starting to add ligo tools to pykat

pykat/GWdetectors/aLIGO.py

+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+#import pykat.exceptions as pkex
+import numpy as np
+import math
+import copy
+import warnings
+import cmath
+
+nsilica=1.44963098985906
+
+#class aLIGO():
+
+
+def BSpath(thickness, n=nsilica, angle=45.0):
+    """
+    Compute optical path length in BS substrate, default
+    parameters assume angle of incidence of 45 deg and fused
+    silica substrate.
+    thickness: substrate thickness [m]
+    n: index of refraction of substrate
+    angle: angle of incidence (in vacuum) [deg]
+    """
+    
+    angle_subst = math.asin(math.sin(math.radians(angle))/n)
+    L = thickness / math.cos(angle_subst) 
+    
+    return math.degrees(angle_subst), L