Gaussian Optics¶

Gaussian optics.

The module implements:

• Ray transfer matrices for geometrical and gaussian optics.

See RayTransferMatrix, GeometricRay and BeamParameter

• Conjugation relations for geometrical and gaussian optics.

See geometric_conj*, gauss_conj and conjugate_gauss_beams

The conventions for the distances are as follows:

focal distance

positive for convergent lenses

object distance

positive for real objects

image distance

positive for real images

class sympy.physics.optics.gaussopt.BeamParameter(wavelen, z, z_r=None, w=None, n=1)[source]

Representation for a gaussian ray in the Ray Transfer Matrix formalism.

Parameters:

wavelen : the wavelength,

z : the distance to waist, and

w : the waist, or

z_r : the rayleigh range.

n : the refractive index of medium.

Examples

>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.q
1 + 1.88679245283019*I*pi

>>> p.q.n()
1.0 + 5.92753330865999*I
>>> p.w_0.n()
0.00100000000000000
>>> p.z_r.n()
5.92753330865999

>>> from sympy.physics.optics import FreeSpace
>>> fs = FreeSpace(10)
>>> p1 = fs*p
>>> p.w.n()
0.00101413072159615
>>> p1.w.n()
0.00210803120913829


References

property divergence

Half of the total angular spread.

Examples

>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.divergence
0.00053/pi

property gouy

The Gouy phase.

Examples

>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.gouy
atan(0.53/pi)

property q

The complex parameter representing the beam.

Examples

>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.q
1 + 1.88679245283019*I*pi


The radius of curvature of the phase front.

Examples

>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
1 + 3.55998576005696*pi**2

property w

The radius of the beam w(z), at any position z along the beam. The beam radius at $$1/e^2$$ intensity (axial value).

Examples

>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.w
0.001*sqrt(0.2809/pi**2 + 1)


w_0

property w_0

The minimal radius of beam at $$1/e^2$$ intensity (peak value).

Examples

>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.w_0
0.00100000000000000


w

the beam radius at $$1/e^2$$ intensity (axial value).

property waist_approximation_limit

The minimal waist for which the gauss beam approximation is valid.

Explanation

The gauss beam is a solution to the paraxial equation. For curvatures that are too great it is not a valid approximation.

Examples

>>> from sympy.physics.optics import BeamParameter
>>> p = BeamParameter(530e-9, 1, w=1e-3)
>>> p.waist_approximation_limit
1.06e-6/pi

class sympy.physics.optics.gaussopt.CurvedMirror(R)[source]

Ray Transfer Matrix for reflection from curved surface.

Parameters:

R : radius of curvature (positive for concave)

Examples

>>> from sympy.physics.optics import CurvedMirror
>>> from sympy import symbols
>>> R = symbols('R')
>>> CurvedMirror(R)
Matrix([
[   1, 0],
[-2/R, 1]])

class sympy.physics.optics.gaussopt.CurvedRefraction(R, n1, n2)[source]

Ray Transfer Matrix for refraction on curved interface.

Parameters:

R :

Radius of curvature (positive for concave).

n1 :

Refractive index of one medium.

n2 :

Refractive index of other medium.

Examples

>>> from sympy.physics.optics import CurvedRefraction
>>> from sympy import symbols
>>> R, n1, n2 = symbols('R n1 n2')
>>> CurvedRefraction(R, n1, n2)
Matrix([
[               1,     0],
[(n1 - n2)/(R*n2), n1/n2]])

class sympy.physics.optics.gaussopt.FlatMirror[source]

Ray Transfer Matrix for reflection.

Examples

>>> from sympy.physics.optics import FlatMirror
>>> FlatMirror()
Matrix([
[1, 0],
[0, 1]])

class sympy.physics.optics.gaussopt.FlatRefraction(n1, n2)[source]

Ray Transfer Matrix for refraction.

Parameters:

n1 :

Refractive index of one medium.

n2 :

Refractive index of other medium.

