def t2_leaky():
"""
T2 EDTS layer next to air.
"""
# Create structure
st = LifetimeTmm()
st.set_vacuum_wavelength(lam0)
st.add_layer(2 * lam0, sio2)
st.add_layer(d_etds, edts)
st.add_layer(2 * lam0, air)
st.info()
# Calculate spontaneous emission for leaky and guided modes
result = st.calc_spe_structure_leaky(th_pow=9)
z = result['z']
z = st.calc_z_to_lambda(z)
spe = result['spe']
# Plot spontaneous emission rates
fig, ((ax1, ax2), (ax3, ax4)) = plt.subplots(2, 2, sharex='col', sharey='row', figsize=(15, 7))
ax1.plot(z, spe['TE'], label='TE')
ax1.plot(z, spe['TM_p'], label='TM')
ax1.plot(z, spe['TE'] + spe['TM_p'], label='TE + TM')
ax2.plot(z, spe['TE_lower_full'] + spe['TM_p_lower_full'], label='Fully radiative lower outgoing')
ax2.plot(z, spe['TE_lower_partial'] + spe['TM_p_lower_partial'], label='Partially radiative lower outgoing')
ax2.plot(z, spe['TE_upper'] + spe['TM_p_upper'], label='Fully radiative upper outgoing')
ax3.plot(z, spe['TM_s'], label='TM')
ax4.plot(z, spe['TM_s_lower_full'], label='Fully radiative lower outgoing')
ax4.plot(z, spe['TM_s_lower_partial'], label='Partially radiative lower outgoing')
ax4.plot(z, spe['TM_s_upper'], label='Fully radiative upper outgoing')
# Plot internal layer boundaries
for z in st.get_layer_boundaries()[:-1]:
ax1.axvline(st.calc_z_to_lambda(z), color='k', lw=1, ls='--')
ax2.axvline(st.calc_z_to_lambda(z), color='k', lw=1, ls='--')
ax3.axvline(st.calc_z_to_lambda(z), color='k', lw=1, ls='--')
ax4.axvline(st.calc_z_to_lambda(z), color='k', lw=1, ls='--')
# ax1.set_ylim(0, 4)
# ax3.set_ylim(0, 6)
# ax1.set_title('Spontaneous Emission Rate. LHS n=3.48, RHS n=1.')
ax1.set_ylabel('$\Gamma / \Gamma_0$')
ax3.set_ylabel('$\Gamma /\Gamma_0$')
ax3.set_xlabel('z/$\lambda$')
ax4.set_xlabel('z/$\lambda$')
ax1.legend(title='Horizontal Dipoles', fontsize='small')
ax2.legend(title='Horizontal Dipoles', fontsize='small')
ax3.legend(title='Vertical Dipoles', fontsize='small')
ax4.legend(title='Vertical Dipoles', fontsize='small')
fig.tight_layout()
if SAVE:
plt.savefig('../Images/t2_leaky.png', dpi=300)
plt.show()
def t2_fig4():
"""
Silicon to air semi-infinite half spaces.
"""
# Create structure
st = LifetimeTmm()
st.set_vacuum_wavelength(lam0)
st.add_layer(2 * lam0, sio2)
st.add_layer(d_etds, edts)
st.add_layer(2 * lam0, air)
st.info()
# Calculate spontaneous emission over whole structure
result = st.calc_spe_structure_leaky(th_pow=9)
z = result['z']
spe = result['spe']
# Convert z into z/lam0 and center
z = st.calc_z_to_lambda(z)
# Plot spontaneous emission rates
fig, (ax1, ax2) = plt.subplots(1, 2, sharey='row', figsize=(15, 5))
ax1.plot(z, (spe['TM_p_lower'] + spe['TE_lower']) / (spe['TE'] + spe['TM_p']), label='Lower')
ax1.plot(z, (spe['TM_p_upper'] + spe['TE_upper']) / (spe['TE'] + spe['TM_p']), label='Upper')
ax2.plot(z, (spe['TM_s_lower']) / spe['TM_s'], label='Lower')
ax2.plot(z, (spe['TM_s_upper']) / spe['TM_s'], label='Upper')
# Plot internal layer boundaries
for z in st.get_layer_boundaries()[:-1]:
ax1.axvline(st.calc_z_to_lambda(z), color='k', lw=1, ls='--')
ax2.axvline(st.calc_z_to_lambda(z), color='k', lw=1, ls='--')
# ax1.set_ylim(0, 1.1)
# ax1.set_title('Spontaneous Emission Rate. LHS n=3.48, RHS n=1.')
ax1.set_ylabel('$\Gamma / \Gamma_0$')
ax1.set_xlabel('z/$\lambda$')
ax2.set_xlabel('z/$\lambda$')
ax1.legend(title='Horizontal Dipoles')
ax2.legend(title='Vertical Dipoles')
fig.tight_layout()
if SAVE:
plt.savefig('../Images/t2_fig4.png', dpi=300)
plt.show()
def fig4():
""" n=3 or n=1 (air) to n=1.5 (Erbium deposition) semi-infinite half spaces.
