JP2009018042A - Laser therapeutic instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser therapeutic instrument which enables the use of energy fed for the transpiration of teeth at a higher efficiency. <P>SOLUTION: The instrument is provided with a laser oscillator 20 which oscillates and outputs a mono-wavelength laser light, an optical parametric oscillator 40 which gets the laser light outputted from the laser oscillator 20 inputted as pump light 60 and converts at least a part of the pump light 60 inputted to a signal light 61 and an idler light 62 to be outputted and a handpiece 30 which has an irradiation chip 32 for simultaneously irradiating the signal light 61 and the idler light 62 outputted from the optical parametric oscillator 40 outside. When the wavelengths of the pump light 60, the signal light 61 and the idler light 62 are represented by λ<SB>p</SB>, λ<SB>s</SB>and λ<SB>i</SB>respectively, the optical photometric oscillator 40 receives the input of the pump light 60 with λ<SB>p</SB>of 1.35-1.75 μm while outputting the signal light 61 and the idler light 62 both with λ<SB>s</SB>and λ<SB>i</SB>of 2.72-3.42 μm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laser treatment apparatus, and more particularly to a treatment apparatus capable of outputting laser light having a wavelength suitable for transpiration of teeth and skin.

Conventionally, laser has been used for medical and dental treatments. In the treatment with a laser, the degree of absorption with respect to human tissue varies depending on the wavelength of the laser to be used. Therefore, a suitable wavelength is selected depending on the type of treatment. For example, in dental treatment, when performing transpiration (incision) of a tooth, an Er: YAG laser having a wavelength in the vicinity of 3 μm having a high absorption rate for water is suitable.
This is because hydroxyapatite, which accounts for 97% of the enamel of the tooth, forms hydrogen bonds in the hydration shell, but is tuned to the absorption wavelength derived from the OH (hydric acid) group stretching vibration in the hydration shell. Because it does.
Further, in the case of performing soft tissue incision, tissue hemostasis, etc., Nd: YAG laser (wavelength: 1.06 μm), Ho: YAG laser (wavelength: 2.1 μm) having a lower absorption rate with respect to water than Er: YAG laser. And a CO ₂ laser (wavelength: 10.6 μm) is suitable because the energy reaches the inside of the tissue.

  However, the Er: YAG laser not only has inferior energy conversion efficiency, but also has a significantly large optical transmission system loss compared to other lasers. More specifically, 98% or more of the input electric energy is converted into heat without being used, and 40% or more of the optical energy is lost in the waveguide or the optical component. It was very bad. In addition, in order to obtain sufficient energy, the power supply to be supplied must be increased, installation space is also required, and there is a problem that handling is not easy from the viewpoint of the operator who actually performs treatment. .

Patent Document 1 discloses a laser treatment apparatus that can evaporate teeth without using an Er: YAG laser. A schematic configuration of the laser optical system disclosed in Patent Document 1 is shown in FIG.
As shown in FIG. 8, a plurality of laser beams 504 and 506 having different wavelengths are simultaneously output from the laser oscillation unit 200. The output laser beams 504 and 506 are transmitted to the hand piece 700 through the flexible tube 600, and are irradiated to the treatment site from the tip of the irradiation chip 701 attached to the hand piece 700.

The laser oscillation unit 200 includes a laser oscillator 300, an optical parametric oscillator 400, and a mixing ratio adjuster 480.
Laser oscillator 300 includes a laser diode 320 and an Nd: YAG laser 340. The Nd: YAG laser 340 is excited by the excitation light 500 from the laser diode 320 having a wavelength of 808 nm, and generates a laser light 502 having a wavelength of 1.06 μm.
As shown in FIG. 9, the optical parametric oscillator 400 includes a non-linear optical crystal 420 made of LiNbO ₃ disposed between an incident mirror 440 and an output mirror 460. When the pump light L0 is incident, the optical parametric oscillator 400 is coupled to the signal light L1 and the idler. Light L2 is generated. The wavelengths of the signal light L1 and the idler light L2 can be appropriately set according to the arrangement angle of the nonlinear optical crystal 420, the intra-crystal lattice spacing, the crystal temperature, and the like.
Laser light 502 with a wavelength of 1.06 μm from laser oscillator 300 is incident on optical parametric oscillator 400 as pump light L0. Accordingly, the signal light L1 having a wavelength of 1.4 to 2.1 μm (hereinafter also referred to as 2 μm band laser light) and the idler light L2 having a wavelength of 2.1 to 4.3 μm (hereinafter, 3 μm band laser light). Also called).

