JPS6159312A - Optical element - Google Patents

Abstract

PURPOSE:To provide optical functions such as polarization and modulation at a high degree and to reduce the cost of production by constituting the optical element of a crystal having the lamellar domain structure in which the main axes of the index ellipsoid incline with each other. CONSTITUTION:The crystal having the lamellar domain structure in which the main axes of the index ellipsoid incline with each other is used as the optical element. The embodiment of such crystal is enumerated by RbHSeO4, Gd2(MoO4)3, etc. The single crystal of RbHSeO4 is obtd. by a production process consisting in adding Rb2SeO4 and H2SeO4 at an equal mole each to water, heating the same to melt, holding the melt for several days at about 35 deg.C then taking the supernatant, putting the seed crystal of RbHSeO4 therein and resting the same. When incident light 2 is made incident to the optical element 1 manufactured by cutting such single crystal perpendicularly to the (a) axis or (b) axis, the exit light is separated to two kinds (A, A') or four kinds of linearily polarized light (A, A', B, B') according to the incident angle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical element made of a crystal, and more specifically, it is applied to optical control devices such as optical photometry elements, optical deflection elements, optical branching elements, optical switching elements, etc. The present invention relates to an optical element that can be used.

Calcite is used as a polarizing element that utilizes the phenomenon of birefringence. However, calcite has drawbacks such as being expensive, not being able to obtain large crystals of good quality, and being difficult to cut into elements. In addition, KDP, Lj, and T a Oa are used as light modulation elements, but when using these as an optical switch, for example, the element is sandwiched between a polarizer and an analyzer, and an electric field is applied to it. As a result, the plane of polarization is rotated 90 degrees to turn on and off the light, which tends to complicate the mechanism.

-1-1 Momme The present invention was made in view of the above points, and an object thereof is to provide an optical element that highly exhibits optical functions such as polarization and modulation, and is easy to manufacture and inexpensive. shall be.

In order to achieve the above object, the present invention is characterized in that an optical element is constructed from a crystal in which the principal axes of index ellipsoids are mutually inclined and have a layered domain structure.

Hereinafter, a detailed description will be given based on one embodiment of the present invention. The optical element of this example is made of a crystal of RbHSeO4,
The manufacturing method is as follows.

First, take a well-washed Pyrex Erlenmeyer flask (
Capacity: 300cc) with 200cc of pure water and Rb, 5e
Equal moles of a4 and H, 5eO4 are added and dissolved in a water bath whose temperature is controlled at 50°C. Next, the liquid temperature in the water bath was set to 35° C., and the solution was left in that state for 3 days. As a result, crystals presumed to be RbHSeO4 are precipitated at the bottom of the flask, so this supernatant liquid is poured into a well-washed Erlenmeyer flask, seed crystals of RbHSeO4 are added at the same time, and the flask is left for 15 days. This results in a size of approximately 1. Or
A crystal of about nX IQ ImX 10 nwnmn is obtained. When this crystal is analyzed by X-ray diffraction, the space I□(
C1) is a crystal of RbHSeO4 belonging to the triclinic system (0
It is confirmed that the fracture surface is parallel to the 01) plane.

The crystal thus obtained was cut perpendicularly to the a-axis or b-axis to a size of 5 mm x 5 + nm x 1.
The optical element of this example can be obtained by creating a parallel plate crystal element of about mn. In this case, RbHSeO is easy to cut due to its physical properties, and a desired optical element can be easily obtained.

The results of measuring the optical characteristics of the optical element obtained as described above will be explained next. Now, the sample elements cut perpendicularly to the a-axis and the b-axis are referred to as an a-cut plate and a b-cut plate, respectively. As shown in FIGS. 1a and 1b, for these samples 1, the He
-Ne laser 2 was irradiated. The samples 1 shown in both figures are b-cut plates. As a result, when the incident angle α of the laser 2 shown in FIG. 1a is 00,
Both the a-cut plate and the b-cut plate have 2 as emitted light.
Types of linearly polarized light A and A' were obtained. And part 1b
When the incident angle α shown in the figure is 17'', four types of linearly polarized light A, B, A', and B' are obtained.Here, when the incident angle α is changed, α on the board = 24
．． 3" or more, and C6 = 1.5.8° or more for the b-cut plate, it was observed that the emitted light became 43 types of linearly polarized light. This is because the crystals in this example are arranged in parallel layers. It has a domain structure and the refractive index ellipsoids within the domain are alternately tilted at a predetermined angle with respect to the domain wall.

FIG. 2 shows the output angles β (deflection angles) of four types of polarized light obtained in both the a-cut plate and the b-cut plate, plotted against the incident angle α. According to this, it can be seen that the difference in the output angle β between each polarized light is generally larger in the a-cut plate than in the b-cut plate, that is, the degree of separation of the emitted light is greater.

