update gaussian beam parameter analysis

src/openqlab/analysis/gaussian_beam.py

@@ -84,13 +84,13 @@ def fit_beam_data(data,
     return results
 
 
-class GaussianBeam():
+class GaussianBeam:
     """
     Represents a complex gaussian beam parameter
     """
 
     def __init__(self, q=0 + 1j, wavelength=1.064e-6):
-        self._lambda = wavelength
+        self._wavelength = wavelength
         self._q = q
 
     @classmethod
@@ -101,7 +101,7 @@ class GaussianBeam():
         """
         Returns the beam parameter after free-space propagation of d
         """
-        return GaussianBeam(self._q + d)
+        return GaussianBeam(self._q + d, self._wavelength)
 
     def get_profile(self, zpoints):
         """
@@ -110,9 +110,17 @@ class GaussianBeam():
         quotient = (self._q.real + zpoints) / self._q.imag
         return self.w0 * np.sqrt(1 + quotient ** 2)
 
+    @property
+    def wavelength(self):
+        return self._wavelength
+
+    @property
+    def q(self):
+        return self._q
+
     @property
     def w0(self):
-        return np.sqrt(self._q.imag * self._lambda / np.pi)
+        return np.sqrt(self._q.imag * self._wavelength / np.pi)
 
     @property
     def z0(self):
@@ -138,7 +146,7 @@ class GaussianBeam():
         """
         Calculate beam divergence (in radian).
         """
-        return np.arctan(self._lambda / np.pi / self.w0)
+        return np.arctan(self._wavelength / np.pi / self.w0)
 
     def __repr__(self):
         return "w0={w0} @ z0={z0}".format(