1.5 Example 4: loop and write

In this last example, we will calculate the zeroth order reflection of a grating for a number of distinct polarisations, using a loop. All data will be written to a file. This is how the script looks like:

from rodis import * import math PI = math.pi # rodis data set_lambda(1.0) set_N(10) set_alpha(0.0) set_delta(PI/4) set_psi(0.0) # make device AlAs = Material(2.9 - 0.1j) air = Material(1.0) start = Slab( air(3.) ) ridge = Slab( air(1.) + AlAs(2.)) end = Slab( AlAs(3.) ) grating = Stack( start(1.) +ridge(1.) + end(1.)) # writefile outfile = file("rodis.out",'w') for i in range(-10, 11): set_psi(i*PI/20) grating.calc() print >> outfile, i ,"\t", abs(grating.field().R_TM(0)) outfile.close()

Quite straight foreward. The script will scan the whole range(-10,11) i.e. (-10,-9,-8,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10) That way, we scan the grating in 20 steps, starting with psi= -pi/2 and ending with pi/2. The "rodis.out"-file will be saved in the script's directory. \t inserts a tab, \n inserts a new line.

That's it. So far. In next chapter you can learn some more the gratings and specific rodis-code/terminology.