Pos to delay

utility functions for laser data processing

Laser_utils.py

+def positionToDelay(pos, origin=0, invert = False, reflections=1):
+    ''' converts a motor position in mm into optical delay in picosecond
+        Inputs:
+            pos: array-like delay stage motor position
+            origin: motor position of time zero in mm
+            invert: bool, inverts the sign of delay if True
+            reflections: number of bounces in the delay stage
+
+        Output:
+            delay in picosecond
+    '''
+    c_ = 299792458 *1e-9 # speed of light in mm/ps
+    x = -1 if invert else 1
+    return 2*reflections*(pos-origin)*x/c_
+    
+def degToRelPower(x, theta0=0):
+    ''' converts a half-wave plate position in degrees into relative power
+        between 0 and 1.
+        Inputs:
+            x: array-like positions of half-wave plate, in degrees
+            theta0: position for which relative power is zero
+            
+        Output:
+            array-like relative power
+    '''
+    return np.sin(2*(x-theta0)*np.pi/180)**2