converting some optics functions from Simtools

pykat/optics/FabryPerot.py

+# ------------------------------------------------------
+# Moving some utility function from Simtools
+# http://www.gwoptics.org/simtools/
+# to PyKat. Work in progress, currently these
+# functions are not tested.
+# 
+# Andreas 30.11.2014
+# ------------------------------------------------------
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+
+import numpy as np
+
+def cavity_info(Lambda, L, Rc1, Rc2):
+	g1 = 1-L/Rc1
+	g2 = 1-L/Rc2
+	G  = g1*g2
+	G1 = (g1+g2-2*G)
+	
+	k = 2.0*np.pi/Lambda
+
+	zr = np.sqrt( L**2 * G * (1.0-G)/G1**2) 
+	z1 = L * g2 * (1-g1) / G1
+	z2 = L * g1 * (1-g2) / G1
+	w0 = L * Lambda / np.pi * np.sqrt( G * (1-G) / G1**2 )
+	w1 = np.sqrt( L * Lambda /np.pi * np.sqrt( g2 / (g1 * (1-G)) ))
+	w2 = np.sqrt( L * Lambda /np.pi * np.sqrt( g1 / (g2 * (1-G)) ))
+	return [zr, w0, z1, w1, w2]
+	
+def cavity_w1w2_Rc1Rc2(Lambda, L, w1, w2):
+	C = (Lambda*L/np.pi)**2
+	g1 = -1.0 * np.sqrt(1-C/(w1*w2)**2)*(w2/w1)
+	g2 = -1.0 * np.sqrt(1-C/(w1*w2)**2)*(w1/w2)
+	Rc1 = L/(1-g1)
+	Rc2 = L/(1-g2)
+	return [g1, g2, Rc1, Rc2]