JP2738007B2 - Dye laser - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a dye laser, and more particularly to a dye laser having improved oscillation efficiency and lifetime.

[Prior Art] A dye laser emits laser light by inducing the emission of fluorescence of a fluorescent dye, and FIG. 3 is a configuration diagram of a general dye laser. In the figure, (1) is a dye laser element,
(2) is a light source for excitation, (3) is a total reflection mirror, and (4) is a half mirror. That is, the dye laser element includes a solid type in which a fluorescent dye is dispersed in a transparent resin and a liquid type in which a dye solution dissolved in an appropriate organic solvent is placed in a transparent cell.
When the output power is large, the photobleaching of the dye proceeds, so that the solid type cannot be obtained. In the case of the liquid type, the dye solution is circulated between the external tank (reservoir) and the cell in order to renew the dye solution. In the case of the liquid type, the fluorescence intensity (fluorescence yield) of the fluorescent dye depends on the dye concentration and the type of solvent. When the dye concentration is high or the affinity with the solvent is low, two molecules of the fluorescent dye associate (dimerize) and become non-fluorescent, or the excited molecules of the fluorescent dye do not excite the emitted fluorescence. It happens because the molecule reabsorbs. Also, the fluorescent dye undergoes photobleaching by the following elementary reaction.

Here, S is an unexcited molecule of a fluorescent dye, ¹ S is a singlet excited molecule, ³ S is a triplet excited molecule, ³ O ₂ is a triplet oxygen (unexcited molecule), and ¹ O ₂ is a singlet excited oxygen molecule. , Hν represents irradiation light, hν ′ represents fluorescence, and k represents a reaction rate constant.

 The fade rate (R) is derived from these equations.

As the solvent for the liquid dye laser, an organic solvent such as alcohol and toluene and water are used. When the dye solution is circulated, a large amount of the dye solution is stored in the external tank. Therefore, it is preferable to use water that is harmless to the human body and has no fear of fire or the like as the solvent. When a fluorescent dye molecule having a relatively low polarity is dissolved in water having a strong polarity, the dye molecule often dimerizes and the fluorescence yield is often significantly reduced. As a result, when laser oscillation is performed using such an aqueous dye solution, the output is significantly reduced, and in an extreme case, oscillation is stopped. Also, fluorescent dye molecules generally have poor photostability,
When the photoexcitation is performed by the excitation light source, the photobleaching is performed in accordance with the aforementioned fading speed equation.

Therefore, for example, the publication ｛CHEMICAL PHYSICS LETTERS
As shown in Vol.104 No.5 p.496-499｝, we tried to prevent fluorescent dye dimerization by using an inclusion compound in which a fluorescent dye was included with cyclodextrin for the dye laser. did.

[Problems to be Solved by the Invention] However, when the above-mentioned inclusion compound is used for a dye laser, there are some dyes that are not well included with cyclodextrin due to the inclusion mechanism, and some dyes that are not well included with cyclodextrin. There is a limit to the pigment. In addition, the amount of cyclodextrin required for practical use as a dye laser is large and the cost is high. Further, the above publication states that the luminous efficiency of the dye laser is increased, but there is a problem that the fading of the fluorescent dye is not mentioned.

The present invention has been made in order to solve such a problem, and even when water is used as a solvent, it is possible to more efficiently prevent dimerization of a wider range of fluorescent dye molecules and reduce the output of laser oscillation. It is an object of the present invention to obtain a dye laser having a long life by preventing and preventing photobleaching of fluorescent dye molecules.

[Means for Solving the Problems] A dye laser according to the present invention includes a dye laser element containing a fluorescent dye, and an excitation light source that stimulates emission of the fluorescent dye of the dye laser element to cause laser oscillation. Wherein the dye laser element is formed of a water-containing solution of an inclusion compound in which the fluorescent dye is included with at least one of a nucleic acid derivative having a cholate and a purine base. It is assumed that.

