Sum frequency generation: Difference between revisions
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== Real-time simulation with two external fields == | == Real-time simulation with two external fields == | ||
You go in the <code>FixSymm</code> folder and run again the setup. Then you can put the following input file, that has been generated with the command <code>yambo_nl -u n </code>, in the folder: | You go in the <code>FixSymm</code> folder and run again the setup. Then you can put the following input file, that has been generated with the command <code>yambo_nl -u n </code>, in the folder with the name <code>yambo.in_sfg</code>: | ||
nloptics # [R] Non-linear spectroscopy | nloptics # [R] Non-linear spectroscopy | ||
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% | % | ||
NLverbosity= "low" # [NL] Verbosity level (low | high) | NLverbosity= "low" # [NL] Verbosity level (low | high) | ||
NLtime= 60.00000 | NLtime= <span style="color:red"60.00000 </span> fs # [NL] Simulation Time | ||
NLintegrator= "CRANKNIC" # [NL] Integrator ("EULEREXP/RK2/RK4/RK2EXP/HEUN/INVINT/CRANKNIC") | NLintegrator= "CRANKNIC" # [NL] Integrator ("EULEREXP/RK2/RK4/RK2EXP/HEUN/INVINT/CRANKNIC") | ||
NLCorrelation= "IPA" # [NL] Correlation ("IPA/HARTREE/TDDFT/LRC/LRW/JGM/SEX") | NLCorrelation= "IPA" # [NL] Correlation ("IPA/HARTREE/TDDFT/LRC/LRW/JGM/SEX") | ||
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% | % | ||
Field2_Tstart= 0.010000 fs # [RT Field2] Initial Time | Field2_Tstart= 0.010000 fs # [RT Field2] Initial Time | ||
If you run this input file with the command <code>yambo_nl -F yambo.in_sfg</code>, the code will run 30 simulations for a first laser field with frequency between 2.0 and 8.0 while the frequency of the second field is fixed at 2.0 eV. For this reason we provide you a simple python script to change also the frequency of the second field (in blue in the input). | |||
== Analysis of the results == | == Analysis of the results == |
Revision as of 14:12, 18 April 2024
In this tutorial we will show how to calculate Sum Frequency Generation(SFG) and also Difference Frequency Generation (DFG) in bulk materials.
We suppose you are already familiar with the non-linear response using the Yambo code.
If it is not the case please study the previous tutorials:
Linear response using Dynamical Berry Phase and Real time approach to non-linear response (SHG).
DFT calculations
In this example, we will consider a single layer of hexagonal boron nitride (hBN). If you didn't before you can download input files and Yambo databases for this tutorial here: hBN-2D-RT.tar.gz. and/or follow the instructions to generate the databases here: Prerequisites for Real Time propagation with Yambo
Removing symmetries
In this tutorial we will calculate the SFG along when both fields are in the 'y' direction,
therefore we remove symmetries not compatible with an external field along this direction, with the command ypp_nl -y
:
fixsyms # [R] Remove symmetries not consistent with an external perturbation % Efield1 0.000000 | 1.000000 | 0.000000 | # First external Electric Field % % Efield2 0.000000 | 0.000000 | 0.000000 | # Additional external Electric Field % BField= 0.000000 T # [MAG] Magnetic field modulus Bpsi= 0.000000 deg # [MAG] Magnetic field psi angle [degree] Btheta= 0.000000 deg # [MAG] Magnetic field theta angle [degree] #RmAllSymm # Remove all symmetries RmTimeRev # Remove Time Reversal #RmSpaceInv # Remove Spatial Inversion
Real-time simulation with two external fields
You go in the FixSymm
folder and run again the setup. Then you can put the following input file, that has been generated with the command yambo_nl -u n
, in the folder with the name yambo.in_sfg
:
nloptics # [R] Non-linear spectroscopy NLogCPUs=0 # [PARALLEL] Live-timing CPU`s (0 for all) PAR_def_mode= "balanced" # [PARALLEL] Default distribution mode ("balanced"/"memory"/"workload"/"KQmemory") NL_CPU= "10 1" # [PARALLEL] CPUs for each role NL_ROLEs= "w k" # [PARALLEL] CPUs roles (w,k) DIP_CPU= "" # [PARALLEL] CPUs for each role DIP_ROLEs= "" # [PARALLEL] CPUs roles (k,c,v) DIP_Threads=0 # [OPENMP/X] Number of threads for dipoles NL_Threads=0 # [OPENMP/NL] Number of threads for nl-optics % NLBands 3 | 6 | # [NL] Bands range % NLverbosity= "low" # [NL] Verbosity level (low | high) NLtime= <span style="color:red"60.00000 fs # [NL] Simulation Time NLintegrator= "CRANKNIC" # [NL] Integrator ("EULEREXP/RK2/RK4/RK2EXP/HEUN/INVINT/CRANKNIC") NLCorrelation= "IPA" # [NL] Correlation ("IPA/HARTREE/TDDFT/LRC/LRW/JGM/SEX") NLLrcAlpha= 0.000000 # [NL] Long Range Correction % NLEnRange 2.000000 | 8.000000 | eV # [NL] Energy range (for loop on frequencies NLEnSteps/=0 % NLEnSteps= 30 # [NL] Energy steps for the loop on frequencies % NLrotaxis 0.000000 | 0.000000 | 0.000000 | # [NL] Rotation axis (for the loop on angles NLAngSteps/=0) % NLAngSteps=0 # [NL] Angular steps (if NLAngSteps/=0 field versor will be ignored) NLDamping= 0.200000 eV # [NL] Damping (or dephasing) RADLifeTime=-1.000000 fs # [RT] Radiative life-time (if negative Yambo sets it equal to Phase_LifeTime in NL) #EvalCurrent # [NL] Evaluate the current #FrPolPerdic # [DIP] Force periodicity of polarization respect to the external field HARRLvcs= 18475 RL # [HA] Hartree RL components EXXRLvcs= 18475 RL # [XX] Exchange RL components % Field1_Freq -0.100000 |-0.100000 | eV # [RT Field1] Frequency % Field1_NFreqs= 1 # [RT Field1] Frequency Field1_Int= 1000.00 kWLm2 # [RT Field1] Intensity Field1_Width= 0.000000 fs # [RT Field1] Width Field1_kind= " SOFTSIN" # [RT Field1] Kind(SIN|SOFTSIN| see more on src/modules/mod_fields.F) Field1_pol= "linear" # [RT Field1] Pol(linear|circular) % Field1_Dir 0.000000 | 1.000000 | 0.000000 | # [RT Field1] Versor % Field1_Tstart= 0.010000 fs # [RT Field1] Initial Time % Field2_Freq 2.000000 | 2.000000 | eV # [RT Field2] Frequency % Field2_NFreqs= 1 # [RT Field2] Frequency Field2_Int= 1000.00 kWLm2 # [RT Field2] Intensity Field2_Width= 0.000000 fs # [RT Field2] Width Field2_kind= " SOFTSIN" # [RT Field2] Kind(SIN|SOFTSIN| see more on src/modules/mod_fields.F) Field2_pol= "linear" # [RT Field2] Pol(linear|circular) % Field2_Dir 0.000000 | 1.000000 | 0.000000 | # [RT Field2] Versor % Field2_Tstart= 0.010000 fs # [RT Field2] Initial Time
If you run this input file with the command yambo_nl -F yambo.in_sfg
, the code will run 30 simulations for a first laser field with frequency between 2.0 and 8.0 while the frequency of the second field is fixed at 2.0 eV. For this reason we provide you a simple python script to change also the frequency of the second field (in blue in the input).