公开(公告)号：US20150292941A1

公开(公告)日：2015-10-15

申请号：US14437794

申请日：2013-10-24

Applicant: CSIR

Inventor： Andrew Forbes ,  Christian Schulze ,  Michael Rudolf Duparré ,  Sandile Ngcobo

IPC: G01J1/42 ,  G01J9/00 ,  H01S3/00 ,  G01J1/04

CPC classification number: G01J1/4257 ,  G01J1/0407 ,  G01J1/0411 ,  G01J1/0437 ,  G01J1/4228 ,  G01J9/00 ,  G01J2009/004 ,  H01S3/0014 ,  H01S3/005 ,  H01S3/08054 ,  H01S3/0815 ,  H01S3/09415

Abstract: A method and apparatus for performing a modal decomposition of a laser beam are disclosed. The method includes the steps of performing a measurement to determine the second moment beam size (w) and beam propagation factor (M2) of the laser beam, and inferring the scale factor (wO) of the optimal basis set of the laser beam from the second moment beam size and the beam propagation factor, from the relationship: wO=w/M2. An optimal decomposition is performing using the scale factor wO to obtain an optimal mode set of adapted size. The apparatus includes a spatial light modulator arranged for complex amplitude modulation of an incident laser beam, and imaging means arranged to direct the incident laser beam onto the spatial light modulator. Fourier transforming lens is arranged to receive a laser beam reflected from the spatial light modulator. A detector is placed a distance of one focal length away from the Fourier transforming lens for monitoring a diffraction pattern of the laser beam reflected from the spatial light modulator and passing through the Fourier transforming lens. The apparatus performs an optical Fourier transform on the laser beam reflected from the spatial light modulator and determines the phases of unknown modes of the laser beam, to perform a modal decomposition of the laser beam.

Abstract translation: 公开了一种用于执行激光束的模态分解的方法和装置。 该方法包括以下步骤：执行测量以确定激光束的第二力矩光束尺寸（w）和光束传播因子（M2），并推断来自激光束的激光束的最佳基准集的比例因子（w0） 二次波束尺寸和波束传播因子，从关系：wO = w / M2。 使用比例因子wO执行最佳分解以获得适应尺寸的最佳模式集合。 该装置包括布置成用于入射激光束的复振幅调制的空间光调制器，以及被配置为将入射激光束引导到空间光调制器上的成像装置。 傅立叶变换透镜被布置成接收从空间光调制器反射的激光束。 离开傅里叶变换透镜放置距离一个焦距的检测器，用于监测从空间光调制器反射并穿过傅里叶变换透镜的激光束的衍射图案。 该装置对从空间光调制器反射的激光束进行光学傅立叶变换，并确定激光束的未知模式的相位，以执行激光束的模态分解。