  The mixing ratio adjuster 480 includes special filters 480a and 480b having different transmittances for the laser light 504 in the 2 μm band and the laser light 506 in the 3 μm band. The mixing ratio adjuster 480 can selectively use the special filters 480a and 480b in the optical paths of the laser beams 504 and 506, and can adjust the mixing ratio of the laser light 504 in the 2 μm band and the laser light 506 in the 3 μm band. It is like that.

  According to the apparatus of Patent Document 1, the Nd: YAG laser 340 is used, and the two-wavelength laser beams 504 and 506 simultaneously oscillated by the optical parametric oscillator 400 are mixed so that the mixing ratio is optimal for the case and the treatment site. After adjusting with the adjuster 480, the tip of the irradiation tip 701 attached to the hand piece 700 can be irradiated to the outside. In other words, a 2 μm-band laser beam 504 suitable for soft tissue incision and hemostasis, and a 3 μm-band laser beam 506 suitable for cutting hard tissue or ablating the surface of soft tissue are used in an appropriate mixing ratio. Since it can be used, it is suitable for operations in various medical and dental cases.

JP 2002-125982 A

The laser treatment apparatus of Patent Document 1 appropriately uses a 2 μm-band laser beam 504 suitable for soft tissue incision, hemostasis, and the like, and a 3 μm-band laser beam 506 suitable for hard tissue cutting or soft tissue surface ablation. Irradiate to the outside at a mixing ratio. Here, the laser beam 504 in the 2 μm band cannot be used for transpiration of teeth. Since the laser beam 504 in the 2 μm band has a penetration depth of 1000 times or more than the laser beam 506 in the 3 μm band with respect to the tooth, if the tooth is irradiated together with the laser beam 506 in the 3 μm band, the pulp is seriously damaged. May cause serious thermal tissue damage. Therefore, when the purpose is to evaporate the teeth, only the laser beam 506 in the 3 μm band is selectively transmitted by the mixing ratio adjuster 480 or the laser beam 506 in the 3 μm band is applied to the teeth by another optical system. It is necessary to block the irradiation. In this case, the energy spent to generate the 2 μm band laser beam 504 is not used for tooth evaporation. Therefore, the laser treatment apparatus of Patent Document 1 has room for improvement in terms of efficient transpiration of teeth.
The present invention has been made based on such a technical problem, and an object of the present invention is to provide a laser treatment apparatus that can use the input energy with high efficiency for the transpiration of teeth.

The absorption wavelength derived from the stretching vibration of the OH (hydric acid) group of the hydration shell in which hydroxyapatite (Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ ) occupying 97% of teeth, particularly enamel, is hydrogen-bonded. An Er: YAG laser with a tuned laser wavelength is suitable for tooth transpiration. However, as described above, the Er: YAG laser has problems such as extremely low energy efficiency. Therefore, the present inventor has conceived of adjusting two wavelengths converted by an optical parametric oscillator used in Patent Document 1 to a band that can be used for tooth evaporation.

Here, when pump light is incident on the optical parametric oscillator, signal light and idler light are generated. When the wavelengths of the pump light, signal light, and idler light are λ _P , λ _S, and λ _i , respectively, the following equation (1) is established. As described in Patent Document 1, the following formula (1) can be used depending on the arrangement angle of the nonlinear optical crystal constituting the optical parametric oscillator, the lattice spacing in the crystal, the crystal temperature, etc. (hereinafter referred to as the specification of the nonlinear optical crystal). Accordingly, the wavelength of the signal light (λ _S ) and the wavelength of the idler light (λ _i ) can be set as appropriate. Therefore, in the present invention, the two wavelengths converted by the optical parametric oscillator are both adjusted to a band that can be used for tooth transpiration.
_{1 / λ P = 1 / λ} S + 1 / λ i ... (1)

Based on this idea, the laser treatment apparatus of the present invention includes a laser oscillator that oscillates and outputs a single-wavelength laser beam, a laser beam output from the laser oscillator as a pump beam, and a pump beam that is input. An optical parametric oscillator that converts and outputs signal light and idler light, where the wavelength of the signal light is λ _S and the wavelength of the idler light is λ _i , the optical parametric oscillator has λ _S and λ _i Both are output in the range of 2.72 to 3.42 μm.