[Action] In the present invention, since one fluorescent dye molecule is included in the solution and is included in the solution, a decrease in fluorescence yield due to dimerization is suppressed. In order to protect the active points of the dye molecules, the photobleaching speed is greatly reduced, the oscillation output of the dye laser is stabilized, the decrease with time is greatly improved, and the life is extended. When a fluorescent dye is included with at least one of a nucleic acid derivative having a cholate and a purine base, unlike a conventional cyclodextrin, the dye is included in a sandwich form, so that the fluorescent dye is included regardless of the size of the dye molecule. A wide range of dyes can be contacted. Furthermore, the equilibrium constant for obtaining an inclusion compound is high, the use of a nucleic acid derivative having a cholate and a purine base can be used in a small amount, and the cost can be reduced.

Examples The fluorescent dyes according to the present invention include, for example, xanthene fluorescent dyes such as rhodamine 6G, rhodamine B, fluorescein, calcein blue, eosin and erythrosine, diethylaminomethyl coumarin and 4-
Coumarin-based fluorescent dyes such as methylumbelliferone and acridine-based fluorescent dyes such as acridine red are used.

As the cholate of the compound that includes the fluorescent dye according to the present invention, for example, sodium deoxycholate is used.

Examples of the nucleic acid derivative having a purine base of the compound that includes the fluorescent dye according to the present invention include caffeine, adenosine-5-monophosphate, and guanosine-5'-.
Monophosphate, inosine-5'-monophosphate, polyadenylic acid, polyinosinic acid, adenylyl-(-3'-5 ') cytidine, adenyl-(-2'-5') cytidine, polyadenylic acid, polyguanylic acid, polyinosin Acids, deoxyribonucleic acids, ribonucleic acids and the like are used.

The fluorescence intensity and the photobleaching rate of a water-containing solution of the clathrate compound according to the present invention were measured. That is, the fluorescence intensity and the photobleaching speed when a compound to be included was added to the fluorescent dye were measured, and the effect of the addition was confirmed. Rhodamine 6G, which is a typical dye for laser, was used, and water which was harmless to humans and free from fire or the like was used as a solvent. An aqueous solution having a concentration of 1 × 10 ⁻³ mol / l was prepared, and sodium deoxycholate and caffeine according to the present invention and α-cyclodextrin used in a conventional dye laser were added to 1 × 10 ⁻³ to 1 × 10 ⁻³ mol / l. An aqueous solution added in the range of × 10-1 mol / l was prepared. The fluorescence intensity of the aqueous solution to which the inclusion compound was not added was defined as _Io , the fluorescence intensity I of the aqueous solution added at each concentration was measured, and the relative fluorescence intensity ( _Io / I) was calculated. The results are shown in FIG. Show. FIG. 1 is a characteristic diagram showing a change in relative fluorescence intensity (I _o / I) depending on the addition concentration (mol / l) of the compound to be included, in which the vertical axis represents the relative fluorescence intensity and the horizontal axis represents the compound of the inclusion compound. The addition concentration, ◎ indicates sodium deoxycholate, □ indicates caffeine, and ★ indicates α-cyclodextrin. As is clear from FIG. 1, the relative fluorescence intensity is increased by adding the inclusion compound, and the improvement of the laser oscillation efficiency can be expected. The reason that the relative fluorescence intensity increases is that, in an aqueous solution, rhodamine 6G has a fluorescence intensity of about 1/6 that in the case of using methyl alcohol as a solvent because a non-fluorescent dimer in which two molecules are associated is more stable. But rhodamine 6
Inclusion of G one molecule at a time increases I _o / I up to about 6-fold. It is considered that the effect of adding α-cyclodextrin, which has been conventionally used in the dye laser, is lower than that of the others because the pore size in the molecule and the molecular size of rhodamine 6G do not match.

