基于平面镜多次异面反射调制激光偏振的理论设计

The Theory Design of a Laser Polarization Modulation Device Based on Multiple-Reflection in Plane Mirrors

激光是通过系统传播的光子受激发射放大光而产生,激光以其高亮度、高单色性、高方向性和高相干性等特点,在通信、材料处理、图像记录、医学、数据存储和国防等方面做出了重大贡献.偏振是一种最重要的光学调制,常常用于现代激光技术、成像系统、光信息处理等领域.激光偏振调制是利用光学元器件对激光的偏振态和偏振方向进行调整和改变.激光偏振调制广泛应用在光波导、大地通信、光栅光学光刻等技术方面,目前常见的调制激光偏振的方法是使用偏振片或半波片进行调制,但使用偏振片调制激光偏振时存在严重的光强衰减,激光的利用率大大降低;而使用半波片调制激光偏振时,每一种型号的半波片对应一个光波波长.可见光波段的半波片比较常见,型号种类也较为丰富,但紫外光波段的半波片还比较稀少,且半波片的价格也十分昂贵,这些都导致了传统调制激光偏振方法存在诸如价格高、利用率低、工作范围小等不足.也有一些科研工作者利用光栅镜或复杂的理论论证,提高激光光源的偏振度,但这些方法相对较复杂,对工艺要求高.本文理论设计了一种基于平面镜多次异面反射的激光偏振调制装置,实现对激光偏振方向的成功调制.利用平面镜多次异面反射改变激光的偏振方向,从而实现对激光偏振方向从TE偏振到TM偏振以及从TE偏振到TE偏振的成功调制.该装置具有宽光波段工作、成本低廉等优势.

Laser is achieved by exciting the electronic,vibrational,rotational,or cooperative modes of a material into a nonequilbrium state so that photons propagating through the system are amplified coherently by stimulated emission.Because of its high brightness,collimation,directionality,coherence and well-defined spatial modes,laser is making strong contributions to communications,materials processing,image recording,medicine,data storage and defense.Polarizations,one of the most important optical modulators,are used in modern laser action technique,image-forming system,optical information processing,and so on.The laser polarization modulation uses optical components to change the polarization state and polarization direction of the laser.It is widely used in optical waveguide,communication of the space and ground,optical grating,optical lithography,etc.The laser polarization modulation uses optical components to change the polarization state and polarization direction of the laser.It is widely used in optical waveguide,communication of the space and ground,optical grating,optical lithography,etc.The common method of the laser polarization modulation is to use common polarizer or half wave modulation,but the use of polarizer modulated laser can cause a serious polarization light attenuation and then reduce laser utilization rate.When the half wave is used to modulate laser polarization,each half wave plate corresponds to a wavelength ofvisible light respectively.The half wave plate is relatively common,and types are more abundant,but the half wave plate UV band is still relatively scarce,and prices of half wave plate are also very expensive,which have led to many existing problems of traditional modulation method,such as high price,low utilization rate,small scope of work.Based on the theory of grating mirror or complex research,some researchers improve the degree of polarization of laser light source.But these methods are relatively complex,with high requirement of technology.In this paper,we designed a laser polarization modulation device based on multiple-reflection between two plane mirrors and achieved the successful realization of modulation of the laser polarization direction.By using the plane mirror multiplereflection to change the laser polarization direction,we succeeded in realizing of modulation the laser polarization direction from TE to TM and from TE to TE.The result shows that the device has the characteristics with wide band,low cost and other advantages.