JPH09275235A - Dye laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laser beam which is kept stable in wavelength and spectral characteristics for a lung term by a method wherein a guide longer than the diameter of the condensed ray spot of exciting laser rays is provided to both the lengthwise ends of an opening of a jet nozzle so as to surround the side of a dye jet. SOLUTION: A jet nozzle 24 is possessed of an exhaust nozzle which is formed like a slit in cross section and provided with a guide 24a which is longer than the diameter of the condensed ray spot of exciting laser rays 2 and located at both the lengthwise ends of the exhaust nozzle in a front view so as to surround the side of a dye jet 17. The exciting laser rays 2 are so constituted as to irradiate a dye jet stream 17 jetted out from the jet nozzle 24 between the guides 24a. A dye solution is circulated by a circulating pump, bubbles and impurities contained in the dye solution are removed with a filter, and a flow of die solution can be kept stable by an accumulator and jetted out as a dye jet 17 at a speed of 10m/s or so.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dye laser device in which continuous wave laser light is used as an excitation light source and laser output is continuously oscillated. In particular, the present invention relates to a dye laser device in which the stability of wavelength (frequency) and spectrum shape of a laser beam is improved.

[0002]

2. Description of the Related Art A dye laser device is a device which excites a solution of an organic dye with laser light for excitation and utilizes fluorescence emitted at that time. The oscillation wavelength range differs depending on the type of medium, covering a wide wavelength range from near ultraviolet to near infrared, and by providing an appropriate wavelength selection element in the optical path, a dye laser with a specific wavelength can be obtained. it can.

FIG. 12 shows a conventional ring type dye laser device disclosed in, for example, Japanese Patent Application Laid-Open No. 3-183184. In the figure, 1 is an argon ion laser that emits coherent continuous light for excitation laser light, 2 is excitation laser light emitted from the argon ion laser 1, 3 is a total reflection mirror, and 4 is a jet of dye solution at high speed. Dye jet 5, 5 is a dye circulator that circulates the dye solution to obtain dye jet 4, 6, 7 and 8 are reflectors, 9
Is an output mirror, 10 is a dye laser beam obtained by oscillation, 11 is an isolator, and 12 is laser output light.

An example of a simple structure of the above-mentioned dye circulator 5 is disclosed in, for example, Japanese Patent Laid-Open No. 3-238889. FIG. 13 is a configuration diagram of a dye circulator in the dye laser transmitting device disclosed in that publication. In the figure, 13
Is a circulation pump for circulating the dye solution, 14 is a pipe line, 15 is a jet nozzle for producing the dye jet 4, and 16 is a catcher.

Next, the operation will be described. The excitation laser light 2 output from the argon ion laser 1 is reflected by the total reflection mirror 3 and is applied to the dye jet 4.
The dye of the dye jet 4 irradiated with the excitation laser light 2 is excited and emits fluorescence. The generated fluorescence is reflected by the mirror 6,
7 and 8 and the output mirror 9 resonate in an optical path formed in a figure 8 shape, and output as output light from the output mirror 9. The isolator 11 restricts the laser light transmission direction to only one direction on the output side.

Here, in the dye circulation section, as shown in FIG. 13, the dye solution is sent to the pipe line 14 by the circulation pump 13 and jetted from the jet nozzle 15 as a thin flat plate-shaped dye jet 4 to the catcher. It is collected in 16 and returned to the circulation pump 13 again. The excitation laser light 2 is
It is configured to irradiate the flat surface of the dye jet 4. At this time, it is necessary that the thickness of the jetted dye solution is uniform, and the jet nozzle 15 is widely adopted, for example, in which a slit-shaped opening is formed by flatly pressing the tip of a thin metal tube. Has been done.

In the dye laser device, keeping the flow velocity of the dye jet 4 constant and keeping the thickness uniform are very important factors for obtaining a good quality laser output light 12.