In the laser treatment apparatus of the present invention, lambda _S and lambda _i is preferably in the range of 2.78～3.17Myuemu. This range is a more preferable wavelength region for the transpiration of the tooth and the protection of the dental pulp in consideration of the water absorption rate, the water thermal relaxation time, and the light penetration depth.
In the laser treatment apparatus of the present invention, the laser oscillator is preferably a fiber laser oscillator or a fiber amplifier. The fiber laser oscillator or the fiber amplifier can oscillate and output laser light (pump light) having a wavelength suitable for obtaining signal light and idler light having a wavelength of 2.78 to 3.17 μm. This preferred wavelength range is 1.39 to 1.585 μm, and 1.55 μm is recommended in practice.
Furthermore, in the laser treatment apparatus of the present invention, a hand piece having an irradiation tip for simultaneously irradiating the signal light and idler light output from the optical parametric oscillator to the outside can be provided. In this case, an optical parametric oscillator can be incorporated in the hand piece. This laser treatment device transmits pump light to an optical parametric oscillator with low loss using a low-cost quartz optical fiber with low loss for wavelengths in the range of 1.39 to 1.585 μm. it can.
In addition, when the laser treatment apparatus of the present invention is used as a dental treatment apparatus, the signal light and idler light output from the optical parametric oscillator are maintained in the output state and irradiated onto the teeth. It can be.

As described above, according to the laser treatment apparatus of the present invention, the wavelength of the signal light and the wavelength of the idler light converted by the optical parametric oscillator are adjusted within the range of 2.72 to 3.42 μm, and the signal light Since both the idler light and the idler light can be used for the transpiration of the teeth, the utilization efficiency of the input energy can be improved. Further, the transpiration rate of the teeth can be increased as compared with the case where either the signal light or the idler light is not used.
Further, by incorporating an optical parametric oscillator in the hand piece, an optical fiber made of quartz can be used, so that the cost can be reduced.
Furthermore, the energy efficiency can be improved, and the power supply capacity can be made smaller than that of a device using a conventional Er: YAG laser. As a result, the entire device is lighter and smaller, so that the operator can easily handle it.

<First Embodiment>
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 1 is a diagram showing a schematic configuration of a laser treatment apparatus 10 according to a first embodiment of the present invention.
The laser treatment apparatus 10 includes a laser oscillator 20, a hand piece 30, and a waveguide 50 that transmits laser light oscillated and output from the laser oscillator 20 to the hand piece 30. The body 31 of the hand piece 30 incorporates an optical parametric oscillator 40 that converts the wavelength of the laser light transmitted through the waveguide 50.
This laser treatment apparatus 10 uses a laser beam (signal light) having a wavelength of 1.55 μm outputted from the laser oscillator 20 (pump light 60) in the range of 2.72 to 3.42 μm by the optical parametric oscillator 40. 61 and idler light 62) are converted into wavelengths and output from the irradiation chip 32 of the hand piece 30. The surgeon holds the hand piece 30 and irradiates the treatment site with the laser light output from the irradiation chip 32.

The laser oscillator 20 oscillates laser light having a wavelength of 1.55 μm from a so-called optical fiber laser using 0.98 μm excitation light, and outputs the laser light to the waveguide 50.
The laser oscillator 20 includes an LD (Laser Diode; semiconductor laser) 21 that is an excitation light source. From the LD 21 side, an isolator (Isolator) 22, an FBG (Fiber Bragg Grating) 23, and an EDF (EDF). Erbium Doped Fiber) 24, Q switch 25, and FBG 26 are arranged on the waveguide 27 in this order.

The LD 21 outputs laser light having a wavelength of 0.98 μm as excitation light. For example, an InGaAs semiconductor laser can be used as the LD 21. Of course, the LD 21 of the present invention is not limited to this.
The laser oscillator 20 includes a plurality of LDs 21. This is to increase the output value of the laser light oscillated by the laser oscillator 20. However, it goes without saying that it is not necessary to provide a plurality of LDs 21 as long as a large output can be obtained by a single LD 21.

