JPH022190A - Laser device - Google Patents

Abstract

PURPOSE:To emit a plurality of laser lights by one unit of laser device by laminating a plurality of elliptic tube whose inner surface is an excitation light reflecting surface so that one focal line of each tube is common to form a laminated elliptic tube, by arranging an excitation light source on the common focal line of the laser head and by arranging a laser oscillation element on each of the other plurality of focal lines respectively. CONSTITUTION:A laser head 1 is formed in a laminated elliptic tube which is made by joining a curbed plate body divided into four whose inner surface is an excitation light reflecting mirror and by laminating two elliptic tubes 1a, 1b. One focal line 2b of focal lines 2a, 2b, 2b, 2c is made common. A flash lamp 3 of an excitation light source is located on the common focal line 2b and dye cells 4a, 4b of a laser oscillation element to generate a laser light of object wavelength are located on the other two focal lines 2a, 2c. The dye cells 4a, 4b are made by bonding a quartz window plate 9 at the both sides of a transparent quartz tube 8 and an inflow port 10 and an outflow port 11 of dye solution are provided therebetween to circulate the dye solution stored in a dye solution reservoir inside the transparent quartz tube 8 though a circulation pump.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a laser device that can optically excite a plurality of laser oscillation elements with one excitation light source.

"Conventional technology" First, the principle of the dye laser device will be briefly explained.

A dye laser device uses a dye cell obtained by dissolving a dye to a predetermined concentration using a solvent and storing the resulting solution in a container. On the extension line of both ends of this dye cell,
The reflecting mirrors are arranged so that their reflecting surfaces face each other. Then, excitation light generated by an excitation light source is irradiated from the side of the dye cell to cause the dye to emit light. Laser oscillation is caused by multiple reflection between the pair of reflecting mirrors, and a bright line spectrum corresponding to the type of dye is extracted as laser light from one of the reflecting mirrors.

2. Description of the Related Art Conventionally, a dye laser device having a structure as shown in FIGS. 6 and 7 is known as a dye laser device that oscillates when excited by a flash lamp of a xenon lamp type. Here, (1) is a laser head consisting of an elliptical cylinder whose inner surface is a reflecting mirror, and a flash lamp (3) and a dye cell (4) are placed on the two focal lines (2a) and (2b) of this laser head (1), respectively. is located. The reason why the laser head (1) is composed of an elliptical cylindrical reflecting mirror is that light emitted from a point on one focal line (2a) has a property of converging at a point on the other focal line (2b). Specifically, as shown in Figure 7, one focal line (2a)
The excitation light emitted from one point of the flash lamp (3) placed above excites the dye cell (4) placed on the focal line (2b) of the other side.
) with low loss. Therefore, it is useful for improving laser oscillation efficiency. The dye cell (4) is connected to a dye solution reservoir and a dye solution circulation pump (both not shown) prepared outside the laser head (1).
4) A dye solution is allowed to flow inside.

The laser beam is excited by a flash lamp (3), and the fluorescence emitted by the dye in the dye cell (4) undergoes multiple reflections between two reflecting mirrors (5) and (6) placed outside both ends of the dye cell (4). A part of the amplified light passes through a reflecting mirror (6) and is emitted to the outside as a laser beam (7).

In addition, as shown in Fig. 8, there is a laser head (1) that has two elliptical cylinders (la) and (lb) with one focal line (2b) overlapping to form a double elliptical cylinder. A dye cell (4) is installed on the common focal line (2b), and a flash lamp (2) is placed on the other two focal lines (2a) (2c).
3a) By installing (3b) as shown below, the energy injected into each lamp can be halved and the lamp life can be greatly extended.

``Problems to be Solved by the Invention'' However, in any of the above laser devices, only one laser beam is emitted from one dye cell (4).

By the way, one device may require two laser beams with different wavelengths. For example, a cancer diagnostic device using laser pulses already proposed by Mizuide et al.
9464) uses 405 nm laser light pulses, which are used to discover cancer foci, and 630 nm laser light pulses, which are used to treat cancer foci.