[0008]

Since the conventional dye laser device is configured as described above, the dye jet ejected from the jet nozzle is easily affected by the surrounding air layer. A slight turbulence in the air layer may cause fluctuations (turbulence in the flow) on the jet surface, which may cause variations in thickness or irregularities on the flat surface, so that a jet surface of a dye jet that is stable and has little fluctuation for a long time can be obtained. It was difficult. For this reason, the wavelength (frequency) and spectrum shape of the dye laser light become unstable, and there is a problem that stable operation cannot be performed for a long time.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a dye laser device for obtaining laser light having a stable wavelength (frequency) and spectrum shape for a long time. .

[0010]

SUMMARY OF THE INVENTION A dye laser device according to the present invention jets a dye solution into a thin flat plate dye jet from the tip of a jet nozzle, and irradiates a flat plate surface of the dye jet with laser light for excitation. In a dye laser device that obtains dye laser light of a predetermined wavelength, at least both ends of the opening of the jet nozzle in the width direction are surrounded by the side surface of the dye jet and have a length at least equal to or larger than the focusing diameter of the excitation laser light. A guide part is provided.

Further, bulges are formed at both ends of the opening at the tip of the jet nozzle in the width direction, and the excitation laser light is irradiated onto the flat plate surface excluding the bulges at both ends of the jetted dye jet. is there.

Further, an injection port for injecting an air jet having substantially the same velocity as the dye jet is provided at least on the wide side around the opening of the jet nozzle so as to cover the jet surface of the dye jet.

Furthermore, the tip of the jet nozzle is made of a material having high wear resistance.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a ring type dye laser device according to the first embodiment. 2 is a block diagram of the dye circulator therein, FIG. 3 is a front view of the jet nozzle, and FIG. 4 is IV- of FIG.
It is an expanded sectional view seen from IV. In FIG. 1, 1 is an argon ion laser that emits coherent continuous light for excitation laser light, 2 is excitation laser light output from the argon ion laser 1, 3 is a total reflection mirror, 1
7 is a dye jet in which a dye solution 19 described later is jetted at high speed, 18 is a dye circulator that circulates the dye solution 19 to obtain the dye jet 17, and 6, 7 and 8 are reflecting mirrors.
Reference numeral 9 is an output mirror, 10 is a dye laser light obtained by oscillation, 11 is an isolator for controlling the direction of the laser light in one direction, and 12 is laser output light.

In FIG. 2, 19 is a dye solution,
For example, an appropriate amount of a predetermined dye such as Rhodamine 6G is dissolved in a solvent having good adhesiveness such as ethylene glycol. Reference numeral 20 is a pipe line, 21 is a circulation pump for circulating the dye solution 19, 22 is a filter, 23 is an accumulator (pulsating smoother), 24 is a jet nozzle for producing the dye jet 17, 25 is a catcher for collecting the dye jet 17, 26 is a reservoir tank for storing the dye solution 19,
Reference numeral 27 is a bypass valve for adjusting the pressure. The dye circulator 18 is composed of 20 to 27.

As shown in FIGS. 3 and 4, the jet nozzle 24 has a jet-shaped cross section at the jetting portion, and the side surface of the dye jet 17 is provided at both ends in the wide width direction when viewed from the front of the tip side. A guide portion 24a having a length at least equal to or larger than the focused diameter of the excitation laser light 2 is provided so as to surround it. The excitation laser beam 2 is configured to irradiate the jet surface of the dye jet jet 17 jetted from between the guide portions 24a.