  The excitation light output from the LD 21 is input to the EDF 24 via the isolator 22 and the FBG 23. The EDF 24 is a single-mode polarization maintaining optical fiber in which Er (erbium) is doped in quartz glass. Er (erbium) contained in the EDF 24 has a transition in a wavelength band of 1.5 μm. Therefore, the excitation light input to the EDF 24 is amplified to light having a wavelength of 1.55 μm while going back and forth through the EDF 24. As the wavelength of the excitation light, in addition to the aforementioned 0.98 μm, an InGaAs-based semiconductor laser of 1.48 μm and a GaAlAs-related semiconductor laser of 0.82 μm can be used.

  The light having a wavelength of 1.55 μm is resonated between the FBG 23 and the FBG 26, pulsated by the Q switch 25, and output to the waveguide 50. Here, the FBG 23 totally reflects light having a wavelength of 1.55 μm, and the FBG 26 partially reflects light having a wavelength of 1.55 μm. As the FBG 26, for example, one that transmits about 10% of light having a wavelength of 1.55 μm can be used.

  Laser light having a wavelength of 1.55 μm output from the laser oscillator 20 is input to the optical parametric oscillator 40 built in the hand piece 30 through the waveguide 50. As the waveguide 50, for example, a polarization maintaining optical fiber can be used. Since this optical fiber is widely used for communication, it is inexpensive and has an advantage that laser light having a wavelength of 1.55 μm can be transmitted with low loss. The laser treatment apparatus 10 that can use an optical fiber for communication in the waveguide 50 between the laser oscillator 20 and the hand piece 30 has a great cost advantage.

The optical parametric oscillator 40 has a basic configuration in which a nonlinear optical crystal 41 is arranged between a front mirror 42 and a rear mirror 43 as shown in FIG. When the laser light (pump light 60) having a wavelength of 1.55 μm transmitted through the waveguide 50 is input to the optical parametric oscillator 40 via the condenser mirror 44, signal light 61 and idler light 62 are generated. Here, when the wavelengths of the pump light 60, the signal light 61, and the idler light 62 are λ _P , λ _S, and λ _i , respectively, the equation (1) is established as described above.
1 / λ _P = 1 / λ _S + 1 / λ _i ... (1)
Laser light having a wavelength λ _P of 1.55 μm is input to the optical parametric oscillator 40 as the pump light 60. If the wavelength λ _S of the signal light 61 is adjusted to 3.0 μm, the wavelength λ _i of the idler light 62 is 3.2 μm according to the above equation (1).
The signal light 61 and the idler light 62 generated by the optical parametric oscillator 40 are irradiated from the irradiation chip 32 of the hand piece 30 to the outside. Since the signal light 61 and the idler light 62 do not pass through the special filters 480a and 480b disclosed in Patent Document 1, the signal light 61 and the idler light 62 are irradiated to the outside while maintaining the state output from the optical parametric oscillator 40. Note that “the output state is maintained” excludes inevitable losses.

As the nonlinear optical crystal 41, first, as a bulk type, LiB ₃ O ₅ crystal, KTiOOASO ₄ crystal, RbTiOPO ₄ crystal, βBaB ₂ O ₄ crystal, KTiOPO ₄ crystal, LiIO ₃ crystal, LiNbO ₃ crystal and BiB ₃ O _{6 are used.} Crystals can be used. Among these, it is preferable to use KTiOOASO ₄ crystal and LiNbO ₃ crystal as the nonlinear optical crystal 41.
Second, a quasi phase matching (QPM) crystal can be used, and LiNbO ₃ in which a periodically poled structure is arbitrarily formed in the crystal is most widely used, PPLN (Periodically Poled Lithium Niobate), or MgO Is abbreviated as doped PPMgLN.

  In addition to adjusting the composition of the nonlinear optical crystal 41, the wavelengths of the signal light 61 and the idler light 62 can be adjusted as appropriate by changing the shape of the nonlinear optical crystal 41 and the angles with respect to the front mirror 42 and the rear mirror 43.

