Light detection device
A light detection device includes a flow channel array that is arranged with axes of a plurality of tubes in parallel to each other and constituting a flow channel plane. A light source emits light so that an oscillation direction of an electric field component of the light is parallel to the flow channel plane. An optical axis of the light is included in the flow channel plane, and the optical axis forms a predetermined angle θ 0 with respect to a direction orthogonal to the axes of the plurality of tubes on the flow channel plane, and a light detection system detects light emission from the plurality of tubes.
1 . A light detection device comprising:
a flow channel array in which a plurality of tubes is arranged with axes of the plurality of tubes being parallel to each other, the flow channel array constituting a flow channel plane;
an irradiation optical system including a light source and configured to irradiate light emitted from the light source such that
an oscillation direction of an electric field component of the light is parallel to the flow channel plane,
an optical axis of the light is included in the flow channel plane, and
the optical axis forms a predetermined angle θ 0 with respect to a direction orthogonal to the axes of the plurality of tubes on the flow channel plane; and
a light detection system configured to detect light emission from the plurality of tubes,
wherein the predetermined angle θ 0 satisfies following Formulas 1 and 2 in Mathematical formula 2 with respect to an angle θ 1 of a light beam in a material of the plurality of tubes and an angle θ 2 of a light beam inside the plurality of tubes determined as Mathematical formula 1 based on a refractive index n 0 of a surrounding environment, a refractive index n 1 of the material of the plurality of tubes, a refractive index n 2 of the material inside the plurality of tubes, and the predetermined angle,
[
Mathematical
formula
1
]
n
0
sin
θ
0
=
n
1
sin
θ
1
=
n
2
sin
θ
2
[
Mathematical
formula
2
]
θ
0
>
0.1
n
1
n
2
n
2
2
(
n
1
-
n
0
)
2
+
n
0
2
(
n
2
-
n
1
)
2
Formula
1
(
n
0
+
n
1
)
2
(
n
1
+
n
2
)
2
cos
θ
0
cos
2
θ
1
cos
θ
2
(
n
0
cos
θ
1
+
n
1
cos
θ
0
)
2
(
n
2
cos
θ
1
+
n
1
cos
θ
2
)
2
>
1.
Formula
2
2 . The light detection device according to claim 1 , wherein the predetermined angle θ 0 further satisfies, when a number of the plurality of tubes is N, following Mathematical formula 3
[
Mathematical
formula
3
]
(
16
n
0
n
1
2
n
2
(
n
1
+
n
0
)
2
(
n
1
+
n
2
)
2
)
2
(
c
eil
(
N
2
)
-
1
)
+
(
16
n
0
n
1
2
n
2
(
n
1
+
n
0
)
2
(
n
1
+
n
2
)
2
)
2
(
N
-
c
eil
(
N
2
)
)
1
+
(
16
n
0
n
1
2
n
2
(
n
1
+
n
0
)
2
(
n
1
+
n
2
)
2
)
2
(
N
-
1
)
<
[
16
n
0
n
1
2
n
2
cos
θ
0
cos
2
θ
1
cos
θ
2
(
n
0
cos
θ
1
+
n
1
cos
θ
0
)
2
(
n
2
cos
θ
1
+
n
1
cos
θ
2
)
2
]
.
3 . The light detection device according to claim 1 , wherein the light from the light source is incident on both sides of the flow channel array with the light facing each other.
4 . The light detection device according to claim 1 ,
wherein the plurality of tubes includes capillaries having an inner periphery and an outer periphery being circular in a cross section taken along a plane orthogonal to the axes of the plurality of tubes, and
wherein, for an outer radius R out and an inner radius R in of the plurality of tubes, using a matrix expressed by
[
Mathematical
formula
4
]
R
^
out
=
(
1
0
-
n
2
-
n
0
n
1
1
cos
θ
0
R
out
n
0
n
1
)
,
R
^
out
′
=
(
1
0
-
n
0
-
n
1
n
0
1
cos
θ
1
R
out
n
1
n
0
)
,
R
^
i
n
=
(
1
0
-
n
2
-
n
1
n
2
1
cos
θ
1
R
i
n
n
1
n
2
)
,
R
^
i
n
′
=
(
1
0
-
n
1
-
n
2
n
1
1
cos
θ
2
R
i
n
n
2
n
1
)
,
T
^
1
=
T
^
1
′
=
(
1
(
R
out
-
R
i
n
)
/
cos
θ
1
0
1
)
,
T
^
2
=
(
1
2
R
i
n
/
cos
θ
2
0
1
)
,
a matrix represented by
[
Mathematical
formula
5
]
C
^
=
R
^
out
′
T
^
1
′
R
^
i
n
′
T
^
2
R
^
i
n
T
^
1
R
^
out
is calculated,
a focal length in the direction orthogonal to the axes of the plurality of tubes calculated by the 2 rows-by-1 column component of the matrix of [Mathematical formula 5] is represented by
[
Mathematical
formula
6
]
f
=
-
1
(
C
^
)
21
,
and the focal length satisfies
[
Mathematical
formula
7
]
4
f
>
d
cos
θ
0
with respect to a pitch d of the plurality of tubes in the flow channel array.
5 . The light detection device according to claim 4 , further comprising:
a detection optical system that guides light emitted from the plurality of tubes to the light detection system,
wherein in the detection optical system, a portion where light emission does not occur around a portion where light emission occurs in the plurality of tubes is optically shielded.
6 . The light detection device according to claim 5 ,
wherein the detection optical system includes an optical fiber, and
wherein the optical fiber optically shields the portion where light emission does not occur by guiding only the light emitted from the portion where light emission occurs to a detector.
7 . The light detection device according to claim 5 ,
wherein the detection optical system includes an optical slit member disposed in association with the plurality of tubes, and
wherein the optical slit member optically shields the portion where light emission does not occur.
8 . A light detection device comprising:
a flow channel substrate including a plurality of flow channels arranged with axes being parallel to each other, the flow channel substrate constituting a flow channel plane;
an irradiation optical system including a light source and configured to irradiate light emitted from the light source such that
an oscillation direction of an electric field component of the light is parallel to the flow channel plane,
an optical axis of the light is included in the flow channel plane, and
the optical axis forms a predetermined angle θ 0 with respect to a direction orthogonal to the axes of the plurality of flow channels on the flow channel plane; and
a light detection system configured to detect light emission from the plurality of flow channels,
wherein the predetermined angle θ 0 satisfies
[
Mathematical
formula
8
]
0.1
n
1
❘
"\[LeftBracketingBar]"
n
1
-
n
0
❘
"\[RightBracketingBar]"
<
θ
0
<
arc
sin
(
n
1
2
(
n
0
2
+
n
1
2
)
n
0
4
+
n
0
2
n
1
2
+
n
1
4
)
where a refractive index of a material of the flow channel substrate is presented by n 0 , and a refractive index of a material inside the plurality of flow channels is represented by n 1 .