JPS60231376A - Gas laser - Google Patents

Abstract

PURPOSE:To make it possible to change an oscillating wavelength by changing crystals simply without disassembling a laser, by rotating a holder, to which several kinds of ion crystals are attached, by external operation. CONSTITUTION:A holder 4 is rotatably attached to the inside of a crystal changing chamber 5. By rotating a stepping motor 6, arbitrary one of four kinds of ion crystals 3, which are attached to the holder 4, can be positioned at the end part of a copper pipe 1. Exciting infrared rays are inputted through a window 7, transmitted through the crystal 3, which is located at an input coupling position, and inputted to the inside of the copper pipe 1. Ammonia gas is excited by the infrared rays. Of the far infrared rays emitted from the excited ammonia gas, the light with cirtain wavelength is reflected by the crystal 3 with high reflectivity. The light with said wavelength is reflected between a reflecting mirror 2 and the crystal 3 and goes back and forth. The light is intensified and transformed into a laser beam, which is emitted through the central hole of the reflecting mirror 2.

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a gas laser whose oscillation wavelength can be switched. The structure is such that light is reflected back and forth between these two reflectors, and when the gas is excited by an appropriate method, a specific wavelength is emitted when the excited gas molecules return to a low energy level state. While the light travels back and forth between the two reflectors, the light of the specific wavelength is enhanced by inducing other excited gas molecules to return to a lower level. When there are several types of transitions when the gas returns to a lower energy level, it is possible to oscillate light with a wavelength corresponding to each transition. Therefore, one of the reflectors placed at both ends of the gas pipe should have a reflection characteristic that is high in the range that includes only one of the wavelengths at which oscillation is possible, and transparent in the other wavelength ranges. However, by replacing the reflector described above with one with other characteristics, it is possible to obtain laser light of several different wavelengths with one gas laser. .

For example, in molecular gas lasers in the far-infrared region, ion crystals made of KCl caps are almost transparent to infrared light, but since they exhibit high reflectance in the far-infrared wavelength region, such ion crystals are used. It has been shown that single-wavelength laser oscillation can be caused by using it as the above-mentioned reflector, and that the oscillation wavelength can be selected by changing the type of ion crystal (M
R Green et al.: J Phys, D: Appl.
Phys, 131980, intermediate use, etc.: Proceedings of the 2nd Annual Conference of the Laser Society of Japan, 1988, P3B, etc.).

However, in the previously proposed lasers, it is necessary to disassemble the laser in order to replace the crystal, and this merely shows the experimental possibility. No practical device has been proposed that can extract laser light of one wavelength.

SUMMARY OF THE INVENTION The present invention provides a gas laser whose oscillation wavelength can be switched by replacing the crystal with a simple external operation without disassembling the laser.

2.Construction The laser of the present invention is characterized in that a holder to which several types of ion crystals are attached is provided inside the laser, and the holder can be set at an input coupling position by being rotated by an external operation.

Fatsuo side FIG. 1 shows an embodiment of the present invention.

This embodiment is an ammonia gas laser that emits far-infrared oscillation. 1 is a steel pipe, on one end of which a gold-deposited concave mirror 2 with a hole is placed, and on the other end an ion crystal for input coupling is placed. The input ion crystal 3 is attached to a disc holder 4. FIG. 2 shows the front of the holder 4, on which four types of ion crystals 3 are attached. Holder 4
is rotatably mounted within the crystal exchange chamber 5 attached to the end of the copper tube 1, and its shaft extends outside the crystal exchange chamber and is connected to the shaft of a driving stepping motor 6. The excitation infrared light is made to enter through a window 7 provided in the crystal exchange chamber 5. By rotating the stepping motor 6, any one of the four types of ion crystals attached to the holder 4 can be positioned at the end of the copper tube 1. A gas supply port 8 is provided in the crystal exchange chamber 5, and the entire interior of the laser is filled with ammonia gas from the chamber to the inside of the copper tube. The pressure of this ammonia gas is several To
rr to several tens of TOrr, so in order to prevent air from entering from outside, the portion where the axis of the holder 4 penetrates the wall of the crystal exchange chamber 5, the connection between the chamber and the copper tube 1, and the window 7 , between the laser beam extraction chamber 9 and the window 10 on one end side of the copper tube 1, and at the connection between the chamber and the copper tube 1, etc., all must be airtight.

The excitation infrared light enters the laser through the window 7, passes through the crystal 3 located at the input coupling position, and enters the copper tube 1. At this time,
Since the crystal 3 is transparent to the incident excitation infrared rays (wavelength shorter than the laser oscillation wavelength), it can enter the copper tube 1 and excite the ammonia gas inside.0 From the excited ammonia gas molecules Of the far-infrared light of various wavelengths that is emitted, the crystal 3 has a high reflectance for the light of that wavelength, so the light of that wavelength is reflected between the reflecting mirror 2 and the crystal 3.
The laser beam is reflected and reciprocated between the mirrors 2 and 2, and is intensified during that time to become a laser beam that is emitted to the right through the center hole of the reflecting mirror 2.

The relationship between the type of input coupling ionic crystal and the resulting laser oscillation wavelength will be illustrated in the above embodiment. A CO2 gas laser is used as a light source for excitation infrared light.

Set the CO2 gas laser at 10F (32) and excite the ammonia gas. At this time, there are three possible transitions of ammonia gas as shown in FIG. 3A. When KREI-5 is used as the input coupling ionic crystal, the far-infrared high reflection wavelength range of this crystal is 152
There is only a transition that emits a wavelength of .mu.m, and therefore a laser beam of 152 .mu.m is obtained. He also chose koi as another crystal,
When the C02 laser is set to 9R (16) and excited,
When excited by this light, the two types of transition of ammonia gas shown in Figure 3B are possible, but since the crystal of K-4 exhibits a high reflectance at 90-4 μm, the transition at 90.4 μm is possible.
of laser light can be obtained.

Effects Gas lasers are structurally a gas chamber sealed from the outside air, but in the present invention, multiple types of input coupling crystals are held in a holder rotatably installed inside this gas chamber, and external operation is possible. Since the input coupling crystal can be replaced by rotating the holder, the laser can be replaced without disassembling the laser.
Laser oscillation can be performed by selecting any one of a plurality of possible wavelengths, making wavelength switching extremely easy.

[Brief explanation of the drawing]

FIG. 1 is a vertical side view of a gas laser according to an embodiment of the present invention;
FIG. 2 is a front view of the crystal holder in the same example, and FIGS. 3A and 3B are graphs showing possible types of transitions in excited ammonia molecules. DESCRIPTION OF SYMBOLS 1... Copper tube, 2... Concave reflecting mirror, 3... Ion crystal for input coupling, 4... Holder, 5... Crystal exchange chamber,
6...Stepping motor for holder drive, 7...Window, 8...Gas supply port, 9...Laser light extraction chamber, 1
0...window. Representative Patent Attorney Hiroshi Agata (A) (B)

Claims (1)

[Claims] Multiple types of crystals are attached to a rotating holder, each exhibiting a high reflectance only within a bandwidth that includes multiple types of wavelengths corresponding to multiple types of possible transitions from the excited state of the filled gas. , this holder is rotatably installed in a chamber that communicates with the laser oscillation tube and is cut off from the outside air, and by rotating the holder, any one of the plurality of crystals on the holder is moved to the tube end position of the laser oscillation tube. A gas laser made to obtain.