Next, the operation will be described. The excitation laser beam 2 output from the argon ion laser 1 is reflected by the total reflection mirror 3 and is applied to the dye jet 17. The dye jet 17 is a thin flat plate-like dye flow for supplying the dye to the laser excitation region.
4 to produce the dye solution 19 at high speed. The dye in the dye jet 17 irradiated with the excitation laser light 2 is excited and emits fluorescence. The generated fluorescence is reflected by mirrors 6, 7,
The optical path formed by the 8 and the output mirror 9 in the shape of a figure 8 goes around once and returns to the same point. When the optical path length of one round matches an integral multiple of the oscillation frequency, the laser light resonates in the same phase when returning, and the wavelength-selected dye laser light 10 is oscillated. The oscillated dye laser light 10 passes through the output mirror 9 and is output as laser output light 12. The isolator 11 interposed in the 8-shaped optical path regulates the fluorescence transmission direction in only one direction on the output side, and the laser emission light is coupled with the original laser light by reflection from an external circuit. Prevent.

Next, the dye circulator 18 will be described.
As shown in FIG. 2, the dye solution 19 is constantly circulated by the circulation pump 21. In the circulation process, bubbles and impurities in the dye solution 19 are removed by the filter 22, a stable flow is created by the accumulator 23, and the jet nozzle 24 puts it in the air, for example, at 10 m / s.
At a flow velocity of about a certain level or more, the thin flat plate-shaped dye jet 17 is ejected. A predetermined dye laser light 10 is excited by irradiating the jet laser surface 2 with the appropriately narrowed excitation laser light 2. Dye solution 1 sprayed in the air
9 is collected by the catcher 25, sent back to the reservoir tank 26, and circulated again in the circulator system by the circulation pump 21.

In general, the velocity of the jet flowing out of the stationary fluid from the nozzle is uniform in the central portion of the jet immediately after it exits the nozzle. This constant velocity portion becomes smaller due to the free mixing layer developing from both sides and disappears at a certain distance from the nozzle.

Therefore, the guide portions 24a provided at both ends of the jet nozzle 24 in the width direction act as follows. The portion 2 of the jet nozzle 24 where there is no guide in the central portion in the width direction
4b, even if the dye solution 19 is separated from the tip of the jet nozzle 24, a free mixing layer with the atmosphere is not generated on the side surface of the jet flow while the guide portions 24a are provided on both sides of the thin plate-shaped dye jet 17, and the central portion The flow velocity is kept almost uniform. That is, since the guide portion 24a is provided, the distance of the portion at a constant speed in the central portion is extended, and since disturbances from both sides do not enter, jet turbulence is small and fluctuations in jet thickness are stable. The jet surface can be obtained.

Further, in general, the size of the tip opening portion of the jet nozzle of such a dye laser device is, for example, about 5 mm × 0.5 mm or less in cross section, and in the case of a small one, it is on the order of micron, so the dye between the guides 24a, 24a. Interfacial tension acts on the surface of the jet 17, and the surface is pulled by the guides 24a, 24a by this force to form a smooth jet surface. Therefore, if the excitation laser light 2 is focused on the jet surface between the guide portions 24a, 24a where the velocity fluctuation is small and the surface is smooth, the wavelength (frequency) and the spectral shape of the dye laser light are long. It is possible to obtain a dye laser device which is stable over time.

In the above description, the guide portion 2
Although it has been described that 4a is added to the tip of the jet nozzle, when actually manufacturing the jet nozzle, for example,
As shown in FIG. 3 shown in the present embodiment, the distal end of the thin tube may be pressed to form a slit-like opening, and the end may be cut into a U-shape. In this case, the shape of the cut portion may not be a U-shape, but may be a semicircle, for example. Further, instead of processing from a thin tube, it is also possible to combine the plate materials or process and form the nozzle openings by a fine processing technique.

Embodiment 2 FIG. 5 is a front view of the jet nozzle portion according to the second embodiment, and FIG. 6 is an enlarged cross-sectional view taken along the line VI-VI of FIG. The configuration and the operation of the dye laser device other than the jet nozzle portion are the same as those shown in FIGS.
In the figure, reference numeral 28 denotes a jet nozzle, which is a guide portion having a length at least equal to or larger than the diameter of the excitation laser beam 2 so as to surround the side surface of the dye jet 29 at both ends in the width direction when viewed from the front side. 28a is provided. Then, bulged portions 28b are formed at both ends in the width direction of the opening at the tip. That is, as shown in FIG. 6, bulged portions 28b having a circular shape with a diameter larger than the slit thickness are formed at both ends of the parallel slit portions 28c. The excitation laser beam 2 irradiates the jet surface of the dye jet 29 on the extension surface of the parallel slit portions 28c in the jet direction except for the bulged portions 28b at both ends.

