JPH01310304A - Optical component - Google Patents

Abstract

PURPOSE:To eliminate the need for fine adjustment by providing a 2nd surface which is parallel to an incidence direction and at 45 deg. to a plane parallel to both the incidence direction and a 1st direction and reflects reflected light of incident light from a 1st reflecting surface. CONSTITUTION:A polarizing azimuth rotary prism 2 is constituted by sticking 1st and 2nd right-angled prisms 3 and 4. When polarized light is made incident in an incidence direction (x) shown by an arrow A1, the external surface of a prism 3 which crosses this direction at right angles becomes a 1st incidence surface 31 and the external surface of the prism 3 which is parallel to a direction (y) crossing the incidence direction at right angles and at 45 deg. to the incidence surface 31 becomes a 1st reflecting surface 32. The external surface of the prism which is at right angles to the incidence surface 31 and at 45 deg. to the reflecting surface 32 becomes a 1st projection surface 33. The external surface of a prism 4 which faces this projection surface 33, on the other hand, becomes a 2nd incidence surface 41, the external surface of the prism which is parallel to the incidence direction (x) and at 45 deg. to the incidence surface 41 becomes a 2nd reflecting surface 42, and the external surface of the prism 4 which is perpendicular to the incidence surface 41 and at 45 deg. to the reflecting surface 42 becomes a 2nd projection surface 43.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to optical components such as prisms.

[Conventional technology]

Conventionally, a so-called Fresnel-Rhom prism as shown in FIG. 7 has been known. This fresnel rom prism 1
When linearly polarized light with an azimuth of 45° is incident on the reflecting surface as shown by arrow A1, the inner surface of Fresnel-Rom prism 1
It is reflected twice and emitted as shown by arrow A. At this time, the direction of the emitted light A2 (symbol a in the figure) is orthogonal to the direction of the incident light A1 (symbol a1 in the figure). This means that a phase difference of 1/2 wavelength occurs between the incident light A and the output light A2.
.

This is for the purpose of

[Problem to be solved by the invention]

However, in the above-mentioned conventional technology, if the angle of incidence of the incident light and the direction of the linearly polarized light are changed, the phase difference changes accordingly, so it is necessary to make delicate adjustments. For this reason, Fresnel-Rom prisms were used with instruments equipped with adjustment mechanisms. Furthermore, since the external shape of a Fresnel-Rom prism is usually determined by the refractive index of the material for a specific wavelength, it has not been achromatized in the strict sense.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical component that can rotate the polarization direction between incident light and outgoing light without requiring delicate adjustment or achromatization.

[Means to solve the problem]

The optical component according to the present invention has a direction of incidence of incident light (X direction).
a first reflective surface that is parallel to a first direction (y direction) perpendicular to the plane and makes an angle of 45 degrees with a plane that is parallel to both the incident direction and the first direction; , a second reflective surface forming an angle of 45 degrees with a plane parallel to both the incident direction and the first direction (xy plane) and reflecting the reflected light of the incident light by the first reflective surface. It is characterized by

Here, the first reflective surface is constituted by a total reflection surface of a first right-angle prism having a first entrance surface perpendicular to the direction of the incident light and a first exit surface perpendicular to the first entrance surface. The second reflective surface is a total reflection surface of a second rectangular prism having a second entrance surface facing the first exit surface and a second exit surface orthogonal to the second entrance surface. It may be characterized by being configured.

In addition, a second direction perpendicular to both the incident direction and the first direction
A third reflection that is parallel to the direction (two directions) and forms an angle of 45 degrees with a plane that is parallel to both the incident direction and the second direction, and reflects the reflected light of the incident light by the second reflective surface. It may also be characterized by further comprising a surface.

[Effect]

According to the present invention, when linearly polarized incident light is reflected by the first reflecting surface, a phase difference occurs between the p-polarized light component and the s-polarized light component, and when the linearly polarized incident light is reflected again by the second reflecting surface. A similar phase difference also occurs. Here, the p-polarized light component on the first reflective surface becomes an S-polarized light component on the second reflective surface, and the S-polarized light component on the first reflective surface becomes a p-polarized light component on the second reflective surface. Therefore, the phase difference between the two is canceled by the two reflections, and the planes of polarization of the incident light and the outgoing light as seen from the direction in which the light is received become orthogonal to each other.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to FIGS. 1 to 4 of the accompanying drawings. In addition, in the description of the drawings, the same elements are given the same reference numerals, and redundant description will be omitted.

FIG. 1 is a perspective view of a polarization orientation rotating prism according to an embodiment of the present invention. As shown in the figure (a), the polarization direction rotating prism 2 consists of a first right angle prism 3 and a second right angle prism 4.
It is constructed by pasting together.

