Search

Array detection method is widely used for measuring the far field laser centroids. The influence of array detector's aperture and dynamic range on the far field laser power was analyzed on the basis of the measurement method and measurement process for the laser spot centroid. The effect of array detector's spatial resolution and spatial duty ratio on the far field laser spot centroid was simulated, and the results were verified by performing experiments, enabling the determination of the technology requirements for the array detector. The expression for the laser spot centroid uncertainty was deduced on the basis of the uncertainty theory and laser spot centroid expression, and the sources of uncertainty were analyzed. The results will be of great importance for measuring the far field laser spot centroids and designing array detectors.

对激光发射系统内的衍射效应进行了模拟计算,利用菲涅耳衍射积分公式的二维傅里叶变换形式,并采用快速傅里叶变换计算方法,讨论了使用快速傅里叶变换计算时二次相位因子满足采样定理的条件,提出了适用于不同传输距离的计算方法,重点对初始光束强度调制对激光传输的影响进行了详细分析.

On the basis of the Lamberts cosine law, the light intensity of a point on the receiving screen behind the diffuse transmission glass screen was theoretically deduced. Combining the application of the diffuse transmission glass screen in the power monitor, the influence of both single-layer glass and multi-layer glasses on the intensity distribution of the incident laser was summarized through numerical simulation. The numerical results show that when the ratio of the radius of the incident laser to the distance from the diffuse transmission screen to the receiving screen is no more than 0.3, the intensity distribution and the caliber of the incident laser couldnt influence the normalized light intensity distribution on the receiving screen. And the normalized light intensity distribution on the receiving screen mainly depends on the distance, which indicates that the arrangement of the glasses or the number of the layers almost have nothing to do with the distribution. This conclusion was proved by the experiment.

We designed a measurement system to measure large size laser beam intensity distribution based on CCD diffuse transmission imaging. The measurement principle is presented. The configuration of the system is introduced. An emphasis is placed on the design of diffuse transmission target. The methods of spot geometry distortion correction and intensity distortion correction are described in detail. After laser spot correction, we can get the real laser beam intensity profile. The test results are given, which validate the correctness of the method. The paper provides a new way to measure quantitatively the profile of large size laser beam with high accuracy.

The intensity distribution of a laser beam (laser beam profile) is one of its most important characteristics because it yields information on the non-uniformity, centroid, centroid jitter and beam quality. A novel measurement method for obtaining a large laser beam intensity distribution based on CCD diffuse transmission imaging is proposed. The measurement principle is presented. The measurement components of the system have been designed. The layout of the system and the design of a diffuse transmission sampling target are emphasized. The methods of correcting geometric and intensity distortion of the spot are described in detail. The method to calibrate the power coefficient is also given. After the laser spot correction, we can obtain the precise laser beam intensity profile as well as the laser power. The presented test results validate the method. In the measurement field of large laser beams, the method can measure the profile with a non-uniformity of less than 1%, and laser power within 2% error compared with the calibration power meter. The measurement system can be used as a standard measurement instrument after being calibrated when manufactured.