The operation will be described below. The guide portion 28a of the jet nozzle 28 has the same function as the guide portion 24a of the jet nozzle 24 of FIG. 3 described in the first embodiment. That is, the formation of a free-mixing layer with the atmosphere on the side surface of the jet is prevented, the flow velocity in the central portion of the thin plate-shaped dye jet 29 is kept substantially uniform, and further, both guide portions 28a, 2 are provided.
Interfacial tension acts on the jet surface of the dye jet 29 between 8a, and this force pulls the surface toward both guide sides to make it smooth.

Next, the operation of the bulged portions 28b at both ends will be described. Generally, when a fluid is flowed through a pipe with a rectangular cross section, the velocity of a flat part with a certain width from the center in the wide direction is almost uniform, but the velocity decreases significantly as it approaches the corners on both sides. To do. In addition, a flow component (secondary flow) in a direction perpendicular to the flow in the pipe appears in the corner portion, and the friction coefficient increases.

Therefore, by providing the bulged portions 28b having a large cross-sectional area at both ends in the width direction of the jet nozzle 28, it is possible to prevent a decrease in the flow velocity at both ends and to reduce the secondary flow. , The degree of turbulence becomes small. For this reason, in the width direction of the dye jet 29, a range of uniform velocity and less turbulence spreads.

Further, the jet stream jetted from the bulge portion 28b serves to reinforce the jet surface in the central portion and reduces the degree to which the atmosphere is mixed from the side surface and disturbs the flow.

Although the bulge portion 28b has an arc-shaped cross section, the same effect can be obtained even if the bulge portion 28b is not arc-shaped, for example, elliptical or rectangular.

Embodiment 3 7 is a front view of the jet nozzle portion of the dye laser device according to the third embodiment, and FIG. 8 is an enlarged cross-sectional view taken along line VIII-VIII of FIG. The configuration and operation of the dye laser device other than the jet nozzle portion are the same as those shown in FIGS. 1 and 2 shown in the first embodiment, and therefore description thereof is omitted. In the figure, reference numeral 30 is a jet nozzle, and the tip portion has guide portions 30a at both ends similarly to FIG. 5 shown in the second embodiment, and the cross section of the opening has circular bulge portions at both ends of the parallel slit portion. It is provided.
An air guide 31 is provided on the outer periphery of the jet nozzle 30 with a minute gap, and is a guide portion 30 of the jet nozzle 30.
A guide portion 31a is provided so as to cover it according to a. 32 is a nozzle holder that holds the jet nozzle 30 and the air guide 31, 33 is an air intake port, 34 is an air jet port, 35 is a pigment jet, and 36 is an jet port 34.
The outer surface of the dye jet 35 jetted from the dye jet 3
It is an air jet that flows at almost the same speed as 5.

Next, the operation will be described. As described in the second embodiment, the jet nozzle 30 can obtain a stable dye jet 35 with little fluctuation in the vicinity of the central portion, and further, the jet velocity of the dye jet 35 from the ejection port 34 to the periphery of the dye jet 35. Since the air jet 36 is jetted at a speed substantially equal to, the frictional resistance between the outer surface of the dye jet 35 and the air surrounding the outer surface thereof is significantly reduced, and the fluctuation of the surface of the dye jet 35 is significantly reduced.

Here, assuming that the temperature of the air jet 36 is a constant temperature close to the temperature of the dye jet 35, the dye jet 3
Since the temperature of 5 can be kept constant, a dye jet with less fluctuation can be obtained.

