Patent ID: 11940349
Assignee: BEIJING U-PRECISION TECH CO., LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 6:
7. The plane grating calibration system of claim 4, wherein the controller performs process on the information about the first measuring light input from the first phase meter and the information about the reference light according to the following formula:, ϕ
    1
   
   =
   
    
     2
     ⁢
     π
     *
     P
     ⁢
     
      M
      1
     
    
    F
   
  
  ,
 

wherein ϕ1 represents a radian value of a phase change of the first measuring light, PM1 represents a value obtained by comparing the first measuring light with the reference light by using the phase plate; and F represents the resolution of the phase plate in the controller,
wherein the controller performs process on the information about the second measuring light input from the second phase meter and the information about the reference light according to the following formula:, ϕ
    2
   
   =
   
    
     2
     ⁢
     π
     *
     P
     ⁢
     
      M
      2
     
    
    F
   
  
  ,
 

wherein ϕ2 represents a radian value of a phase change of the second measuring light, and PM2 represents a value obtained by comparing the second measuring light with the reference light by using the phase plate,
wherein a phase shift of the beam after diffracted by the plane grating is obtained by combining the radian value of the phase changes of the first measuring light and the second measuring light:, x
    m
   
   =
   
    
     (
     
      
       ϕ
       1
      
      +
      
       ϕ
       2
      
     
     )
    
    *
    
     Λ
     
      2
      ⁢
      π
     
    
   
  
  ,
 

wherein xm represents a value of the phase shift of the beam after diffracted by the plane grating under the influence of vibration and air disturbance, and Λ represents a period of the plane grating, and
wherein the controller generates a control command according to a result of preceding process and transmits the control command to the phase modulator, and the phase modulator modulates the laser beam according to the control command to correct an error in the calibration of the plane grating.