Plot the average total spontaneous emission rate of dipoles as a function of
distance from the interface.
"""
# Vacuum wavelength
lam_vac = 1550
# Plotting units
units = lam_vac / (2 * pi)
# Create plot
f, ax = plt.subplots(figsize=(15, 7))
for n in [1, 3]:
print('Evaluating n={:g}'.format(n))
# Create structure
st = LifetimeTmm()
st.set_vacuum_wavelength(lam_vac)
st.add_layer(4 * units, n)
st.add_layer(4 * units, 1.5)
st.info()
# Calculate spontaneous emission over whole structure
result = st.calc_spe_structure_leaky()
z = result['z']
# Shift so centre of structure at z=0
z -= st.get_structure_thickness() / 2
spe = result['spe']['total']
# Plot spontaneous emission rates
ax.plot(z/units, spe, label=('n='+str(n)), lw=2)
ax.axhline(y=n, xmin=0, xmax=0.4, ls='dotted', color='k', lw=2)
# Plot internal layer boundaries
for z in st.get_layer_boundaries()[:-1]:
# Shift so centre of structure at z=0
z -= st.get_structure_thickness() / 2
ax.axvline(z/units, color='k', lw=2)
ax.axhline(1.5, ls='--', color='k', lw=2)
ax.set_title('Spontaneous emission rate at boundary for semi-infinite media. RHS n=1.5.')
ax.set_ylabel('$\Gamma / \Gamma_0$')
ax.set_xlabel('Position z ($\lambda$/2$\pi$)')
plt.legend()
plt.tight_layout()
if SAVE:
plt.savefig('../Images/spe_vs_n.png', dpi=300)
plt.show()
def spe():
st = LifetimeTmm()
st.set_vacuum_wavelength(lam0)
# Add layers
# st.add_layer(lam0, 1)
st.add_layer(lam0, si)
st.add_layer(lam0, air)
st.add_layer(lam0, si)
# st.add_layer(lam0, 1)
# Get results
result = st.calc_spe_structure_leaky()
z = result['z']
spe = result['spe']
spe_TE = spe['TE_total']
spe_TM_p = spe['TM_p_total']
spe_TM_s = spe['TM_s_total']
# Plot spe rates
fig = plt.figure()
ax1 = fig.add_subplot(211)
ax1.plot(z, spe_TE, label='TE')
ax1.plot(z, spe_TM_p, label='TM')
ax1.plot(z, spe_TE + spe_TM_p, 'k', label='TE + TM')
ax2 = fig.add_subplot(212)
ax2.plot(z, spe_TM_s, label='TM')
ax1.set_title('Spontaneous Emission Rate. LHS n=3.48, RHS n=1.')
ax1.set_ylabel('$\Gamma / \Gamma_0$')
ax2.set_ylabel('$\Gamma /\Gamma_0$')
ax2.set_xlabel('Position in layer (nm)')
ax1.axhline(y=1, linestyle='--', color='k')
ax2.axhline(y=1, linestyle='--', color='k')
# Plot layer boundaries
for z in st.get_layer_boundaries()[:-1]:
ax1.axvline(z, color='k', lw=2)
ax2.axvline(z, color='k', lw=2)
ax1.legend(title='Horizontal Dipoles')
ax2.legend(title='Vertical Dipoles')
plt.show()
def example1():
""" Silicon to air semi-infinite half spaces.
"""
# Vacuum wavelength
lam0 = 1550
n_list = np.linspace(1, 2, 3)
spe_list = []
for n in n_list:
print('Evaluating n={}'.format(n))
# Create structure
st = LifetimeTmm()
st.set_vacuum_wavelength(lam0)
st.add_layer(1550, 1.5)
st.add_layer(1550, n)
# Calculate spontaneous emission over whole structure
result = st.calc_spe_structure_leaky()
z = result['z']
spe = result['spe']['total']
# Only get spe rates in the active layer and then average
ind = np.where(z <= 1550)
spe = spe[ind]
spe = np.mean(spe) - 1.5
spe_list.append(spe)
spe_list = np.array(spe_list)
# Plot spontaneous emission rates vs n
f, ax = plt.subplots(figsize=(15, 7))
ax.plot(n_list, spe_list)
ax.set_title('Average spontaneous emission rate over doped layer (d=1550nm) compared to bulk.')
ax.set_ylabel('$\Gamma / \Gamma_1.5$')
ax.set_xlabel('n')
plt.legend()
plt.tight_layout()
if SAVE:
plt.savefig('../Images/spe_vs_n.png', dpi=300)
np.savez('../Data/spe_vs_n', n=n_list, spe=spe_list)
plt.show()