Here, FIG. 2 is a graph showing the result of FT-IR (Fourier Transfer Infrared Spectrometer) analysis of water. As shown in FIG. 2, water has a peak of absorbance at a wave number (1 / cm) of around 3400. This peak approximates the absorption wavelength derived from the OH (hydric acid) group stretching vibration of water, which is a hydration shell in which hydroxyapatite (Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ ) is hydrogen bonded. That is, the wave number (wavelength) in the range of the convex portion of the graph curve including the peak of FIG. 2 is effective for the transpiration of the tooth. On the basis of this, the present invention has the signal light 61 and idler light in the wavelength range of 2.72 to 3.42 μm (wave number 3676 to 2974 (1 / cm)) at which the water absorbance is about 10% or more. 62 is generated by the optical parametric oscillator 40. At this time, the wavelength λ _P of the pump light 60 is in the range of 1.36 to 1.71 μm. Further, as shown in FIG. 2, since the absorbance is about 95% or more in the wavelength range of 2.959 to 3.113 μm, it is preferable that both the signal light 61 and the idler light 62 are converted into this range. At this time, the wavelength λ _P of the pump light 60 is in the range of 1.4795 to 1.5565 μm.

The laser treatment apparatus 10 according to the present embodiment can simultaneously output the signal light 61 having a wavelength λ _S of 3.0 μm and the idler light 62 having a wavelength λ _i of 3.2 μm from the irradiation chip 32. The signal light 61 and the idler 62 light both have a wavelength in the range of 2.72 to 3.42 μm. Therefore, when the laser treatment apparatus 10 according to the present embodiment is applied to the transpiration of a tooth, both the generated signal 61 light and idler light 62 can be irradiated on the tooth. This means that the input energy can be used without waste and the speed of tooth transpiration can be increased as compared with Patent Document 1 in which laser light in the 2 μm band cannot be used for transpiration of teeth.

In the optical parametric oscillator 40, the signal light 61 and the idler light 62 converted from the pump light 60 are about 51.6% of the energy in the signal light 61, assuming that the energy of the pump light 60 is 100. About 48.4% of the energy is distributed to idler light 62. Therefore, for example, when the signal light 61 and the idler light 62 are used together as compared with a case where the idler light 62 cannot be used, the teeth can be evaporated with energy about three times.
In this embodiment, the wavelengths of the signal light 61 and the idler light 62 are in the range of 2.72 to 3.42 μm. In FIG. 2, the absorbance is 30% or more (thermal relaxation time is about 10 μsec or less, light penetration depth). Is within the range of 2.78 to 3.17 μm, which can provide about 3 μm or less), and also within the range of 2.959 to 3.113 μm where the absorbance is 95% or more. It is preferable for safety.

Here, the wavelength (λ _p ) of the pump light 60 is set to 1.35 μm, 1.45 μm, 1.55 μm, 1.65 μm, and 1.75 μm, and the wavelength (λ _s ) of the signal light 61 is set to 2.72-3. The variation curves of the wavelength (λ _s ) of the signal light 61 and the wavelength (λ _i ) of the idler light 62 when adjusted to .42 μm are shown in the graph of FIG. In addition, this curve is calculated | required by above-mentioned Formula (1).
3 indicates that both the wavelength (λ _s ) of the signal light 61 and the wavelength (λ _i ) of the idler light 62 are in the range of 2.72 to 3.42 μm. Show. 3, when the wavelength (λ _p ) of the pump light 60 is in the range of 1.35 to 1.75 μm, both the wavelength (λ _s ) of the signal light 61 and the wavelength (λ _i ) of the idler light 62 are 2. It can be adjusted within the range of 72 to 3.42 μm. However, when the wavelength (λ _p ) of the pump light 60 is 1.35 μm or 1.75 μm, the wavelength (λ _s ) of the signal light 61 and the wavelength (λ _i ) of the idler light 62 are 2.72 to It cannot be adjusted within the range of 3.42 μm. Therefore, in order to adjust the wavelength (λ _s ) of the signal light 61 and the wavelength (λ _i ) of the idler light 62 in a wider range to a range of 2.72 to 3.42 μm, the wavelength (λ _{p of the} pump light 60 ) In the range of 1.45 to 1.65 μm.

