JPS6235276B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser oscillator, and in particular to a laser oscillator that uses a gas such as air or nitrogen to generate a laser element, an excitation light source,
and regarding laser oscillators that require cooling of the condenser.

Conventionally, this type of laser oscillator, as shown in Figure 1, consists of a laser output side reflector 1, a glass face plate 2 for airtightness, a laser crystal 3, and a Xe excitation light source.
an elliptical condenser 5 for effectively focusing the excitation light from the discharge tube 4 and the Xe discharge tube 4 onto the laser crystal 3;
A blower 6 for circulating a gas as a cooling medium, such as nitrogen gas, a fin 7 for taking heat from the circulating nitrogen gas and dissipating the heat to the laser oscillator housing 10, a glass face plate 8, and a total reflection mirror for the laser. 9.

Generally, in a gas-cooled laser oscillator, the area of the passage through which gas circulates cannot be made very narrow due to the characteristics of the blower. That is, when the area of the passage through which gas circulates is narrowed, the pressure drop there increases, the flow rate of gas rapidly decreases, and the cooling power decreases. Therefore, in the conventional example shown in FIG. 1, the elliptical collector 5 is simply an elliptical cylinder in order to widen the area of the nitrogen gas passage, and the areas of the nitrogen gas inlet and outlet are elliptical. Since the area is the same as that of the ellipse of the type condenser 5, the pressure drop against the nitrogen gas is very small, and the configuration is very good from the standpoint of cooling.

However, from the point of view of laser efficiency, which is defined as the ratio of laser light energy to input electrical energy, the elliptical collector 5 is just an elliptical cylinder. Xe discharge tube 4 has a large leakage of excitation light.
The disadvantage is that the excitation light from the laser beam is not effectively focused on the laser crystal 3, resulting in very poor laser efficiency.

Therefore, the conventional laser oscillator shown in Figure 1 uses gas for its cooling system, making it small, lightweight, and highly reliable, but the laser efficiency is low, so the power supply required to supply power to the excitation light source is large. It is unsuitable for reducing size and weight.

The purpose of the present invention is to reduce the leakage of excitation light from the condenser and improve laser efficiency without narrowing the cross-sectional area of the passage of the gas that is the cooling medium, thereby creating a small, lightweight, and highly reliable laser oscillator. There is something to offer.

According to the present invention, a laser crystal, an excitation light source that excites the laser crystal, and a condenser that includes the laser crystal and the excitation light source and focuses excitation light from the excitation light source on the laser crystal are provided. In the laser resonator in which a cooling medium is circulated in the condenser, each has a different length in the axial direction, has a reflective member on the inner surface, and has reflective members on the inner surface perpendicular to the axial direction at both ends. A laser characterized in that two semi-elliptic cylindrical condensers each having a reflective plate are disposed facing each other, and the cooling medium is circulated through a gap formed between the ends of the two semi-elliptic condensers. An oscillator is obtained.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a sectional view of a laser oscillator showing a first embodiment of the present invention, in which a laser output side reflecting mirror 1', a glass face plate 2' for airtightness, a laser crystal 3', and a Xe discharge tube 4' , a blower 6' for circulating nitrogen gas, a fin 7' for taking heat from the circulating nitrogen gas and dissipating the heat to the laser oscillator housing 10', a glass face plate 8', and a total reflection mirror 9' for the laser. A first condenser 11 in the form of a semi-elliptic cylinder, a second condenser 12 in the form of a semi-elliptic cylinder, and reflection plates 13, 13', 13'', 13
It is composed of FIG. 3 is a cross-sectional view of the condenser seen from a direction perpendicular to the cross-sectional direction shown in FIG. 2, and the explanations of the symbols of each part are the same as in FIG. 2.

