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Hi Everyone,

I would like to ask how to use zbftilt? The help document reads a bit confusing: 

This keyword requires the name of the ZBF file and four numbers. The phase of the beam is modified by a phase angle given by θ = ( x – cx )tx + ( y – cy )ty . The cx and cy values are the center of the phase tilt, and tx and ty are the slopes of the tilt in units of radians per lens unit length. The coordinates x and y refer to positions within the beam file, with the center coordinate (x = 0, y = 0) being at the point (nx/2 + 1, ny/2 + 1) where nx and ny are the number of points in the x and y directions. The length units in the ZBF file are converted automatically to the current lens units. The resulting data is written back to the same file name.

 

If I want to rotate an elliptical beam mode by 90°, how should I write it?

Thanks!

Di

I feel this command is used in manipulating the phase of beam mode.

Is there a way to simply exchange x and y so that I can have a horizontally elliptical beam to be a vertically elliptical beam?

Thanks,

Di

@bgdi10262 

 

Not sure it is the most straightforward solution but there might be a programmatic approach to this problem.

@Michael Cheng shared some codes to read binary files, such as ZBF:

I made a “vertical” beam (attached to my reply):

And tried to plot it in Python:

import matplotlib.pyplot as plt
import numpy as np
import struct

filepath=r'C:\Users\davnguyen\Documents\Zemax\POP\BEAMFILES\X1_Y5_OG.ZBF'

with open(filepath, 'rb') as bfile:
    Version = int.from_bytes(bfile.read(4), byteorder='little')
    Nx = int.from_bytes(bfile.read(4), byteorder='little')
    Ny = int.from_bytes(bfile.read(4), byteorder='little')
    IsPol = int.from_bytes(bfile.read(4), byteorder='little')
    Units = int.from_bytes(bfile.read(4), byteorder='little')
    Unused = int.from_bytes(bfile.read(16), byteorder='little')
    Xspacing = struct.unpack('d', bfile.read(8))e0]
    Yspacing = struct.unpack('d', bfile.read(8))e0]
    X_ZPos = struct.unpack('d', bfile.read(8))e0]
    X_ZR = struct.unpack('d', bfile.read(8))e0]
    X_W0 = struct.unpack('d', bfile.read(8))e0]
    Y_ZPos = struct.unpack('d', bfile.read(8))e0]
    Y_ZR = struct.unpack('d', bfile.read(8))e0]
    Y_W0 = struct.unpack('d', bfile.read(8))e0]
    Wave = struct.unpack('d', bfile.read(8))e0]
    Indx = struct.unpack('d', bfile.read(8))e0]
    Rec_Eff = struct.unpack('d', bfile.read(8))e0]
    Sys_Eff = struct.unpack('d', bfile.read(8))e0]

    Ex = np.zeros((Nx, Ny), dtype=complex)
    Ey = np.zeros((Nx, Ny), dtype=complex)

    for xx in range(Nx):
        for yy in range(Ny):
            Ex xx, yy] = struct.unpack('d', bfile.read(8))e0] + 1j*struct.unpack('d', bfile.read(8))e0]

I = np.abs(np.transpose(Ex))**2

plt.figure()
plt.imshow(I, cmap='viridis', extent=e-Nx/2*Xspacing, Nx/2*Xspacing, -Ny/2*Yspacing, Ny/2*Yspacing])
plt.colorbar()
plt.show()

The problem is that the spacing is not uniform in X and Y. You find the spacing in the variables Xspacing and Yspacing. Therefore, before applying a rotation, I believe the sampling should be made uniform first (same spacing in X and Y). Then, you could rotate the beam and write a new ZBF file (I didn’t have time to try, but perhaps this can still be helpful).

Take care,

 

David

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