JPS5917874B2 - Excitation light focusing device for dye laser - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for condensing excitation light from a dye laser.

Up to now, light from other continuous wave lasers, such as an argon ion laser, has been used to excite the continuous wave dye laser.

In order to enable oscillation of the dye laser, the power density of the excitation light in the excitation region is normally required to be about 100kW/(V7I).With a pumping laser with an output of several W (watts), it is necessary to have a power density of this order. The diameter of the excitation light beam must be several μ (microns) to realize dye laser oscillation.
The excitation light beam must be narrowed down to about several tens of microns, and therefore a suitable excitation light beam condensing device is required, and for this reason, a plurality of lenses are often used as this device when converting a single excitation light beam. On the other hand, the surface of a dye cell (hereinafter collectively referred to simply as a dye solution) consisting of a medium containing dye molecules, which is the active medium of a dye laser, or a transparent plate that defines the outer shape of this medium, is this surface. In order to prevent reflection loss of the dye laser beam at the dye solution, the incident angle of this laser beam is arranged to form the Brewster angle j0, and accordingly, the incident angle of the excitation light beam to the dye solution is For the purpose of increasing efficiency, the Brewster angle is sometimes set to form an angle close to this angle. 1st
The figure is an explanatory diagram of the function of the dye laser excitation light condensing device (hereinafter simply referred to as the condensing device) consisting of a lens, which is related to the arrangement of the five light beams for the dye solution and excitation described above. be.

The excitation light beam 2 is condensed by the condenser 1 and enters the dye solution 3 at a nearly Brewster angle, exciting the dye molecules.
0 wake up. As a result, optical amplification occurs within the resonator constituted by the reflecting mirrors 4a, 4b, and 4c, and as a result, the dye laser oscillates and a dye laser beam 5 appears. The dye laser beam 5 enters or exits the dye solution 3 at an angle of Brewster i5 between the reflecting mirror 4a and the reflecting mirror 4b. Now, the region in the dye solution 3 where optical amplification is performed is the region in the dye solution 3 that is shared by the dye laser beam 5 corresponding to the eigenstructure of the cavity and the excitation light beam 2. In order to increase the efficiency, it is necessary to make the diameter of the dye laser beam 5 in the dye solution 3 as small as the diameter of the excitation light beam 2 in the same solution.

For this reason, in order to match the area where the excitation light beam 2 is focused (i.e. in the vicinity of the point where the excitation beam 2 is focused) to the appropriate area in the dye solution 3 where the light amplification takes place, it is necessary to An adjustment involving a subtle movement of the position of the condenser 1 is required. Obviously, this movement of the condenser 1 can move the area where the excitation light beam 2 is focused to any position within a certain range. It is desirable that the concentrating device 1 is movable.Such movement is realized by making the condensing device 1 movable along three different directions. The direction is defined, and the direction is a plane that includes both the normal line of the dye solution surface passing through the area where light amplification is performed in the dye solution and the dye laser beam passing through the same area, that is, the plane containing the dye laser beam passing through the same area, that is, the dye solution The only direction parallel to the intersection of the plane of incidence of the dye laser beam and the surface of the dye solution. When fixed, the area where the excitation light beam is concentrated between the dye solutions,
In order to move the dye laser beam into the dye solution in the plane of incidence and parallel to the surface of the dye solution, it is sufficient to move the condenser in only one previously defined direction, which greatly simplifies the adjustment. It is to be done.

On the other hand, in a condensing device that is not movable in the aforementioned directions, achieving a similar movement with respect to the area where the excitation light beam is focused within the dye solution requires the concentrating device to be moved at least differently. This is only possible by moving the objects in two directions and combining them. Therefore, since the region where the excitation light beam is focused moves in a zigzag pattern, adjustment often involves trial and error and requires a great deal of effort. FIG. 2 is a schematic configuration diagram showing one embodiment of the present invention.

In this figure, it is assumed that the plane of incidence of the dye laser beam 5 onto the dye solution 3 coincides with the plane of the paper. Furthermore, the broken line in this figure represents a hidden line due to the excitation light beam 2.
The condensing device 1 is fixed to a holder 6a, and the holder 6a is moved in a direction perpendicular to the plane of the paper by rotating an adjustment screw 7a, resting on a sliding surface 8a with respect to the holder 6b. By rotating the adjustment screw 7b, the holder 6b moves parallel to the paper surface and the surface of the dye solution 3 with respect to the holder 6c while resting on the sliding surface 8b. Accordingly, the condensing device 1 also moves in this direction. Further, by rotating the adjustment screw 7c, the holder 6c is placed on the sliding surface 8c with respect to the holder base material 9 whose relative position to the dye solution 3 is fixed, and is excited in the left and right direction between the paper planes. It moves along the incident direction of the light beam 2, and along with this, the condensing device 1 also moves in the same direction.
According to this embodiment, the area on which the excitation light beam 2 is focused is positioned in the dye solution 3 by rotating the adjusting screw 7c, and then this area is moved within the plane of the paper by rotating the adjusting screw 7a. If you can position it, all that is left is adjusting screw 7.
By simply rotating b, this region can be moved to the most suitable position within the dye solution for light amplification. Although the excitation light beam has been explained above using an example of a continuously incident excitation light beam, the present invention is not limited to this, and can be used for pulsed light beams that are incident singly or intermittently. Good too.

Furthermore, this invention is not limited to continuous-oscillation dye lasers;
It may also be applied to a dye laser that performs pulse oscillation. As described above, in the excitation light focusing device for a dye laser according to the present invention, the focusing device is movable in a direction parallel to the intersection line between the plane of incidence of the dye laser beam entering the dye solution and the surface of the dye solution. This makes it possible to move the area where the excitation light beam is focused parallel to the dye solution surface,
This has the effect of significantly reducing the difficulty associated with the adjustments necessary to find a suitable light collection area.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the function of the excitation light focusing device for dye laser,
FIG. 2 is a schematic diagram showing an embodiment of the present invention.

Claims (1)

[Claims] 1. In an excitation light focusing device for a dye laser that has a lens that focuses a light beam that excites dye molecules that are the active medium of a dye laser, the area where the excitation light beam is focused can be moved parallel to the surface of the active medium. Excitation light focusing device for dye laser.