In FIG. 2, the condenser for effectively concentrating the excitation light from the Xe discharge tube 4' onto the laser crystal 3' is a semi-elliptical condenser 11 equipped with reflectors 13, 13'.
and a semi-elliptical condenser 12 to which reflectors 13'' and 13 are added.The inlet of the nitrogen gas is a gap between the reflectors 13 and 13'', and the outlet of the nitrogen gas is a gap formed by the reflectors 13 and 13''. This is a gap formed by plates 13' and 13. The area of the gap formed by the reflecting plates 13 and 13'' and the gap formed by the reflecting plates 13' and 13 is made wide enough to prevent the pressure drop during the inflow and outflow of nitrogen gas from causing a decrease in the flow rate of the nitrogen gas.Semi-elliptical cylinder. The length of the condenser 11 is the third
As shown in the figure, it is designed to be approximately equal to the light emitting portion of the Xe discharge tube 4' shown by diagonal lines. Since the Xe discharge tube emits light in all directions from the shaded area of the Xe discharge tube 4' shown in FIG.
It is clear that the amount of excitation light leaking from the condenser is significantly reduced in this embodiment compared to the conventional example without 3', 13'', and 13, and therefore the laser efficiency is greatly improved.

Although the basic embodiment has been described above as one embodiment of the present invention, the present invention can also be applied to other modified examples. For example, FIG. 4 is a cross-sectional view of a condenser showing a second embodiment of the present invention,
3″ is a laser crystal, 4″ is a Xe discharge tube, 11′ and 1
2' is a semi-elliptical condenser. In FIG. 4, although the elliptical dimensions of the semi-elliptical condensers 11' and 12' are different, their focal positions are the same, and the laser crystal 3'' and the Xe discharge tube 4'' are arranged at the focal positions. The inlet and outlet of the nitrogen gas are gaps formed by combining the semi-elliptical condensers 11' and 12', and the pressure drop during the inflow and outflow of the nitrogen gas does not cause a decrease in the flow rate of the nitrogen gas. It's widened. Excitation light from the Xe discharge tube 4'' is emitted in all directions, but since the laser crystal 3'' and the Xe discharge tube 4'' are arranged at the focal point of the ellipse, it is always focused on the laser crystal 3''. Therefore, the amount of excitation light leaking from the nitrogen gas inlet and outlet is extremely small, and the laser efficiency is greatly improved compared to the conventional example.

As explained above, the present invention solves the drawbacks of the conventional laser oscillator in which both ends of the condenser are completely open, such that the amount of excitation light leaks from the condenser and the laser efficiency is poor. This is greatly improved because two condensers with different axial lengths and each having reflective members at both ends are placed opposite each other, and the laser efficiency is further improved, so the power supply for the laser oscillator is significantly downsized. This has the effect of reducing power consumption and significantly extending the operating time, especially in laser oscillators that operate on batteries.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional embodiment, FIG. 2 is a sectional view showing a first embodiment of the present invention, and FIG. 3 is a light condensing diagram in the first embodiment of the present invention shown in FIG. FIG. 4 is a cross-sectional view of a condenser in a second embodiment of the present invention. 1, 1'... Laser output side reflecting mirror, 2, 2'...
Glass face plate, 3, 3', 3''...laser crystal, 4,
4', 4''...Xe discharge tube, 5...elliptical condenser, 6,6'...blower, 7,7'...fin,
8, 8'... Glass face plate, 9, 9'... Laser total reflection mirror, 10, 10'... Laser oscillator housing, 1
1, 11', 12, 12'...Semi-elliptical condenser, 1
3, 13', 13'', 13...Reflector.

Claims (1)

[Claims] 1 a laser crystal, an excitation light source that excites the laser crystal, and a laser crystal that includes the laser crystal and the excitation light source;
A laser resonator is provided with a condenser that condenses excitation light from the excitation light source onto the laser crystal, and in which a cooling medium is circulated within the condenser. Two semi-elliptic cylindrical light concentrators are installed opposite each other, and each of the two semi-elliptic cylindrical light concentrators has a reflective plate having a reflecting member provided on the inner surface perpendicular to the axial direction at both ends thereof. A laser oscillator characterized in that the cooling medium is circulated through a gap formed between the ends of the laser oscillator.