More specifically, Hematoporphyrin Deriva, a photosensitizer with high affinity for cancer tissues.
tive (HpD) into the body, and then 405n
When a cancer focus is irradiated with m-laser light, red fluorescence, which is unique to IpD (generated from cancer tissue), is generated. By detecting this, the location of the cancer focus can be found. Next, 630nm laser light is irradiated to the cancerous lesion that has been found)
Excite pD. Then, the IPD is excited and transmits the energy obtained at that time to the oxygen in the cancer lesion to activate the oxygen, and as a result, the active oxygen causes necrosis of the cancer tissue.

Conventionally, when two different wavelengths of laser light, 405 nm and 630 nm, are required, 405 nm and 630 nm, respectively, are required.
Two laser devices are used: nm and 630 nm;
A dye laser device that can oscillate 405r++++ and 630nm, and an ultraviolet laser device necessary to excite it.
Since the type laser device was used, there were problems in that it was expensive and required a large installation space.

An object of the present invention is to obtain a device that can emit a plurality of laser beams using one laser device.

"Means for Solving the Problems" The present invention provides a plurality of elliptical cylinders whose inner surfaces are excitation light reflecting surfaces.
A laser head composed of multiple elliptical cylinders is superimposed so that one focal line of each is common, and an excitation light source is placed on the common focal line, and the excitation light source is placed on the other plural focal lines. Each laser oscillation element is arranged.

"Operation" The excitation light generated by an excitation light source such as a flash lamp excites the pigments that generate laser light of the desired wavelength in each of the multiple laser oscillation elements consisting of dye cells, and the necessary laser light is extracted from these. generate. Since the laser head is a multiple elliptical cylinder whose inner surface serves as an excitation light reflecting mirror, excitation light from the excitation light source is efficiently irradiated onto the laser oscillation element.

"Example" An embodiment of the present invention will be described below based on the drawings.

In FIG. 1, (1) is a laser head.

This laser head (1) is made up of two elliptical cylinders (la) (
It is formed into a multi-elliptic cylinder shaped like a polymerized lb),
Each focal line (2a) (2b), (2b) (2c
), one focal line (2b) is shared. The eccentricities of these two elliptical cylinders (la) (lb) may be the same or different, as long as they have one focal line (2b) in common. A flash lamp (3) as an excitation light source is placed on the common focal line (2b) of the laser head (1), and lasers of the target wavelength are placed on the other two focal lines (2a) and (2c), respectively. Dye cells (4a) (4b) as laser oscillation elements that generate light are arranged. The dye cells (4a) (4b) have an inner diameter of 4 mm, for example, as shown in FIG.

Quartz window plates (9) at both ends of a transparent quartz tube (8) with an outer diameter of 6 m
(9), and an inlet (1o) and an outlet (11) for the dye solution are provided in the middle.1 Dye solution stored in a dye solution reservoir (not shown) (the dye is dissolved to a predetermined concentration with a solvent) ) is circulated through the transparent quartz tube (8) using a circulation pump (not shown).

In the configuration shown in Figure 1 above, the excitation light generated by the flash lamp (3), which is the excitation light source, excites the pigment that generates laser light of the target wavelength in the two pigment cells (4a) (4b). , generate the necessary laser light from these. Two elliptical cylinders (1a
) (lb) has an excitation light reflecting mirror inside, and the dye cell (lb) has an excitation light reflecting mirror inside.
4a) and (4b) are arranged on the focal line (2a) and (2c), so that the excitation light from the flash lamp (3) is efficiently irradiated onto the dye cells (4a) and (4b).

Next, FIG. 2 shows a specific application example of the present invention.
Reflective mirrors (5a) (6a), (5
b) Place (6b). In addition, on the output light side, there are shutters (12a) (12b) and a condensing lens (13a), respectively.
) (13b) via optical fiber (14a) (14
b), and the shutter (12
a) Opening and closing of (12b) is controlled by a shutter control circuit (15).

The operation when the apparatus shown in FIG. 2 is used in the above-mentioned cancer diagnostic apparatus will be explained.