The laser treatment apparatus 10 according to the present embodiment can perform dental treatment. Specifically, in addition to the transpiration of hard teeth, treatments such as calculus removal, root canal enlargement, root canal sterilization, periodontal pocket irradiation, root apex removal, melanin pigment removal, and reverse root canal formation Can do. In this case, it is necessary to use the irradiation chip 32 in a form corresponding to each case.
In addition to the signal light 61 and the idler light 62 adjusted within the range of 2.72 to 3.42 μm, the laser treatment apparatus 10 supplies water, air, and other fluids from the irradiation chip 32 of the hand piece 30. A discharging mechanism can be provided.

In the above description, the wavelengths of the signal light 61 and the idler light 62 are described based on the absorbance of water. However, the wavelengths of the signal light 61 and the idler light 62 can be specified from the following viewpoints.
The main component constituting the tooth is hydroxyapatite (hereinafter referred to as HA), which is about 97% in enamel and about 70% in dentin. The basic principle of transpiration of teeth by laser light is that the hydration shell, which is the key to HA bonding with hydrogen, that is, irradiating laser light tuned to the absorption wavelength derived from the stretching vibration of water molecules, There is to destroy. If there are two wavelengths that break this hydration shell and can be tuned to the absorption wavelength of HA, it can be easily assumed that it is more effective for transpiration.

FIG. 4 shows the infrared absorption spectrum characteristics of HA, and an absorption peak exists at the wave number 3581 [1 / cm] on the left side of the figure. This absorption is a stretching vibration absorption wavelength derived from the OH group of HA, and is approximately 2.8 μm.
Therefore, when the wavelength is converted by the optical parametric oscillator 40 and used for transpiration of teeth, it is effective to generate signal light 61 and idler light 62 in the vicinity of 2.8 μm.
As shown in FIG. 2, the absorbance at a wavelength of 2.8 μm is about 35%, but the wavelength λ _S of the signal light 61 is fixed at 2.8 μm, and the wavelength λ _p of the pump light 60 is from 1.4 μm to about 1.51 μm. As it is increased, the total absorbance of the signal light 61 and idler light 62 (λ _S + λ _i ) draws a mountain-shaped curve as shown in FIG. 5, and a maximum value of about 65% is obtained. From the curve of FIG. 5, it is ideal to use the pump light 60 having a wavelength λ _p of about 1.46 μm, and the wavelength λ _i of the idler light 62 at this time is 3.05 μm.

When the wavelength is 3.05 μm, an absorbance of about 100% is obtained, so that the total energy selectively bears the hydration shell destruction, and the signal light 61 having the wavelength λ _S of 2.8 μm directly acts on the HA. It contributes to the destruction of HA more effectively.
In the above case, as long as the phase matching condition ν _p = ν _s + ν _i (ν: laser frequency) is satisfied, the ratio of the energy Es of the signal light 61 and the energy Ei of the idler light 62 is Es: Ei = 1: 0.92, and both have the same level of energy.

A TDFA (Tm-doped optical fiber amplifier) can be used as the laser light source of the pump light 60 for obtaining the signal light 61 having the wavelength λ _S of 2.8 μm. TDFA emits wavelengths in the 1.45 μm band. Therefore, if λ _{p of the} pump light 60 is 1.48 μm using TDFA, the signal light 61 having the wavelength λ _S of 2.8 μm and the idler light having the wavelength λ _i of 3.14 μm are obtained from the equation (1). 62 can be obtained.

<Second Embodiment>
FIG. 6 is a diagram showing a schematic configuration of a laser treatment apparatus 70 according to the second embodiment of the present invention.
The laser treatment apparatus 70 includes a laser oscillator 80, a hand piece 30, and a waveguide 50 that transmits laser light generated by the laser oscillator 80 to the hand piece 30. The laser treatment apparatus 70 is different from the laser treatment apparatus 10 of the first embodiment in the laser oscillator 80, but the configurations of the waveguide 50 and the hand piece 30 are the same as those of the laser treatment apparatus 10. Therefore, the waveguide 50 and the hand piece 30 are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted.

