind velocity is analyzed. The numerical results show that the divergence angle of lidar returns and FPE transmission varied with height, the resulting sensitivity of system is decreased and the wind velocity error is relatively steady in the far field. Consequently, for the wind lidar using FPE as frequency discriminator, it is supposed that the outgoing laser with both lower beam quality factor M2 and higher MBE are requested, in particularly, the system calibration due to FPE instability must be considered in the near field.

Propagation properties of Gaussian beams through the anamorphic fractional Fourier transform system with an eccentric circular aperture

As known, it is important for the propagation of Gaussian beams in optics. In this paper, based on the expanding a hard-edge circular aperture function as a finite sum of complex Gaussian functions and the scalar Rayleigh–Sommerfeld diffraction formula, an approximation analytical solution for Gaussian beams propagating through the anamorphic fractional Fourier transform system with an eccentric circular aperture is performed. Then, the detailed numerical calculation for the two-dimensional Gaussian beams in the above-mentioned optical system is presented. The simulation also shows that different location and size of aperture result in the change of diffracted field, including location, intensity and width. All these characteristics help us understand Gaussian beams propagation better.

Propagation properties of Gaussian beams through cat eye optical lens with center shelter

Based on the method of matrix decomposition and expanding the aperture function into a sum of finite complex Gaussian functions, the analytical propagation equations of Gaussian beams through cat eye optical lens with center shelter are derived. Through numerical calculation, the laws governing the variation of the intensity distribution of the cat eye reflected light with the center shelter ratio and the diameter of the detector at the focal plane are given. The results show that the diffraction series and the intensity of the cat eye reflected light depend strongly on the center shelter ratio. As a further extension, it is found that the eye optical lens can be interpreted as a spatial filter, and different filter effect can be obtained by changing the pinhole size.

高斯光束的传输特性对法布里-珀罗标准具分光的激光雷达影响

高斯光束的传输特性对法布里-珀罗标准具分光的激光雷达影响

ABCD matrix formalism for propagation of Gaussian beam through left-handed material slab system

We apply a simple ABCD matrix formalism to investigate beam propagation in left-handed material (LHM) slab systems. Firstly, we derive the expressions for the matrix elements for a single LHM slab. Based on the ABCD matrix, we obtain the field distributions both inside and outside the LHM slab, and the conditions for focusing and phase compensation of the Gaussian beam. Secondly, the derived ABCD law is applied to analyze the propagation properties of Gaussian beams through various cascaded LHM slab systems. The corresponding focusing and phase compensation conditions of the Gaussian beam are also obtained. Our theoretic formalism may be applied as a compact and effective tool for the research of light beam propagation in complex LHM slab systems, since it avoids the complicated integral operation.

Vibrating knife-edge technique for measuring the focal length of a microlens

A vibrating knife-edge technique is proposed for measuring the focal length of a microlens. The technique is based on the propagation properties of Gaussian beams. A laser beam with a Gaussian intensity profile is focused in front of the microlens under test. After being transmitted through the microlens, the beam propagates toward a detector, which consists of a photodiode that is half blocked by a knife-edge. The photodiode integrates approximately half the intensity of the transmitted beam. The knife-edge vibrates sinusoidally with small amplitude in a plane normal to the direction of propagation. Our analysis shows that the output signal at the photodiode consists of a dc component plus a temporal sinusoidal signal whose amplitude is proportional to the focal length of the microlens. After system calibration, the focal length is measured with an envelope detector or a lock-in amplifier.

Instrument for collimating and expanding Gaussian beams for underwater laser imaging systems

Based on the propagation properties of Gaussian beams, a new scheme for an instrument for collimating and expanding (ICE) Gaussian beams for underwater laser imaging systems is proposed, as well as a method for its optimal design. The aberration of a Gaussian beam passing through the ICE is calculated approximately. A design example of the aligning system for the underwater laser imaging system with synchronous scanning is presented.