Conventionally, it was known that in -axial and biaxial crystals, the light incident on the crystal is separated into two types of linearly polarized light and emitted, but as in the case of the crystal in this example, it is separated into four types of linearly polarized light. This has not been reported, and it is possible to develop many useful application technologies as optical elements based on this property.

Now, for the b-cut plate, the relative intensity of each polarized light when the incident angle α is 0° and 17″ is shown in Table 1, with the incident light being 100.

Table 1 In Table 1, among the four types of polarized light emitted, the incident angle α
It is shown that the intensity of polarized light A when is 17° is significantly weaker than the others. Here, when an electric field is applied to the b-cut plate, the intensity change in polarized light A, which has the weakest intensity when the incident angle α is 17°, is shown in FIG. 3. According to this, the absolute value of the electric field strength is about 0 to
It can be seen that a large change appears in the intensity of polarized light in the range of 2 kV/an. Therefore, if you use this property,
By simply applying an electric field to the crystal, light can be turned on and off in a sensitive manner, making it possible to obtain a high-performance optical switch at low cost with a simple structure.

The optical properties of the crystal of this example obtained from the above measurement results are as follows.

B. The emitted light is separated into two or four types of linearly polarized light depending on the incident angle.

Mouth, the output angle (deflection angle) is large.

C. The layered domain is sensitively annihilated or regenerated by electric fields, stress, etc., and the obtained linearly polarized light is turned on and off with good responsiveness.

Utilizing the optical properties of Rb) (Sea, crystal in this example described above), optical elements such as useful optical switches, optical branching path elements, optical photometric elements, and optical deflection elements can be manufactured at low cost with a simple structure. can do.

Incidentally, the crystal body is not limited to RbH8eo4, but also Gd2(MoO4)3 and B i4 T j30 x 2 which are crystal bodies having a layered domain structure in which the principal axes of the refractive index ellipsoids are mutually inclined.
It is also possible to obtain optical characteristics similar to those of the above embodiments.

Effects As detailed above, according to the present invention, by using a crystal body having a layered domain structure in which the principal axes of refractive index ellipsoids are mutually inclined as an optical element, excellent optical functions can be exhibited, and It is possible to obtain an optical element that has a simple structure and can be manufactured at low cost.

It should be noted that the present invention is not limited to the two specific embodiments, and it goes without saying that various modifications can be made within the technical scope of the present invention.

[Brief explanation of the drawing]

Figures 1a and 1b are explanatory diagrams showing the state in which the characteristics of an optical element according to an embodiment of the present invention are measured, respectively, and Figure 2 shows changes in the output angle with respect to the incident angle for each polarization. A graph diagram, FIG. 3, is a graph diagram showing intensity changes of polarized light A with respect to electric field strength. (Explanation of symbols) 1: Sample (crystal element) 2: Laser (incident light) A, A'', B, B'': Linearly polarized light (outgoing light) Patent applicant Ricoh Co., Ltd. -=7- Figure 1a Figure 1b Figure 2 Procedural amendment December 14, 1980 Manabu Shiga, Commissioner of the Patent Office 1, Indication of the case 1982 Patent Application No. 17
9442 No. 2, Title of the invention Optical element 3, Relationship to the case of the person making the amendment Patent applicant address 1-3-6 Nakamagome, Ota-ku, Tokyo Name
(674) Rico Co., Ltd. -4, Agent 6, Number of inventions increased by amendment None 7, Subject of amendment Description and drawings 8, Contents of amendment
Contents of amendment 10 The description in the "Claims" column of the specification of the present application is amended as follows as shown in the attached sheet. "1. An optical element characterized by being made of a crystal having a single-layer domain structure in which the principal axes of the refractive index ellipsoids are mutually trnzt. 2. In the above item 1, the crystal is a ferroelectric and ferroelastic material. An optical element characterized in that it is a crystal. 3. An optical element characterized in that in the above item 1, the crystal is made of RbH5eO4." ■0 2 "Detailed Description of the Invention" column in the specification of the present application The description has been amended as follows. 1. In the specification, page 2, lines 18 to 19, "having a mutually inclined layered domain structure" is corrected to "having a mutually inclined layered domain structure". 2. Table 1 published on page 6 of the specification is amended as follows. 3. Correct "Polarized light A with the weakest intensity at 17°" on page 6, line 9 of the specification to "Polarized light A at 17°." ■0 Figure 1b of the drawings attached to this application is amended as shown in red in the attached drawings. (hereinafter ``2) Figure 1b

Claims (1)

[Scope of Claims] 1. An optical element characterized in that the principal axes of the refractive index ellipsoids are mutually inclined and are made of a crystal having a layered domain structure. 2. The optical element according to item 1 above, wherein the crystal is a ferroelectric and ferroelastic crystal. 3. In the above item 1, the crystal is RbHSeO_4
An optical element characterized by comprising: