added 4 level atom description

1 files changed, 69 insertions, 0 deletions

diff --git a/four_levels.m b/four_levels.m
new file mode 100644
index 0000000..6c98af1
--- /dev/null
+++ b/four_levels.m
@@ -0,0 +1,69 @@
+1;
+
+Nlevels=4;
+w1=1e9;
+w2=0;
+w_hpf=6800;
+w3=w_hpf;
+w4=w_hpf+.1; % separation of levels |3> and |4> somewhat like Zeeman splitting
+w12=w1-w2;
+w13=w1-w3;
+
+%
+%      -----------  |1>
+%         /     \
+%    E_d /       \ 
+%       /         \ E_p
+%      /           \
+%    -------- |3>   \
+%    --------   |4>  \
+%                     \
+%               ___________ |2>
+
+
+% unperturbed Hamiltonian energy levels
+levels_energy=[ w1, 0,  w3, w4];
+levels_energy=levels_energy*hbar;
+H0=zeros(Nlevels);
+H0=diag(levels_energy);
+%for i=1:Nlevels
+	%H0(i,i)=levels_energy(i);
+%endfor
+
+% decay matrix g(i,j) correspnds to decay from i-->j
+gamma=6;
+gamma_23=.001;
+g_decay=zeros(Nlevels);
+g_decay(1,2)=gamma; %upper level decay
+g_decay(1,3)=gamma; %upper level decay
+g_decay(4,2)=gamma; %upper level decay
+g_decay(4,3)=gamma; %upper level decay
+g_decay(3,2)=gamma_23; % lower levels mixing
+g_decay(2,3)=gamma_23; % lower levels mixing
+
+%defasing matris
+g_deph=0;
+g_dephasing=zeros(Nlevels);
+g_dephasing(1,2)=g_deph;
+g_dephasing(2,1)=g_dephasing(1,2);
+g_dephasing(1,3)=g_deph;
+g_dephasing(3,1)=g_dephasing(1,3);
+g_dephasing(4,2)=g_deph;
+g_dephasing(2,4)=g_dephasing(4,2);
+g_dephasing(4,3)=g_deph;
+g_dephasing(3,4)=g_dephasing(4,3);
+
+
+
+% dipole matrix
+dipole_elements=zeros(Nlevels);
+dipole_elements(1,2)=1;
+dipole_elements(2,1)=dipole_elements(1,2);
+dipole_elements(1,3)=1;
+dipole_elements(3,1)=dipole_elements(1,3);
+dipole_elements(4,2)=1;
+dipole_elements(2,4)=dipole_elements(4,2);
+dipole_elements(4,3)=1;
+dipole_elements(3,4)=dipole_elements(4,3);
+
+