The laser oscillator 80 of the laser treatment apparatus 70 amplifies seed light having a wavelength of 1.55 μm capable of high-speed modulation control, and generates pump light 60 supplied to the optical parametric oscillator 40. The laser oscillator 80 is based on an amplification method called a MOPA (Master Oscillator Power Amplifier) method.
The laser oscillator 80 includes a DFB-LD (Distributed Feedback Laser Diode) 81 that oscillates and outputs a seed light having a wavelength of 1.55 μm. From the DFB-LD 81 side, an isolator 84 and a TFB are provided. (Tapered Fiber Bundle) 85, EDF 86, isolator 87, TFB 88, EDF 89, and isolator 90 are disposed on the waveguide 91 in this order. In the laser oscillator 80, an SM-LD (Single Mode Laser Diode) 82 is connected to a waveguide 91 between the isolator 84 and the TFB 85 via the TFB 85. Further, in the laser oscillator 80, a plurality of MM-LDs (Multi Mode Laser Diodes) 83 are connected to the waveguide 91 between the isolator 87 and the TFB 88 via the TFB 88.

In the laser oscillator 80, since the seed light oscillated from the DFB-LD 81 has a low output value, it is amplified at the subsequent stage. Amplification is performed in two stages.
The first-stage amplification is performed in an EDF (Erbium Doped Fiber) 86. The EDF 86 is a single mode. The seed light is coupled to the core of the EDF 86 and the pump light output from the SM-LD 82 is taken into the clad of the EDF 86, whereby the seed light is amplified. This amplification improves the beam quality of the seed light. The excitation light output from the SM-LD 82 has a wavelength of 0.98 μm.

The second stage amplification is performed in the EDF 89. That is, the light amplified by the EDF 86 (first amplified light) passes through the isolator 87 and the TFB 88 and is input to the EDF 89. At this time, the first amplified light is coupled to the core of the EDF 89. On the other hand, excitation light having a wavelength of 0.915 μm output from the MM-LD 83 is taken into the cladding of the EDF 89 via the TFB 88. Therefore, the first amplified light is amplified to the second amplified light in the EDF 89. The second amplified light having a wavelength of 1.55 μm is input as pump light 60 to the optical parametric oscillator 40 built in the hand piece 30 through the waveguide 50. Optical parametric oscillator 40, as described in the first embodiment, for example, a wavelength λp is the wavelength lambda _S pump light 60 of 1.55μm is 3.0μm signal light 61 and the wavelength lambda _i is 3.2μm It is converted into idler light 62 and output.

<Third Embodiment>
FIG. 7 is a diagram showing a schematic configuration of a laser treatment apparatus 100 according to the third embodiment of the present invention.
The laser treatment apparatus 100 includes a laser oscillator 80, an optical parametric oscillator 110, a hand piece 120, a waveguide 130 that transmits laser light output from the laser oscillator 80 to the optical parametric oscillator 110, and an optical parametric oscillator 110. And a waveguide 131 that transmits the output laser light to the hand piece 120.
This laser treatment apparatus 100 is different from the laser treatment apparatus 70 of the second embodiment in that an optical parametric oscillator 110 is provided separately from the hand piece 120, but the configuration of the laser oscillator 80 is the first. This is the same as the laser treatment apparatus 70 of the second embodiment. Therefore, the laser oscillator 80 is denoted by the same reference numeral as in the second embodiment, and the description thereof is omitted.

The optical parametric oscillator 110 of the laser treatment apparatus 100 has a basic configuration in which a nonlinear optical crystal 111 is disposed between a front mirror 112 and a rear mirror 113 as shown in FIG. When laser light having a wavelength of 1.55 μm transmitted through the waveguide 130 (hereinafter referred to as pump light 117) is input to the above basic configuration via the condensing mirror 114 and the reflecting mirror 115, the signal light 118 and the idler light 119 are used. Is generated. Here, assuming that the wavelengths of the signal light 118 and the idler light 119 are λ _S and λ _i , respectively, as described in the first embodiment, the signal light 118 having the wavelength λ _S of 3.0 μm and the wavelength λ _i are 3.2 μm idler light 119 can be obtained. The signal 118 light and idler light 119 generated by the optical parametric oscillator 110 are transmitted to the hand piece 120 through the condenser lens 116 and the waveguide 131 and are irradiated from the irradiation chip 121 to the outside. Since the signal light 118 and idler light 119 transmitted through the waveguide 131 have a wavelength in the vicinity of 3.0 μm, if the waveguide 131 is made of an optical fiber made of quartz, the loss becomes extremely large. Therefore, the waveguide 131 needs to be made of an infrared fiber that is more expensive than an optical fiber made of quartz.