Next, an aqueous solution of the rhodamine 6G (concentration 1 × 10 ⁻⁵ mol /
In l), an aqueous solution to which sodium deoxycholate and caffeine according to the present invention were added was prepared, and the photobleaching speed upon irradiation with a xenon lamp was measured. the rate and R _o, measured photobleaching rate R of the aqueous solution were added at each concentration,
The specific photofading speed (R _o / R) was calculated, and the results are shown in FIG. FIG. 2 is a characteristic diagram showing a change in specific photobleaching speed (R _o / R) depending on the addition concentration (mol / l) of the compound to be included. In the figure, the vertical axis indicates the specific photobleaching speed, and the horizontal axis indicates inclusion. Compound addition concentration, 添加 indicates sodium deoxycholate, □ indicates caffeine. As is clear from FIG. 2, the specific photobleaching speed is reduced to about 0.2, that is, the photobleaching speed is reduced to about 1/5 by adding the inclusion compound, and it is expected that the life of the dye laser is prolonged.

 Hereinafter, the present invention will be described specifically with reference to examples.

Example 1 Rhodamine 6G at a concentration of 10 ⁻³ mol / l and caffeine at a concentration of 20
It is dissolved in water so as to have a concentration of × 10 ^-3 mol / l, and is attached to the dye laser shown in FIG. When excited by a 5w excitation light source, the output is 1.
It was 1w. This oscillation maintained 80% output even after 10 minutes.

Comparative Example 1 The same operation as in Example 1 was carried out except that caffeine was not added, and the output was as low as 0.2 w.

Comparative Example 2 Rhodamine 6G having the same concentration as in Example 1 was dissolved in ethyl alcohol, mounted on the dye laser shown in FIG. 3, and oscillated in the same manner as in Example 1. w. But after about 10 minutes this output
It has fallen below 40%.

Example 2 DCM ｛4-Dicyanomethylene-2-methyl-6- (p-dimethy
laminostyryl) -4M-pyran｝ is dissolved in 100 ml of dimethyl sulfoxide to a concentration of 10 ⁻³ mol / l and sodium deoxycholate to a concentration of 30 × 10 ⁻³ mol / l, and the solvent is evaporated by a rotary evaporator. The residue was dissolved in 100 ml of distilled water, mounted on the dye laser shown in FIG. 3, and excited with a 5 w argon laser to obtain a 2 w output. This output was 80% after 90 minutes.

In the above example, the case where 100% of water is used as the solvent is shown, but the intended purpose can be achieved even when about 50% of water is used.

[Effects of the Invention] As described above, the present invention relates to a dye laser element containing a fluorescent dye, and an excitation light source that stimulates emission of fluorescence of the fluorescent dye of the dye laser element to cause laser oscillation. Wherein the dye laser element is formed of a water-containing solution of an inclusion compound in which the fluorescent dye is included with at least one of a nucleic acid derivative having a cholate and a purine base. By using water, even when water is used as a solvent, a wider range of fluorescent dye molecules can be more sensitively prevented from dimerizing, preventing a decrease in laser oscillation output, and furthermore, photobleaching of fluorescent dye molecules. , It is possible to obtain a dye laser having a longer life.

[Brief description of the drawings]

FIG. 1 shows the relative fluorescence intensity (I _o / I) depending on the addition concentration (mol / l) of the clathrate compound comparing the embodiment of the present invention with the conventional example.
FIG. 2 is a characteristic diagram showing a change in specific photobleaching rate (R _o / R) depending on the addition concentration (mol / l) of an inclusion compound comparing the embodiment of the present invention with a conventional example. FIG. 3 is a block diagram of a general dye laser. In the figure, ◎ indicates sodium deoxycholate, and □ indicates caffeine.

Claims (1)

(57) [Claims] 1. A dye laser device containing a fluorescent dye, and an excitation light source that stimulates emission of fluorescence of the fluorescent dye of the dye laser device to cause laser oscillation. A dye laser comprising a fluorescent dye formed from a water-containing solution of an inclusion compound in which at least one of a nucleic acid derivative having a cholate and a purine base is included.