Here, if linearly polarized light is incident from the incident direction (X direction) shown by arrow A1 in the figure, the outer surface of the first right-angle prism 3 orthogonal to this incident direction forms the first incident surface 31, The outer surface of the first rectangular prism 3, which is parallel to the y direction (first direction) orthogonal to the incident direction and forms an angle of 45'' with the first incident surface 31, forms the first reflective surface 32. .

and a first reflective surface 3 that is orthogonal to the first incident surface 31;
The outer surface of the first right-angle prism 3 forming an angle of 2 and 45'' forms the first exit surface 33. On the other hand, the outer surface of the second right-angle prism 4 that faces this first exit surface 33 forms the first exit surface 33. The outer surface of the second rectangular prism 4, which is parallel to the incident direction (X direction) and forms an angle of 45'' with the second incident surface 41, forms the second reflective surface 42. , the outer surface of the second rectangular prism 4, which is perpendicular to the second incident surface 41 and forms an angle of 45° with the second reflective surface 42, is the second exit surface 43.
is doing.

Here, as shown in FIG. 1(a), the first rectangular prism 3 and the second rectangular prism 4 may be attached to each other at the first exit surface 33 and the second entrance surface 41,
In this case, a refractive index matching agent such as silicone oil (not shown) is interposed. Further, as shown in FIG. 1(b), a first right angle prism 3 and a second right angle prism 4
may have a certain gap between the first exit surface 33 and the second entrance surface 41. If such a gap is provided, absorption of the bonding agent can be avoided, so that it can be applied to ultraviolet rays and high-power input light.

Next, the operation of the polarization plane rotating prism according to the above embodiment will be explained.

FIG. 2 is a perspective view of a polarization plane rotating prism 2 integrally formed from a single quartz block, and a projected view of its side, bottom, and back surfaces. In the figure, arrow A1 indicates the incident light on the first incident surface 31, and arrow A2 indicates the optical path of the light transmitted through the first incident surface 31 until it is totally reflected on the first reflective surface 32. , arrow A3 indicates the optical path of the light totally reflected by the first reflective surface 32 until it is totally reflected by the second reflective surface 42, and arrow A4 indicates the optical path of the light totally reflected by the second reflective surface 42. The light path until the light passes through the second light emitting surface 43 is shown, and arrow A5 shows the optical path of the light emitted from the second light emitting surface 43. Here, between the incident light A and the output light A5,
Firstly, the optical axis is shifted by the length of optical path A3, secondly, the traveling direction of the light is rotated at right angles, and thirdly, the polarization direction indicated by symbol a1 changes to the polarization direction indicated by symbol a5. There is.

The reason why the polarization direction changes as described above will be explained with reference to FIG.

1A is a side view of the first rectangular prism 3 shown in FIG. 1, and FIG. 1B is a perspective view thereof. Let the refractive index of the first right-angle prism 3 be n, and the first right-angle prism 3, which is a total reflection surface,
If the angle of incidence on the reflecting surface 32 is φ, then φ≧51n-1(1/n)-(1
), the light A2 passes through the first reflective surface 3.
2, it is totally reflected and becomes light A3. However, the substance other than the prism is assumed to be air. Its refractive index is 1.0. The following explanations are treated similarly. Therefore, when the first right angle prism 3 is made of glass with a refractive index of n-1.5, for example, the critical angle φ.

is 42″ or more and satisfies the above conditions.

Here, the amplitude of the reflected light A2 is always equal to the amplitude of the incident light A2, but a phase difference occurs between the p-polarized light component and the S-polarized light component. And the respective phase differences δ and δ are as follows (
2), (3) Formula % Formula % Therefore, the phase difference δ between the two is δ-6-δ... (4) p
It becomes s.

According to the above formula, the incident angle is φ-45″, the refractive index nm is 1.515
2 (BK7 632.8rv), δ ζ39.
5", δ ζ 79.0°, and a phase difference δ-39,5' occurs due to total reflection at the first reflecting surface 32. Therefore, if the first reflection of the first right-angle prism 3 When linearly polarized light having an azimuth of 45'', shown as a1 in FIG. 3(b), is incident on the surface 32, circularly polarized light A', shown as a', is emitted.

However, when a right-angle prism as shown in FIG. At the second reflecting surface 42, it becomes a p-polarized light component. Therefore, the phase differences δ and δ shown in the above-mentioned equations (2) and (3) occur in the opposite way at the second sp reflective surface 42, and as a result, the two cancel each other out, resulting in the sign shown in FIG. Linearly polarized light indicated by a5 is obtained. This means that the polarization directions seen from the direction in which the light is received are orthogonal to each other.

Next, a first modification will be described with reference to FIGS. 4 and 5.

FIG. 4 is a perspective view of the prism 2, which includes a third right-angle prism 5 in addition to the first right-angle prism 3 and the second right-angle prism 4. FIG. This third
The third entrance surface 51 of the right angle prism 5 faces the second exit surface 43 of the second right angle prism 4, and the third reflection surface 52
forms an angle of 45° with this third incident surface 51.