As described above, the laser treatment apparatus (10, 70, 100) according to the first to third embodiments performs signal conversion by converting the wavelength of the pump light 60, 117 by the optical parametric oscillator (40, 110). The wavelengths of the light 61 and 118 and the idler light 62 and 119 can be in the range of 2.72 to 3.42 μm, preferably 2.78 to 3.17 μm. The signal lights 61 and 118 and the idler lights 62 and 119 having this wavelength can be used for tooth transpiration. Therefore, the input energy can be efficiently used for the transpiration of the teeth, and the transpiration rate can be increased.
According to the second (3) embodiment in which the seed light is amplified to generate the pump lights 60 and 117 for the optical parametric oscillator 40 (110), it is necessary to provide a plurality of LDs 21 in order to obtain the same high output. Compared to the first embodiment, the laser oscillator 80, and hence the laser treatment apparatus 70, can be manufactured at low cost and in a small size.

  In the first and second embodiments, since the optical parametric oscillator 40 is built in the hand piece 30, a low-cost quartz optical fiber is provided between the laser oscillator 20 (80) and the optical parametric oscillator 40. There are advantages that can be used. On the other hand, according to the third embodiment in which the optical parametric oscillator 110 is separated from the hand piece 120, the hand piece 120 can be reduced in weight and size. Can be obtained.

It is a figure showing a schematic structure of a laser treatment apparatus of a 1st embodiment concerning the present invention. It is a graph which shows the result of having analyzed water FT-IR. The wavelength (λ _p ) of the pump light was set to 1.35 μm, 1.45 μm, 1.55 μm, 1.65 μm, and 1.75 μm, and the wavelength (λ _s ) of the signal light was adjusted to 2.72 to 3.42 μm. It is a grab showing the relationship between the wavelength of signal light (λ _s ) and the wavelength of idler light (λ _i ). It is a graph which shows the infrared absorption spectrum characteristic of a hydroxyapatite. It is a graph which shows the total light absorbency of signal light and idler light ((lambda) _S + (lambda) _i ) when the wavelength (lambda) _{p of} pump light is increased from 1.4 micrometers to about 1.51 micrometers. It is a figure which shows schematic structure of the laser treatment apparatus of 2nd Embodiment which concerns on this invention. It is a figure which shows schematic structure of the laser treatment apparatus of 3rd Embodiment which concerns on this invention. 1 is a diagram illustrating a schematic configuration of an apparatus disclosed in Patent Document 1. FIG. 2 is an explanatory diagram of an optical parametric oscillator disclosed in Patent Document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,70,100 ... Laser treatment apparatus 20,80 ... Laser oscillator 30,120 ... Hand piece 40,110 ... Optical parametric oscillator 60,117 ... Pump light, 61,118 ... Signal light, 62,119 ... Idler light

Claims (5)

A laser oscillator that oscillates and outputs a single wavelength laser beam;
An optical parametric oscillator that inputs the laser light output from the laser oscillator as pump light and converts the input pump light into signal light and idler light; and
When the wavelength of the signal light is λ _S and the wavelength of the idler light is λ _i ,
The optical parametric oscillator outputs the signal light and the idler light having λ _S and λ _i of 2.72 to 3.42 μm. 2. The laser treatment apparatus according to claim 1, wherein the λ _S and the λ _i are in a range of 2.78 to 3.17 μm.   The laser treatment apparatus according to claim 1, wherein the laser oscillator is a fiber laser oscillator. A hand piece having an irradiation tip for simultaneously irradiating the signal light and the idler light output from the optical parametric oscillator to the outside;
The laser treatment apparatus according to claim 1, wherein the optical parametric oscillator is built in the hand piece. The laser treatment device is a dental treatment device,
The laser treatment apparatus according to claim 1, wherein the signal light and the idler light output from the optical parametric oscillator are applied to a tooth while maintaining an output state.

Images