def cavity(E):
E_p = propagator1.dot(E)
E_p = lens(E_p, f)
E_p *= aberration
E_p = propagator2.dot(E_p)
E_p = lens(E_p, f)
E_p *= aberration
E_p = propagator1.dot(E_p)
return E_p * R * TL
fields = get_fields(cavity, np.sqrt(1-R)*E, n_rt=250)
s = Spectrum(lambda phase: power(rs, fields, phase))
resonance_phases = s.compute_resonances(n_res=1, gain_thres=1)
phases, spectrum = s.spectrum(linspace_kwargs={'focus_width': 1/20})
ax_spectrum.plot((phases - resonance_phases[0])/(2*np.pi), spectrum, label='2w={:.1f}'.format(2*w*1e3))
mode = total_field(fields, resonance_phases[0])
image = ih.image_from_radial(abs(mode) ** 2, N=100, ratio=0.8)
images.append(image)
I = abs(mode)**2
ax_mode.plot(rs/w, I / I.max())
in_field = gaussian(X, Y, 1.0, w, 0, 0).astype(np.complex64)
in_field /= np.sqrt(power(in_field))
# plt.show()
#
# exit()
print('Computing fields.')
fields = get_fields(np.sqrt(1 - R) * in_field, cavity_fun, 50)
print('Fields computed.')
print('Memory used : {:.0f} Mb'.format(fields.nbytes / 1e6))
# total_field = get_total_field(fields, 0)
s = Spectrum(lambda phase: power_at_phase(fields, phase))
print('Computing resonances.')
resonance_phases = s.compute_resonances(n_res=1, gain_thres=0.3)
print('Resonances computed.')
phases, spectrum = s.spectrum()
def plot_field(field, axis=0, axI=None, axP=None, **kwargs):
if axis == 0:
s = np.s_[:, N // 2]
else:
s = np.s_[N // 2, :]
if axI is not None:
axI.plot(abs(field[s])**2, **kwargs)
R1, R2 = 0.98, 0.98
T = 1 - R1
base = np.sqrt(R1 * R2) * np.exp(1j * phase_map)
def power(phase):
u = x[len(x) // 2:]
v = E.E[len(x) // 2:]
b = base[len(x) // 2:]
return np.trapz(x=u,
y=(2 * np.pi * u *
abs(v * np.sqrt(T) /
(1 - b * np.exp(1j * phase)))**2))
S = Spectrum(power_fun=power)
S.compute_resonances()
phases, spectrum = S.spectrum()
fig, ax = plt.subplots()
ax.semilogy(phases, spectrum)
ax.grid(which='both')
ax.grid(which='minor', color=[0.9] * 3, linewidth=0.5)
modes = [
E.transmit(((np.sqrt(T) / (1 - base * np.exp(1j * phase)))))
for phase in S.resonance_phases
]
fig, (axI, axP) = EField.create_figure()
for mode in modes:
# the definition of the cavity function is in the loop as it depends on delta2
def cavity(E):
E_p = E * aberration
E_p = propagator1.dot(E_p)
E_p = lens(E_p, f)
E_p = propagator2.dot(E_p)
E_p = lens(E_p, f)
E_p = propagator1.dot(E_p)
E_p *= displacement_phase_factor
return E_p * R * TL
fields = get_fields(cavity, np.sqrt(1 - R) * E,
n_rt=340) # vérifier avec 2*finesse
s = Spectrum(lambda phase: power_at_phase(rs, fields, phase)
) # helps to find the resonance of the cavity
resonance_phases = s.compute_resonances(n_res=1, gain_thres=0.1)
limits = (resonance_phases[0] - np.pi, resonance_phases[0] + np.pi)
# to plot the spectrum, we vary a phase but the resonane might be badly sampled
# this function creates an adequate linspace to have many points around the resonance
# focus width = width in FSR around the resonance where we want many points
# num focus = how many points in this interval
# limits = range of the scan
phases, spectrum = s.spectrum(linspace_kwargs={
'focus_width': 1 / 30,
'num_focused': 300,
'limits': limits
})