JPH01149018A - Acoustooptic element - Google Patents

Abstract

PURPOSE:To assemble a compact optical system easy to produce and to reduce the cost by forming the face opposite to the light incidence face of an acoustooptic medium into many faces and providing a partial reflection film on one of these many faces and providing a total reflection film on the other faces. CONSTITUTION:An acoustooptic medium 1 is provided with a transducer 3 which generates an ultrasonic wave, and the face opposite to a light incidence face 1c of the acoustooptic medium 1 is formed into many faces, and a partial reflection film 5 is provided on one face 1d out of these faces and a total reflection film 6 is provided on the other faces 1b. That is, a part of the diffracted light is emitted from the partial reflection film 5 and the quantity of this diffracted light is monitored. Consequently, this information is fed back to an acoustooptic element to stabilize the quantity of laser light, and the use of optical parts such as a beam splitter 5 on the outside is unnecessary to miniaturize the optical system. Further, a dielectric multilayered film or a metallic film is used and the film thickness is only controlled to produce the partial reflection film 5 and the total reflection film 6. Thus, the workability is good and the cost is reduced.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an acousto-optic device.

BACKGROUND OF THE INVENTION Conventionally, this type of acousto-optic device has had a configuration as shown in FIG. In FIG. 2, 21 is an acousto-optic medium, and one end surface 21a of the medium is equipped with an electric signal source (for example, an oscillator).
A transducer 23 connected to 22 is attached, and a sound absorbing material 24 is attached to the other end surface 21b.

In the above configuration, when a complete signal is applied from the electrical signal source 22 to the transducer 23, an ultrasonic wave 25 is generated and travels through the acousto-optic medium 21 toward the sound absorbing material 24. At this time, the light incidence surface 21c of the acousto-optic medium 21
The incident light 26 is diffracted by the acousto-optic element and output as diffracted light 27 from the light exit surface 21d. Note that 28 is non-diffracted light.

Problems to be Solved by the Invention In such a conventional configuration, the power of the diffracted light is monitored using an acousto-optic element, and the power is fed back to the acousto-optic element to modulate the intensity, thereby keeping the amount of laser light constant. There is a problem in that the light must be partially split using a beam splitter or the like for optical IT-monitoring, which increases the size of the optical system and increases the cost.

The present invention solves these problems by providing a partially reflective film on the acousto-optic medium itself, so that the light intensity monitoring beam 1
The purpose is to derive

Means for Solving the Problems In order to solve the above problems, the acousto-optic element of the present invention includes:
A transducer that generates ultrasonic waves is provided in the acousto-optic medium, and the surface of the acousto-optic medium that faces the light incident surface is multifaceted, and one of the multifaceted surfaces is provided with a partial reflection film, and the remaining surface is provided with a total reflection film. It is equipped with a membrane.

Effect In the above configuration, a part of the diffracted light is emitted from the partially reflective film, and the amount of this diffracted light can be monitored. Therefore, this information can be fed back to the acousto-optic element to stabilize the laser beam, there is no need to use external optical components such as a beam splitter, and the optical system can also be made smaller and lower in cost. Furthermore, since the partially reflective film and the total reflective film can be manufactured by using a dielectric multilayer film or a metal film and only by controlling the film thickness, workability is improved and costs can be further reduced. -Example Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 shows a schematic configuration of an acousto-optic element. In FIG. 1, reference numeral 1 denotes an acousto-optic medium, on one end surface 1a of which is attached a transducer 3 that is connected to an electric signal source (for example, an oscillation u) 2 to generate ultrasonic waves, and on the other end surface 1b is a sound absorbing material. 4 is provided. One side surface 1c perpendicular to the one end surface 1a is used as a light incident surface, and the other side opposite to this light incident surface is protruded in a mountain shape to form two other side surfaces 1d and 1e. There is. That is, the two other side surfaces 1d and le are inclined symmetrically with respect to the light incident surface. A partially reflective film 5 is provided on one of the surfaces 1d, and
A total reflection film 6 is provided on the other surface 1e.

The operation of the friend acousto-optic device configured as described above will be explained below.

The incident light 11 entering from the light incidence surface is an ultrasonic wave 12 generated from the transducer +t,3 inside the acousto-optic medium 1.
is diffracted by the acousto-optic effect. Then, a part 13a of the diffracted light 13 is transmitted through the partial reflection film 5, and the reflected diffracted light 13b that is not transmitted is reflected again by total reflection [6 and exits from the light incident surface. Incidentally, the amount of the t-transmitted diffracted light 13a transmitted through the partially reflective film 5 is monitored, and this information is fed back to the acousto-optic element to control the amount of laser light to be kept constant. Therefore, there is no need to use external components such as a beam splitter, and a compact optical system that makes effective use of space can be achieved, resulting in lower costs. When manufacturing the mirror, the partial reflection film 5, and the total reflection film 6, they are made of a dielectric multilayer film or a metal film,
Since it can be manufactured simply by controlling the film thickness, the work is easy and costs can be reduced. Note that a portion 14a of the undiffracted light 14 is transmitted by the partial reflection film 5, and a portion 14b of the undiffracted light 14 is reflected by the total reflection film 6.

Incidentally, in the above embodiment, there are two surfaces facing the light incident surface, but for example, three or more surfaces may be formed. In this case, a partial reflection film is provided on the negative surface, and a total reflection film is provided on the cutting surface.

Effects of the Invention According to the above configuration of the present invention, the acousto-optic medium has multiple surfaces facing the light incident surface, and one of the multiple surfaces is provided with a partial reflection film, and the remaining surfaces are provided with a total reflection film. Since it is possible to extract a part of the diffracted light and monitor the scene, it is possible to control the amount of laser light at a constant level without using external components such as a beam splitter, making it easy to fabricate. A compact optical system can be assembled and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an acousto-optic device according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of a conventional acousto-optic device. 1... Acousto-optic medium, ld, le... other side,
3...Transducer, 5...Partial reflection film, 6.
... Total reflection film, 11... Incident light, 13... Diffracted light. Agent Yoshihiro Moriki

Claims (1)

[Claims] 1. A transducer that generates ultrasonic waves is provided on an acousto-optic medium, and the surface of the acousto-optic medium that faces the light incident surface is multifaceted, and a partially reflecting film is provided on one of the multifaceted surfaces, and the remaining surfaces are provided with a transducer that generates ultrasonic waves. An acousto-optic element with a total reflection film.