Rotationally asymmetric chaotic optical multi-pass cavity
The present invention relates to a rotationally asymmetric chaotic optical multi-pass cavity useful in optical gas sensing spectroscopy, optical delay lines, and laser amplification systems, for example. The cavity may include a single closed mirror having a light reflective surface that is deformed in two orthogonal directions and more particularly, but not exclusively, in the shape of a quadrupole in both horizontal and vertical planes. The cavity includes a light entry port and a light exit port which may be the same or separate ports, as well as a gas inlet and a gas outlet. The optical path length, the beam divergence rate, and the spot pattern are controlled by selecting the cavity deformation coefficients and the input beam direction to achieve the desired beam path and beam quality.
1. A rotationally asymmetric chaotic optical multi-pass cavity, comprising a closed reflecting surface that is deformed in two orthogonal directions and includes an optical inlet port for coupling light into the cavity.
2. The rotationally asymmetric chaotic optical multi-pass cavity according to claim 1 , wherein the reflecting surface has the shape of a quadrupole in the x-y and the y-z planes.
3. The rotationally asymmetric chaotic optical multi-pass cavity according to claim 1 , wherein the optical inlet port is configured to also function as an optical outlet port for coupling light out of the cavity.
4. The rotationally asymmetric chaotic optical multi-pass cavity according to claim 3 , comprising an optical outlet port for coupling light out of the cavity.
5. The rotationally asymmetric chaotic optical multi-pass cavity according to claim 1 , wherein the shape of the reflecting surface is given by
x
=
R
0
[
1
+
ε
yz
cos
(
2
φ
′
)
]
sin
φ
′
[
1
+
ε
xy
cos
(
2
θ
)
]
cos
(
θ
)
1
-
ε
xy
,
y
=
R
0
[
1
+
ε
yz
cos
(
2
φ
′
)
]
sin
φ
′
[
1
+
ε
xy
cos
(
2
θ
)
]
sin
(
θ
)
1
-
ε
xy
,
z
=
R
0
[
1
+
ε
yz
cos
(
2
φ
′
)
]
cos
φ
′
,
where
φ
′
=
tan
-
1
[
(
1
-
ε
xy
)
cot
φ
1
+
ε
xy
cos
(
2
θ
)
]
,
R 0 is the mean cavity radius, and ε xy and ε yz are the deformation parameters.
6. The rotationally asymmetric chaotic optical multi-pass cavity according to claim 5 , wherein both ε xy and ε yz are non-zero.
7. The rotationally asymmetric chaotic optical multi-pass cavity according to claim 5 , wherein ε xy and ε yz have a magnitude sufficient to support quasi-chaotic ray dynamics.
8. The rotationally asymmetric chaotic optical multi-pass cavity according to claim 5 , wherein ε xy is about 0.01 and ε yz is about 0.02.
9. The rotationally asymmetric chaotic optical multi-pass cavity according to claim 1 , wherein the cavity comprises a first cavity half and a second cavity half each having a reflecting surface, the first and second halves being conjoined to provide the single reflecting surface.