One dye cell (4a) contains a dye D P S (Di
Assuming that a dioxane saturated solution of phenyl 5tilben) is flowing in, a flash lamp (3
), the fluorescence obtained from the DPS dye is multi-reflected between the reflecting mirrors (5a) and (6a), thereby being intensified and extracted to the outside as a laser beam (7a) with a wavelength of approximately 405 nm. Inside the other dye cell (4b) was an ethyl alcohol solution of Rhodamine 640 (concentration 0.1 m).
M) flows in, and the fluorescence from Rhodamine 640 is multi-reflected and intensified between the reflecting mirrors (5b) (6b), and as a result, it is extracted to the outside as a laser beam (7b) with a wavelength of approximately 630 nm.

Here, the shutters (12a) (12b) are controlled to open and close by control signals from the shutter control circuit (15). Laser light (7a) passed through shutter (12a) (12b)
) (7b) is condensed by condensing lenses (13a) (13b), enters the optical fibers (14a) (14b), and passes through the optical fibers (14a) (14b) to generate laser light. It is transmitted to the target object. The two laser beams (7a) (7b) passing through the shutters (12a) (12b) are controlled to open and close depending on the purpose, such as opening and closing at the same time, alternate opening and closing, etc., by control signals from the shutter control circuit (15). For example, when diagnosing cancer, one shutter (12a) is first opened, the other shutter (12b) is closed, and only a 405 nm laser light pulse is sent to discover cancer lesions, and then the shutter (12a) is opened. is closed, the shutter (12b) is opened, and a 630 nm laser light pulse is sent for use in treating cancer lesions.

Next, FIG. 3 shows another application example of the laser device according to the present invention. In this example, the dye cell (4a) (4
b) is not used to generate laser beams of different wavelengths, but is used for oscillation and amplification of laser beams of the same wavelength. For example, in the dye cells (4a) (4b), rhodamine 6
It is assumed that an ethyl alcohol solution of 40 dyes is flowing in at a concentration of 0.11 IIM. Flash lamp (3)
The excitation light from irradiates and excites the dyes in the dye cells (4a) and (4b). The fluorescence of rhodamine 640 generated in one dye cell (4a) is reflected by a reflecting mirror (5a) and a concave lens (
16), a combination of a convex lens (17) and a diffraction grating (18) is strengthened while reciprocating in the resonator, and a reflecting mirror (5a)
The laser light is extracted to the outside as a laser beam (7a). Here, the filter (19) between the flash lamp (3) and the dye cell (4a) is for adjusting the excitation light intensity from the flash lamp (3), and the diffraction grating (18) is It is used to reduce the intensity of laser light to an extent that does not cause damage. Also combination lens (16)
(17) increases the wavelength resolution by increasing the laser beam size incident on the diffraction grating (18), and decreases the laser energy density per unit area.
) is a beam expander to protect the beam from damage.

Laser light is incident in a plane perpendicular to the score lines of the diffraction grating (18), and the laser beam is rotated around the rotation axis parallel to the score lines of the diffraction grating (18).
), the diffracted light wavelength determined by this rotation is determined as the laser wavelength. That is, the diffraction grating (1
8) is used to change the laser wavelength. In addition,
It is also possible to use a prism as a wavelength variable element instead of the diffraction grating (18). In this case, a reflecting mirror is required after the prism so that the light dispersed through the prism returns to the dye cell (4a) side again.

The laser beam (7a) outputted from the reflection fi (5a) is reflected by the reflecting mirrors (20) and (21), enters the other dye cell (4b), and is amplified. Flash lamp (
The dye rhodamine 640 in the dye cell (4b) is excited to the upper level by the irradiation in step 3). At this time, one dye cell (
Since the laser light (7a) generated in cell 4a) enters and causes stimulated emission, the laser light (7b) obtained from the other dye cell (4b) is the amplified version of the laser light (7a) from the other dye cell. Become.

