Laser Spatial mode

The distribution of light intensity on cross section of laser beam is called laser transverse mode. The transverse mode is generally regarded as the laser mode. TEMmn is used to present transverse mode. TEM means transverse electromagnetic wave, both m and n are positive integers, respectively standing for ordinal numbers of the points with zero light intensity on x axis and y axis, called mode ordinal number. The diagram below shows light spots of several different laser beam transverse modes. TEM00 mode is also called as the basic mode, the light intensity of any point in its spot will not be zero. If there is a light intensity of any point in spot on x axis is zero, it is called as TEM10 mode; If a light intensity of any point in spot on y axis is zero, TEM01 mode, and so on, mode ordinal numbers m and n are larger, there are more points with zero light intensity in spots. Laser beam with different transverse modes is called as multimode.