blazed_profile.py

import numpy as np
def blazed_profile(XX,YY, grating_pitch, wavelength, n1, n0=1, m=1, direction="right", blaze_arrow_angle=0, round_decimals=7): 
    """
    Returns the height profile of a blazed gratin
    
    Args:
        :XX:            x array from meshgrid 
        :YY:            y array from meshgrid 
        :grating_pitch:   pitch of the grating, that sets the diffraction angle and blaze angle
        :wavelength:    wavelength of design
        :n1:            refractive index of the material
        :n0:            refractive index of the background
        :m:            diffraction order
    """

    diffraction_angle = np.arcsin(m*wavelength/grating_pitch)
    blaze_angle = diffraction_angle

    groove_angle = np.arctan(np.sin(blaze_angle)/(n1/n0 - np.cos(blaze_angle)))
    XX -= XX.min()
    YY -= YY.min()
    coordinates = np.cos(blaze_arrow_angle)*XX + np.sin(blaze_arrow_angle)*YY

    coordinates = np.round(coordinates, round_decimals)

    critical_angle = np.arcsin(n0/n1)
    if blaze_angle > critical_angle: 
        print("Blaze angle is greater than critical angle! Will result in total internal reflection")
        
    if direction == "right":
        height = np.tan(groove_angle)*(np.mod(coordinates, grating_pitch) )
    elif direction == "left":
        height = np.tan(groove_angle)*(np.mod(-coordinates, grating_pitch))
    # height = np.tan(groove_angle)*(np.mod(XX- grating_pitch/2, grating_pitch) )
    print("Order m %d, Groove angle: %0.3f deg, Blaze angle: %0.3f deg, height %0.3e"%(m, np.degrees(groove_angle), np.degrees(blaze_angle), height.max()))
    
    return height