The third exit surface 53 is perpendicular to the third entrance surface 51 and forms an angle of 45° with the third reflection surface 52.

According to this modification, the emitted light A6 is connected to the incident light A1 and the optical path A
Although the axis is shifted by the vector sum of the optical path A4, the traveling directions of the incident light A and the outgoing light A6 are the same. The relationship between the planes of polarization between the incident light A1 and the output light A6 is as shown in FIG. As shown in the figure, the incident light A1
The rotation of the polarization plane of the output destination 〇 by 90'' with respect to the polarization plane of is 45@, (225''), 135@,
(315'').

Next, a second modification will be explained with reference to FIG.

As shown in the figure, the optical component of the present invention may be constructed by combining reflecting mirrors instead of prisms. As shown in the figure, the block 6 has a first reflective surface 61 and a second reflective surface 62.
is formed. Here, the first reflective surface 61 is parallel to the direction (X direction) orthogonal to the incident direction (X direction) of the incident light A1 and forms an angle of 45' with the xy plane, and the second reflective surface 62 receives reflected light A2 in two directions orthogonal to both the x and y directions. The second reflective surface 62 is parallel to the direction of incidence (X direction) and forms an angle of 45° with the xz plane. Furthermore, the first reflective surface 61 and the second
The reflective surface 62 of is coated with a total reflection coating. With this modification as well, rotation of the polarization direction can be realized in the same way as in the embodiment shown in FIG. It goes without saying that the block 6 may be provided with a third reflective surface as in FIG. 4.

In the optical component of the present invention, the characteristics do not change depending on the material, and there is no dependence on the wavelength of incident light. Further, an adjustment mechanism such as a Fresnel-Rom prism is not required at all. [Effects of the Invention] As explained above in detail, in the present invention, when linearly polarized incident light is reflected by the first reflecting surface, the p-polarized component and the S
A phase difference occurs between the polarized light components, and a similar phase difference occurs when the polarized light components are reflected again at the second reflecting surface. Here, the p-polarized light component on the first reflective surface becomes an S-polarized light component on the second reflective surface, and the S-polarized light component on the first reflective surface becomes a p-polarized light component on the second reflective surface. Therefore, the phase difference between the two is canceled by the two reflections, and the polarization directions of the incident light and the outgoing light are orthogonal to each other when viewed from the direction in which the light is received.

Therefore, it is possible to provide an optical component that can rotate the polarization direction between incident light and outgoing light without requiring delicate A adjustment or achromatization. Therefore, it becomes possible to widely apply it to various polarizing optical systems.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of an embodiment of the present invention, FIGS. 2 and 3 are diagrams showing the operation of the above embodiment, and FIG. 4 is a perspective view of a first modification; FIG. 5 is a diagram illustrating the operation of the first modified example, FIG. 6 is a perspective view showing the second modified example, and FIG. 7 is a perspective view of a conventionally known Fresnel-Rom prism. . DESCRIPTION OF SYMBOLS 1... Fresnel-Rom prism, 2... Polarization direction rotating prism, 3... First right angle prism, 31... First incident surface, 32... First reflecting surface, 33...・First
exit surface, 4... second right angle prism, 41... second incident surface, 42... second reflective surface, 43... second
Output surface, 5...Third rectangular prism, 51...Third entrance surface, 52...Third reflection surface, 53... Third
Output surface, 6... block, 61... first reflective surface, 62... second reflective surface. Patent applicant Hamamatsu Photonics Co., Ltd. Representative Patent Attorney
Yoshiki Hase at. The effect of “Jibagshin”! 13r11J It's example @戊

Claims (1)

[Claims] 1. A first reflection parallel to a first direction perpendicular to the direction of incidence of the incident light and forming an angle of 45 degrees with a plane parallel to both the direction of incidence and the first direction. a surface parallel to the incident direction and parallel to the incident direction and a first
An optical component comprising: a second reflecting surface forming an angle of 45 degrees with a plane parallel to both directions, and reflecting light reflected from the incident light by the first reflecting surface. 2. The first reflective surface is a total reflection surface of a first rectangular prism having a first incident surface perpendicular to the direction of the incident light and a first exit surface perpendicular to the first incident surface. The second reflecting surface is a second rectangular prism having a second entrance surface facing the first exit surface and a second exit surface orthogonal to the second entrance surface. The optical component according to claim 1, comprising a total reflection surface. 3. The optical component according to claim 2, wherein the first exit surface and the second entrance surface are bonded to each other via a refractive index matching agent. 4, parallel to a second direction perpendicular to both the incident direction and the first direction, forming an angle of 45 degrees with a plane parallel to both the incident direction and the second direction; The optical component according to claim 1, further comprising a third reflective surface that reflects the reflected light of the incident light by the reflective surface.