The air jet 36 is the dye jet 3
Although the case of jetting from the entire circumference of No. 5 was described, the effect of the surrounding air layer on the jet surface is larger on the wide surface of the dye jet, so it is expected to be effective if it is jetted from at least the wide surface of the dye jet. it can. Further, even if the jet nozzle is formed into a shape as shown in FIGS. 3 and 4 in which the bulge portion is not provided, the effect of the air jet can be expected.

Fourth Embodiment 9 is a front view showing a partial cross section of a jet nozzle portion of a dye laser device according to a fourth embodiment, FIG. 10 is a side cross sectional view of FIG. 9, and FIG. 11 is of FIG.
It is an expanded sectional view seen from XI-XI. The configuration of the dye laser device other than the jet nozzle portion is the same as that shown in FIGS. 1 and 2 shown in the first embodiment, and therefore its explanation is omitted. In the figure, 37 is a main nozzle, 38 is a tip nozzle made of a hard material with high abrasion resistance such as diamond or sapphire, and the jet part has a slit-shaped cross section.
Circular bulges 38b having a diameter larger than at least the slit thickness are provided at both ends in the width direction. Reference numeral 39 denotes a guide nozzle provided so as to surround the wide side surface of the dye jet 40. The guide nozzle 39 serves as a guide portion for the dye jet 40 and also serves to fix the tip nozzle 38 to the tip of the main body nozzle 37. Reference numeral 41 denotes an air ejection port provided in the main body nozzle 37 corresponding to the wide surface of the tip nozzle 38, and the air jet 42 is provided so as to cover the wide side of the dye jet 40.
Inject. Reference numeral 43 is an air conduit for supplying air from an air supply device (not shown).

Next, the operation will be described. The dye solution sent from the dye circulator passes through the inside of the main body nozzle 37 and is vigorously ejected from the tip nozzle 38 as the dye jet 40. At this time, the guide nozzles 39 provided on both sides of the wide surface of the slit of the tip nozzle 38 prevent the atmospheric layer from entering from the side surface of the jet flow, so that the flow velocity in the central portion of the jet flow is kept substantially constant. There is.

Further, when the jet width of the dye jet 40 is small, the interfacial tension acts on the jet surface between the guides 39, 39, and this force pulls the jet film toward both guide sides, so that the jet surface is It becomes smoother.

Further, since the bulge portions 38b are provided at both ends of the slit of the opening of the tip nozzle 38, as described in the second embodiment, the flow velocity is reduced at both ends of the tip nozzle 38 in the wide width direction of the opening. In addition, since the secondary flow is reduced and the degree of turbulent flow is reduced, the velocity of the central portion of the dye jet 40 in the width direction is uniform and the range in which there is little turbulence is widened.

Further, the jet flow jetted from the bulge portion 38b serves to reinforce the jet face in the central portion, and reduces the degree to which the air is mixed from the side face to disturb the flow.

Further, the air jet 42 jetted from the jet port 41 of the air remarkably reduces the frictional resistance between the outer surface of the dye jet 40 and the air layer similarly to the air jet described in the third embodiment.

Furthermore, the velocity of the dye jet is generally 1
Since it is 0 m / s or more, if it is used for a long time, the inner surface of the opening of the jet nozzle may be worn or damaged,
The jet thickness may change, or the smoothness of the jet surface may be impaired. In the dye laser device, this slight change in the jet surface greatly affects the quality of laser light. Therefore, since the tip nozzle 38 shown in the present embodiment is made of a hard material having high abrasion resistance, the inner surface of the opening of the nozzle is less likely to be worn or scratched even when used for a long time. , The impaired thickness and surface smoothness of the dye jet is greatly reduced.

The bulge portion 38b and the air jet 4
Even if either or both of the injection ports 41 for ejecting 2 are not provided, the above-mentioned effect can be expected because the tip nozzle 38 is made of a hard material having high abrasion resistance.

