JPH0334873B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a laser oscillation device using a cylindrical laser medium. (Prior Art) A laser oscillation device is known in which a polygonal optical path is formed by a plurality of laser tubes, a total reflection mirror, and an output mirror. FIG. 7 is a plan view showing a conventional ring laser device. (Problems to be Solved by the Invention) Although the laser oscillation device described above can lengthen the optical path, it becomes large in size as a whole. An object of the present invention is to provide a laser oscillation device using a cylindrical laser medium that allows a longer resonant optical path length than a polygonal laser medium. (Means for Solving the Problem) In order to achieve the above-mentioned object, a laser oscillation device using a cylindrical laser medium according to the present invention has a laser oscillation device that uses a cylindrical laser medium that is almost optically transparent. A reflective surface and an entrance/exit window, or an entrance window and an exit window are provided, and an external reflecting mirror is provided close to the window, so that the light incident through the window is reflected many times internally and then exits from the window. In this way, an optical resonator is formed between the inner and outer mirrors. (Example) Hereinafter, the present invention will be described in more detail with reference to the drawings and the like. FIG. 1 is a perspective view showing an embodiment of a laser oscillation device using a cylindrical laser medium according to the present invention. On the outer peripheral surface of a transparent cylindrical optical medium 1 such as ruby, Nd:YAG, or laser glass, there is a cylindrical total reflection surface 1a whose inner surface is a total reflection surface, and an entrance/exit window 1.
b, 1c are provided. The total reflection surface 1a is formed by aluminum vapor deposition to efficiently reflect light. An entrance/exit window 1b is provided on the outside of the cylindrical laser medium 1,
A beam splitter 2 is arranged so as to bisect the angle formed by the angle 1c, and an output mirror 5 consisting of a total reflection mirror 3 and a semi-transparent mirror is arranged in relation to the beam splitter 2. Due to the arrangement of these optical systems, counterclockwise and clockwise reflection paths are formed within the cylindrical optical medium 1. FIG. 2 is a plan view showing an example of a reflection path.
FIG. 3 is a side view of the same. This embodiment employs optical excitation, and the laser medium is excited by excitation light sources 6 and 7 from both end faces of the cylinder. In Figure 2, the clockwise light is → 2 (reflection) → 1
b (transmission) → M ₃ → M ₄ ~ M ₁₁ → 1c (transmission) → 2
(Transmission) → 5 (Transmission) The light is emitted following the path. For counterclockwise light, → 2 (transmission) → 1c (transmission) →
Follow the path M ₁₁ ~ M ₃ → 1b (transmission). Note that M ₁ to M ₁₁ indicate total reflection surfaces. Figure 4 shows that when the incident angles α, γ, and the exit angles β, δ are changed little by little with respect to the tangential direction at the light incidence and exit points, there is a certain The number of reflections and number of rotations that have a relationship will be taken. If it is desired to change the optical path system c→c' which is currently incident at α, simply by moving the incident light position in parallel from c→d, the incident angle becomes γ and an optical path from d→d' is obtained. An example of an optical path corresponding to an incident angle is shown. DEG: Angle between the normal line of the virtual cylindrical surface and the incident ray at the point of incidence M: Number of rotations of light reflection on the cylindrical surface from the point of incidence until exit N: Total number of reflections + 2 DIS: When the radius is 1 Length (chord) between two points of reflection ADIS: Total distance between the incident point and the exit point when the radius is 1

[Table] Figure 5 schematically shows the optical path when the incident angle is 2°. For example, light incident at an angle of 89° (90°-1°) to the tangent to a disk with a radius of 100 mm will be reflected 179 (181-2) times,
It rotates 88 (=M) and returns to a range of 1/1000 of the radius, that is, a range of ±0.05 mm from the point of incidence. At this time, the total travel distance of the light is 35993.0mm. By appropriately selecting the incident angle conditions in this manner, it is possible to further increase the number of reflections, that is, the number of reflection rotations within the disk. This means that it is possible to achieve high efficiency as a laser. FIG. 6 is a sectional view showing still another embodiment of a laser oscillation device using a cylindrical laser medium according to the present invention. In this embodiment, a pair of discharge electrodes E ₁ ,
_E2 is provided. Although the cylindrical laser medium has been explained in detail above, this concept can be easily extended to spheres as well. (Effects of the Invention) As explained in detail above, the laser oscillation device using the cylindrical laser medium according to the present invention has an optical reflection surface facing the inner surface and an entrance/exit window on the outer periphery of the cylindrical laser medium, or an entrance window. An exit window is provided, and an external reflecting mirror is provided close to the window, so that the light incident through the window is reflected many times inside and then exits from the window. The structure is configured to form an optical resonator. Therefore, the optical system becomes simple, stable, small and lightweight. Since the external size is small and the optical path length can be increased, high efficiency can be expected. It is also possible to construct a laser gyro using a laser having this structure. Since the resonant wavelength changes due to the optical path difference, it is possible to detect the rotational angular velocity of the system.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a cylindrical laser oscillation device according to the present invention. FIG. 2 is a plan view showing the optical path within the laser medium. FIG. 3 is a side view of the same. FIG. 4 is a schematic diagram showing the relationship between the angle of incidence and the path. FIG. 5 is a diagram showing an example of a schematic study of light input/output angles and optical paths. FIG. 6 is a side view showing another embodiment using another laser medium. FIG. 7 is a plan view showing a conventional ring laser device. 1...Cylindrical medium, 1a...Cylindrical reflection surface of the columnar medium, 1b...Clockwise incidence surface (counterclockwise exit surface), 1c...Counterclockwise incidence surface (clockwise exit surface), 2
...beam splitter, 3...total reflection mirror, 5...
output mirror.

Claims (1)

[Claims] 1. An optical reflection surface facing the inner surface and an entrance/exit window, or an entrance window and an exit window are provided on the outer periphery of a cylindrical laser medium, and an external reflecting mirror is provided close to the window, so that the light incident through the window is A laser oscillation device using a cylindrical laser medium configured to be repeatedly reflected many times and emitted from the window to form an optical resonator between the inner and outer mirrors.