constants.py: unit conversions

Former-commit-id: 61ecddf9bb1d4c4a0355bad5edcae435a160aeb2

qpms/constants.py

@@ -0,0 +1,33 @@
+# unit conversions, mostly for standalone usage
+# TODO avoid importing the "heavy" qpms parts
+from scipy.constants import epsilon_0 as ε_0, c, pi as π, e as eV, hbar as ℏ, mu_0 as μ_0
+pi = π
+μm = 1e-6
+nm = 1e-9
+# "SCUFF FREQUENCY UNIT"
+SU = 3e14
+SCUFF_OMEGAUNIT = SU
+
+#freqs = freqs_weirdunits * c / μm
+
+def nm2eV(lambda_nm, n = 1):
+    return 2*π*c/(n * lambda_nm * nm) / (eV / ℏ)
+
+def eV2nm(e_eV, n = 1):
+    return 2*π*c/(n * e_eV * (eV/ℏ)) / nm
+
+def SU2eV(e_SU):
+    '''
+    Scuff frequency units to eV.
+    '''
+    return e_SU * SU / (eV / ℏ)
+
+def eV2SU(e_eV):
+    return e_eV * (eV / ℏ) / SU
+
+def SU2nm(e_SU, n = 1):
+    return 2*π*c/(n * e_SU * SU) / nm
+
+def nm2SU(lambda_nm, n = 1):
+    return 2*π*c/(n * lambda_nm * nm) / SU
+