Examples

>>> from sympy.physics.optics import FlatRefraction
>>> from sympy import symbols
>>> n1, n2 = symbols('n1 n2')
>>> FlatRefraction(n1, n2)
Matrix([
[1,     0],
[0, n1/n2]])

class sympy.physics.optics.gaussopt.FreeSpace(d)[source]

Parameters:

distance

Examples

>>> from sympy.physics.optics import FreeSpace
>>> from sympy import symbols
>>> d = symbols('d')
>>> FreeSpace(d)
Matrix([
[1, d],
[0, 1]])

class sympy.physics.optics.gaussopt.GeometricRay(*args)[source]

Representation for a geometric ray in the Ray Transfer Matrix formalism.

Parameters:

h : height, and

angle : angle, or

matrix : a 2x1 matrix (Matrix(2, 1, [height, angle]))

Examples

>>> from sympy.physics.optics import GeometricRay, FreeSpace
>>> from sympy import symbols, Matrix
>>> d, h, angle = symbols('d, h, angle')

>>> GeometricRay(h, angle)
Matrix([
[    h],
[angle]])

>>> FreeSpace(d)*GeometricRay(h, angle)
Matrix([
[angle*d + h],
[      angle]])

>>> GeometricRay( Matrix( ((h,), (angle,)) ) )
Matrix([
[    h],
[angle]])

property angle

The angle with the optical axis.

Examples

>>> from sympy.physics.optics import GeometricRay
>>> from sympy import symbols
>>> h, angle = symbols('h, angle')
>>> gRay = GeometricRay(h, angle)
>>> gRay.angle
angle

property height

The distance from the optical axis.

Examples

>>> from sympy.physics.optics import GeometricRay
>>> from sympy import symbols
>>> h, angle = symbols('h, angle')
>>> gRay = GeometricRay(h, angle)
>>> gRay.height
h

class sympy.physics.optics.gaussopt.RayTransferMatrix(*args)[source]

Base class for a Ray Transfer Matrix.

It should be used if there is not already a more specific subclass mentioned in See Also.

Parameters:

parameters :

A, B, C and D or 2x2 matrix (Matrix(2, 2, [A, B, C, D]))

Examples

>>> from sympy.physics.optics import RayTransferMatrix, ThinLens
>>> from sympy import Symbol, Matrix

>>> mat = RayTransferMatrix(1, 2, 3, 4)
>>> mat
Matrix([
[1, 2],
[3, 4]])

>>> RayTransferMatrix(Matrix([[1, 2], [3, 4]]))
Matrix([
[1, 2],
[3, 4]])

>>> mat.A
1

>>> f = Symbol('f')
>>> lens = ThinLens(f)
>>> lens
Matrix([
[   1, 0],
[-1/f, 1]])

>>> lens.C
-1/f


References

property A

The A parameter of the Matrix.

Examples

>>> from sympy.physics.optics import RayTransferMatrix
>>> mat = RayTransferMatrix(1, 2, 3, 4)
>>> mat.A
1

property B

The B parameter of the Matrix.

Examples

>>> from sympy.physics.optics import RayTransferMatrix
>>> mat = RayTransferMatrix(1, 2, 3, 4)
>>> mat.B
2

property C

The C parameter of the Matrix.

Examples

>>> from sympy.physics.optics import RayTransferMatrix
>>> mat = RayTransferMatrix(1, 2, 3, 4)
>>> mat.C
3

property D

The D parameter of the Matrix.

Examples

>>> from sympy.physics.optics import RayTransferMatrix
>>> mat = RayTransferMatrix(1, 2, 3, 4)
>>> mat.D
4

class sympy.physics.optics.gaussopt.ThinLens(f)[source]

Ray Transfer Matrix for a thin lens.

Parameters:

f :

The focal distance.

Examples

>>> from sympy.physics.optics import ThinLens
>>> from sympy import symbols
>>> f = symbols('f')
>>> ThinLens(f)
Matrix([
[   1, 0],
[-1/f, 1]])

sympy.physics.optics.gaussopt.conjugate_gauss_beams(wavelen, waist_in, waist_out, **kwargs)[source]

Find the optical setup conjugating the object/image waists.

Parameters:

wavelen :

The wavelength of the beam.

waist_in and waist_out :

The waists to be conjugated.

f :

The focal distance of the element used in the conjugation.

Returns:

a tuple containing (s_in, s_out, f)

s_in :

The distance before the optical element.

s_out :

The distance after the optical element.

f :

The focal distance of the optical element.