In the above embodiment, a two-wavelength oscillation device was explained, but
Laser light with 3 wavelengths, 4 wavelengths, etc. can be obtained. For example, when obtaining 3 wavelengths, as shown in Figure 4, 3 wavelengths are obtained.
Prepare two elliptical cylinders (la), (lb), and (lc), combine them so that one focal line (2b) of each is common, and place a flash lamp (3) on the common focal line (2b).
), and the dye cells (4a) (4b) (4c) are placed on the other three focal lines (2a) (2c) (2d).

The dyes in each dye cell (4a), (4b), and (4c) are excited by irradiation with the flash lamp (3), and each dye can generate laser light. Further, in order to obtain four wavelengths, the same thing as above may be performed by combining four elliptical cylinders (1a) (lb) (lc) (ld) as shown in FIG.

Although the laser device according to the above embodiment has been described with respect to a dye laser, the purpose and essence of the present invention is not limited to a dye laser.If a solid-state laser oscillation element is placed in place of a dye cell, the laser device can be used as a solid-state laser device. Can be used as For example, in Figures 1 and 2, instead of the two dye cells (4a) (4b), ruby crystals, Nd
:If YAG crystal laser oscillation elements are arranged, laser beams of 0.694 μm and 1.06 μm can be obtained from each at the same time. In this case, the reflecting mirror facing the crystal forming the laser resonator needs to have a high reflectance for each laser beam.

"Effects of the Invention" Since the present invention is configured as described above, conventionally, for example, 405
When laser beams of nm and 630 nm were required, two laser devices were used, resulting in high costs.

Also, a large installation space was required.

The present invention solves this problem, is inexpensive, requires less installation space, and has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a laser device according to the present invention, FIG. 2 is an explanatory diagram of a device to which the laser device of the present invention is applied, FIG. 3 is an explanatory diagram of another applied device of the present invention, and FIGS. 5 is an explanatory diagram of another embodiment of the present invention, FIG. 6 is a sectional view of a conventional dye laser device, and FIG. 7 is an explanatory diagram of FIG. 6 viewed from the side.
- FIG. 8 is an explanatory diagram of another conventional example. (1)... Laser head, (la) (lb) (l
c) (ld) - Elliptical cylinder, (2a) (2b) (2c
) (2d) (2e) ”'Focal line, (3)--Flash lamp (excitation light source), (4) (4a) (4
b) (4c) (4d) - Dye cell (laser oscillation element), (5) (5a) (5b) (6) (6a)
(6b)...Reflector, (7) (7a) (7b)
...Laser light, (8)...Transparent quartz tube, (9)...
Quartz window plate, (10)...Inlet, (11)...Outlet, (12a) (12b)-Shutter, (13a)
(13b) ・=Condensing lens, (14a) (14b)
...Optical fiber, (15)...Shutter control circuit,
(16)...Concave lens, (17)...Convex lens. (18)...diffraction grating, (19)...filter. Applicant: Hamamatsu Photonics Co., Ltd.

Claims (5)

[Claims] (1) A plurality of elliptical cylinders each having an inner surface as an excitation light reflecting surface are superimposed so that each has a common focal line to form a multiple elliptical cylinder, and the laser head made of the multiple elliptical cylinders is A laser device characterized in that an excitation light source is disposed on a common focal line, and laser oscillation elements are disposed on each of a plurality of other focal lines. (2) The laser device according to claim (1), wherein the laser oscillation element is a dye cell into which a dye solution of an appropriate concentration flows. (3) A claim in which one dye cell has a dye solution capable of generating a laser beam with a wavelength of 405 nm, and the other dye cell has a dye solution capable of generating a laser beam with a wavelength of 630 nm. (2) Laser device described. (4) Claim (1) wherein the laser oscillation element is a solid state laser oscillation element that generates laser light such as ruby or Nd:YAG.
) Laser device described. (5) As a resonator of one laser oscillation element, a combination of a laser beam expansion optical system, a dispersion element, and a reflecting mirror is provided,
A filter for adjusting the amount of excitation light emitted from the excitation light source is placed between one laser oscillation element and the excitation light source,
and a reflective optical system that guides the laser beam generated from one laser oscillation element into the other laser oscillation element (
1) The laser device described above.