Dear Amrita,

If you want to plot a given propagating mode, you just need to calculate your wave function and then choose your mode as follows:

calculate the wave function
wf=kwant.wave_function(sys, energy)

 choose the modes coming from a given lead (lead 0 for example):

and then choose for example the mode number 5:


you can plot it as follows:,my_mode)

I hope this helps.

On Tue, Mar 13, 2018 at 11:07 PM, amrita chapagain <> wrote:
Hi all,

Thank you for addressing my previous query.

I am trying to plot first few incoming transverse waveguide modes on lead 0. I am wondering whether it is possible to plot all incoming modes on Lead 0. kwant.physics.modes gives me PropagatingModes and Stabilized modes but I want to select just first few modes of incoming flux. 
Here is the sample code of my system

import kwant                     
import numpy as np               
from matplotlib import pyplot
from numpy import sqrt
from math import *

# Define the shape -------------------
def shape(pos):
    x, y = pos
    return (np.abs(2.0*x)<=L)&(np.abs(y)<W1/2.0)

a      = 1;     
t      = 1;    
E0L    = 0*t   
L      = 10;  # Length of the
W1   = 30;  # Width on the left

# Define geometry
sys0 = kwant.Builder()
lat  = kwant.lattice.square(a)
# Define onsite energies and couplings
sys0[lat.shape(wv_shape,(0,0))] = E0     # To make all sites the same
sys0[lat.neighbors()]           = t

# Left lead
left_lead = kwant.Builder(kwant.TranslationalSymmetry([-1,0]))  
left_lead[(lat(0,y) for y in range(int(-W1/2+1),int(W1/2)))] = E0L
left_lead[lat.neighbors()] = t                                                             
# Right lead
right_lead = kwant.Builder(kwant.TranslationalSymmetry([1,0])) 
right_lead[(lat(0,y) for y in range(int(-W1/2+1),int(W1/2)))] = E0L
right_lead[lat.neighbors()] = t                                  
sys = sys0.finalized()

def plot_conductance(sys, energies):

    data = []
    for energy in energies:
        smatrix = kwant.smatrix(sys, energy)
        data.append(smatrix.transmission(2, 0)+smatrix.transmission(1,2) )
        #transmission from left 2 leads to right lead

    pyplot.plot(energies, data)
    pyplot.xlabel("energy [t]")
    pyplot.ylabel("conductance [e^2/h]")
energies=[-3+i*0.02 for i in range(100)]

Abbout Adel