Examples

>>> from sympy.physics.optics import conjugate_gauss_beams
>>> from sympy import symbols, factor
>>> l, w_i, w_o, f = symbols('l w_i w_o f')

>>> conjugate_gauss_beams(l, w_i, w_o, f=f)[0]
f*(1 - sqrt(w_i**2/w_o**2 - pi**2*w_i**4/(f**2*l**2)))

>>> factor(conjugate_gauss_beams(l, w_i, w_o, f=f)[1])
f*w_o**2*(w_i**2/w_o**2 - sqrt(w_i**2/w_o**2 -
pi**2*w_i**4/(f**2*l**2)))/w_i**2

>>> conjugate_gauss_beams(l, w_i, w_o, f=f)[2]
f

sympy.physics.optics.gaussopt.gaussian_conj(s_in, z_r_in, f)[source]

Conjugation relation for gaussian beams.

Parameters:

s_in :

The distance to optical element from the waist.

z_r_in :

The rayleigh range of the incident beam.

f :

The focal length of the optical element.

Returns:

a tuple containing (s_out, z_r_out, m)

s_out :

The distance between the new waist and the optical element.

z_r_out :

The rayleigh range of the emergent beam.

m :

The ration between the new and the old waists.

Examples

>>> from sympy.physics.optics import gaussian_conj
>>> from sympy import symbols
>>> s_in, z_r_in, f = symbols('s_in z_r_in f')

>>> gaussian_conj(s_in, z_r_in, f)[0]
1/(-1/(s_in + z_r_in**2/(-f + s_in)) + 1/f)

>>> gaussian_conj(s_in, z_r_in, f)[1]
z_r_in/(1 - s_in**2/f**2 + z_r_in**2/f**2)

>>> gaussian_conj(s_in, z_r_in, f)[2]
1/sqrt(1 - s_in**2/f**2 + z_r_in**2/f**2)

sympy.physics.optics.gaussopt.geometric_conj_ab(a, b)[source]

Conjugation relation for geometrical beams under paraxial conditions.

Explanation

Takes the distances to the optical element and returns the needed focal distance.

Examples

>>> from sympy.physics.optics import geometric_conj_ab
>>> from sympy import symbols
>>> a, b = symbols('a b')
>>> geometric_conj_ab(a, b)
a*b/(a + b)

sympy.physics.optics.gaussopt.geometric_conj_af(a, f)[source]

Conjugation relation for geometrical beams under paraxial conditions.

Explanation

Takes the object distance (for geometric_conj_af) or the image distance (for geometric_conj_bf) to the optical element and the focal distance. Then it returns the other distance needed for conjugation.

Examples

>>> from sympy.physics.optics.gaussopt import geometric_conj_af, geometric_conj_bf
>>> from sympy import symbols
>>> a, b, f = symbols('a b f')
>>> geometric_conj_af(a, f)
a*f/(a - f)
>>> geometric_conj_bf(b, f)
b*f/(b - f)

sympy.physics.optics.gaussopt.geometric_conj_bf(a, f)[source]

Conjugation relation for geometrical beams under paraxial conditions.

Explanation

Takes the object distance (for geometric_conj_af) or the image distance (for geometric_conj_bf) to the optical element and the focal distance. Then it returns the other distance needed for conjugation.

Examples

>>> from sympy.physics.optics.gaussopt import geometric_conj_af, geometric_conj_bf
>>> from sympy import symbols
>>> a, b, f = symbols('a b f')
>>> geometric_conj_af(a, f)
a*f/(a - f)
>>> geometric_conj_bf(b, f)
b*f/(b - f)

sympy.physics.optics.gaussopt.rayleigh2waist(z_r, wavelen)[source]

Calculate the waist from the rayleigh range of a gaussian beam.

Examples

>>> from sympy.physics.optics import rayleigh2waist
>>> from sympy import symbols
>>> z_r, wavelen = symbols('z_r wavelen')
>>> rayleigh2waist(z_r, wavelen)
sqrt(wavelen*z_r)/sqrt(pi)

sympy.physics.optics.gaussopt.waist2rayleigh(w, wavelen, n=1)[source]

Calculate the rayleigh range from the waist of a gaussian beam.

Examples

>>> from sympy.physics.optics import waist2rayleigh
>>> from sympy import symbols
>>> w, wavelen = symbols('w wavelen')
>>> waist2rayleigh(w, wavelen)
pi*w**2/wavelen