Optical element and system using the same
View Patent ↗An optical element may include a first diffractive structure having a radially symmetric amplitude function and a second diffractive structure having a phase function. The second diffractive structure may serve as a vortex lens. A system employing the optical element may include a light source and/or a detector.
1. A device, comprising:
a light source; and
an optical system configured to transfer light from the light source to an optical fiber, the optical system including a diffractive surface defined by a surface function having a radially symmetric phase function and an angularly symmetric phase function, the surface function being selectively adjustable to control launch conditions and manage reflections.
2. The device as claimed in claim 1 , wherein the radially symmetric phase function is a lens function.
3. The device as claimed in claim 2 , wherein the lens function is given by
π
(
x
2
+
y
2
)
λ
f
,
where ƒ is the focal length of the lens function and λ is a wavelength of the light source.
4. The device as claimed in claim 1 , wherein the angularly symmetric phase function is given by
m
arctan
(
y
x
)
,
where m is a mode number indicating a speed with which a phase of the angularly symmetric phase function is changing.
5. The device as claimed in claim 4 , wherein m equals 3.
6. The device as claimed in claim 1 , wherein the radially symmetric phase function is a polynomial.
7. The device as claimed in claim 6 , the polynomial is a polynomial expansion.