Further, in the first to fourth embodiments, the ring type dye laser device has been described, but a standing wave type dye laser device can also obtain the same effect. Also,
The dye circulator has a general circulation path structure as shown in FIG. 2, but the structure is not limited to that shown in FIG. 2, and it is sufficient if the dye solution can be circulated at a constant speed without pulsating flow.

[0042]

As described above, according to the first aspect of the invention, since the guide portions are provided at both ends of the jet nozzle tip in the wide direction, the fluctuation of the dye jet jet surface is improved and the variation of jet thickness is suppressed. A small and stable jet surface can be obtained, and a dye laser device in which the wavelength (frequency) and spectrum shape of the dye laser light are stable for a long time can be obtained.

Further, according to the second aspect of the invention, since the bulged portions having a large cross-sectional area are provided at both ends in the wide width direction of the tip of the jet nozzle, the portion where the velocity of the dye jet in the width direction is uniform is increased to cause disturbance. A jet surface with little flow can be obtained.

Further, according to the third aspect of the invention, since the air jet having the same velocity as the dye jet is jetted so as to cover the jet surface of the dye jet, the fluctuation of the surface of the jet of jet is greatly reduced. .

Furthermore, according to the fourth aspect of the invention, since the tip of the jet nozzle is made of a material having high abrasion resistance, it is possible to obtain a stable jet surface of the dye jet for a long time.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a dye laser device according to a first embodiment.

FIG. 2 is a configuration diagram of a dye circulator of the dye laser device of FIG.

FIG. 3 is a front view of a jet nozzle of the dye laser device of FIG.

FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG.

FIG. 5 is a front view of a jet nozzle of a dye laser device according to a second embodiment.

6 is an enlarged cross-sectional view taken along the line VI-VI of FIG.

FIG. 7 is a front view of a jet nozzle of a dye laser device according to a third embodiment.

FIG. 8 is an enlarged cross-sectional view taken along the line VIII-VIII of FIG. 7.

FIG. 9 is a front view showing a partial cross section of a jet nozzle of a dye laser device according to a fourth embodiment.

FIG. 10 is a side sectional view of FIG.

FIG. 11 is an enlarged cross-sectional view seen from XI-XI in FIG. 9.

FIG. 12 is a configuration diagram of a conventional dye laser device.

FIG. 13 is a configuration diagram of a dye circulator of a conventional dye laser device.

[Explanation of symbols]

2 Laser light for excitation 10 Dye laser light 17, 29, 35, 40 Dye jet 19 Dye solution 24, 28, 30 Jet nozzle 24a, 2
8a, 30a guide part 28b, 38b bulge part 34, 41
Injection port 36,42 Air jet 37 Main body nozzle 38 Tip nozzle 39 Guide nozzle

Claims (4)

[Claims] 1. A dye laser in which a dye solution is jetted from a tip of a jet nozzle into a thin flat plate-shaped dye jet, and the flat plate surface of the dye jet is irradiated with excitation laser light to obtain a dye laser light of a predetermined wavelength. In the device, at both ends of the opening of the jet nozzle in the wide direction, a guide portion having a length of at least the focused diameter of the excitation laser light is provided so as to surround the side surface of the dye jet. Dye laser device. 2. The dye laser device according to claim 1, wherein
It is characterized in that bulges are formed at both ends in the width direction of the opening at the tip of the jet nozzle, and the excitation laser light is irradiated onto the flat plate surface excluding the bulges at both ends of the jetted dye jet. Dye laser device. 3. The dye laser device according to claim 1, wherein air having substantially the same velocity as the dye jet is provided on at least a wide side around the opening of the jet nozzle so as to cover the jet surface of the dye jet. A dye laser device having an injection port for ejecting a jet. 4. The dye laser device according to any one of claims 1 to 3, wherein the tip of the jet nozzle is made of a material having high abrasion resistance.