JP2546140C - - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser excitation method and a laser excitation apparatus for uniformly exciting a solid-state laser medium from a side by a laser diode. 2. Description of the Related Art A conventional laser excitation apparatus has a configuration as shown in FIG. This laser excitation device includes four laser diodes LD1 around a laser medium 1.
To LD4. These laser diode LD1~LD4 has an optical axis E ₁ to E ₄ of the respective oscillation axes, and the laser diode LD1 and LD3 and the laser diode LD2 and LD4 are opposed to each other. Here, the optical axes E ₁ and E ₃ and the optical axes E ₂ and E ₄ are coincident with each other, and each is the center O of the laser medium 1.
_{Through E} , the optical axes E ₁ and E ₃ are aligned with the arbitrary axis AA ′. In this laser excitation device, excitation is performed from the side of the laser medium 1. FIG. 4 shows a result of an excitation energy density ρ distribution along a cross section of an arbitrary axis AA ′ by the laser excitation device. FIG. 4 shows that the excitation energy density ρ on the vertical axis with respect to the distance in the direction of the axis AA ′ on the horizontal axis is extremely high at the center O _E of the laser medium 1. Incidentally, a laser excitation device having such a plurality of laser diodes is disclosed in Japanese Utility Model Laid-Open No. 2-8160, Japanese Utility Model Laid-Open No. 2-116760, and Japanese Utility Model Laid-open No. 2-116760.
No. 129752 and the like. [0005] In the case of the above-described method of pumping from the side of the laser medium by the laser pumping apparatus, since the respective optical axes of the laser diodes are directed to the center of the laser medium, the excitation energy density is increased. Rise at the center of the laser medium. As described above, when the excitation energy density is extremely high at the center of the laser medium, it causes a hot spot, and there is a problem that the probability of damaging other device components, for example, optical components around the oscillator increases. SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a technical problem of the present invention is to provide a laser excitation method and a laser excitation apparatus capable of performing reasonable excitation without damaging other parts. Is to do. According to the present invention, at least four lasers are provided in a laser excitation method for exciting a laser medium from a side by at least four laser diodes disposed around the laser medium so as to face each other. A laser excitation method is provided in which the respective optical axes of the diodes are discretely arranged so as not to pass through the center of the laser medium and are excited. Further, according to the present invention, in a laser excitation device including a laser medium and at least four laser diodes respectively disposed in a plurality of opposing regions which face each other via the laser medium, at least four laser diodes are provided. In each case, a laser excitation device is obtained which is displaced from the center of the facing region so that the optical axis does not pass through the center of the laser medium. In the laser pumping apparatus of the present invention, at least four laser diodes are provided at positions offset from each other from the opposing region so that the optical axis is shifted from the center of the laser medium. This makes it possible to set the excitation by the laser diode from the side surface of the laser medium so that the excitation energy density in the laser medium becomes uniform. Embodiments The laser excitation method and the laser excitation apparatus of the present invention will be described below in detail with reference to the drawings. First, the outline of the laser excitation method of the present invention will be briefly described. According to the present invention, when the laser medium is excited from the side by four laser diodes disposed opposite to each other around the laser medium, the optical axes of the four laser diodes are discretely arranged so as not to pass through the center of the laser medium. To excite. This makes it possible to make the excitation energy density in the laser medium substantially uniform. FIG. 1 is a sectional view showing a laser excitation device according to an embodiment of the present invention. Also in this laser excitation device, four laser diodes LD1 to LD4 are arranged around the laser medium 1. [0013] These laser diode LD1~LD4 has an optical axis E ₁ to E ₄ of the respective oscillation axis, the laser diode LD1 and LD3 and the laser diode LD2 and LD4 respective optical axes E ₁ each other and, E _The optical axis ₃ and the optical axes E ₂ and E ₄ are displaced from the facing region so as not to pass through the center of the laser medium 1. That is, the arbitrary axis AA 'passes through the center O _E of the laser medium 1 here, and the optical axes E _{1 to} E ₄ respectively depart from the arbitrary axis AA' passing through the center O _E and the orthogonal axis orthogonal thereto. Discretely set at equal intervals. According to this laser excitation device, when the laser medium 1 is excited from the side, the excitation energy density ρ in the laser medium 1 can be made substantially uniform. FIG. 2 shows a result of an excitation energy density ρ distribution along a cross section of an arbitrary axis AA 'by the laser excitation apparatus. From FIG. 2, the horizontal axis A
The excitation energy density ρ on the vertical axis with respect to the distance in the −A ′ direction is the center O of the laser medium 1.
_Although it is slightly higher at _E , it can be seen that most of the portion is almost uniform regardless of the distance in the direction of the axis AA '. Although the embodiment has been described with respect to a laser excitation device provided with four laser diodes LD1 to LD4, the number of laser diodes is not limited to this.
More may be used. As described above, according to the present invention, at least four laser diodes are displaced so that the optical axes of the laser diodes do not pass through the center of the laser medium. , The excitation energy density can be made substantially uniform. As a result, no hot spot is generated, and damage to the optical components around the laser oscillator is prevented with high safety.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a laser excitation device according to one embodiment of the present invention. FIG. 2 shows a result of an excitation energy density distribution along a cross section of an arbitrary axis by the laser excitation device shown in FIG. FIG. 3 is a sectional view showing a conventional laser excitation device. FIG. 4 shows a result of an excitation energy density distribution along a cross section of an arbitrary axis by the laser excitation device shown in FIG. 3; [EXPLANATION OF SYMBOLS] 1 laser medium LD1~LD4 laser diode E ₁ to E ₄ the center of the optical axis O _E laser medium

Claims (1)

1. A laser excitation method for exciting a laser medium from a side by at least four laser diodes disposed around a laser medium so as to face each other, wherein respective optical axes of the at least four laser diodes are provided. And exciting the laser light by discretely arranging them so as not to pass through the center of the laser medium. 2. A laser pumping apparatus comprising: a laser medium; and at least four laser diodes respectively disposed in a plurality of facing regions facing each other with the laser medium interposed therebetween, wherein each of the at least four laser diodes is an optical device. A laser excitation device, wherein the laser excitation device is arranged so as to be displaced from the center of the facing region so that an axis does not pass through the center of the laser medium.