JPH0537064A - Solid state variable wavelength laser - Google Patents

Abstract

PURPOSE:To obtain a laser light having an arbitrary wavelength over an entire range of 205-1100nm including a wavelength range of 550-670nm by a solid state variable wavelength laser using a titanium sapphire as a laser medium. CONSTITUTION:A second harmonic wave of a titanium sapphire laser is generated from a titanium sapphire laser basic wave to be oscillated from a titanium sapphire laser oscillator 9 by a second harmonic wave generator 17 of the titanium sapphire laser Further, a laser light having a wavelength band of 550-670nm can be generated by a difference frequency generation from a second harmonic wave of the laser and a basic wave of the laser for oscillating a difference frequency generating titanium sapphire laser oscillator 24 by a difference frequency wave generator 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state wavelength tunable laser device.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a solid-state wavelength tunable laser device using titanium sapphire as a laser medium.
Is a YAG laser oscillator for excitation that oscillates laser light (YAG laser fundamental wave) having a wavelength of 1064 nm, 2 is Y
From the YAG laser fundamental wave oscillated by the AG laser oscillator 1, 1 / λ ₂ = 1 / λ ₁ + 1 / λ ₁ (1) (λ ₁ : fundamental wave, λ ₂ : second harmonic) relationship (second YAG laser second harmonic generator for generating laser light (YAG laser second harmonic) having a wavelength of 532 nm by means of harmonic generation), and YAG laser second harmonic generator 3 generated by the YAG laser second harmonic generator 2. And, of the YAG laser fundamental wave that has not been converted into the second harmonic wave in the YAG laser second harmonic wave generator 2, transmits the YAG laser fundamental wave component and reflects only the YAG laser second harmonic wave component. Dichroic mirror, 4 is a beam damper for blocking the YAG laser fundamental wave transmitted through the dichroic mirror 3, and 5 is a YAG laser reflected by the dichroic mirror. By transmitting a portion of the over the second harmonic, a half mirror for reflecting the remaining lens for converging the YAG laser second harmonic transmitted through the half mirror 5 6, 7 and reflected by the half mirror 5 Y
Total reflection mirror that reflects the second harmonic of the AG laser, 8
Is the second YAG laser reflected by the total reflection mirror 7.
A lens for converging harmonics.

Reference numeral 9 denotes a titanium sapphire laser oscillator. The titanium sapphire laser oscillator 9 reflects a second harmonic of the YAG laser converged by the lens 6, and transmits a dichroic mirror 11 having another wavelength. Y reflected by the dichroic mirror 11
A titanium sapphire laser rod 10 for oscillation that is excited by the incidence of the second harmonic of the AG laser to generate light having a wavelength of 670 to 1100 nm, and a resonance for resonating the light generated by the titanium sapphire laser rod 10 for oscillation. Front mirror 12 and end mirror 13 of the vessel, and the titanium sapphire laser rod for oscillation 1
A wavelength tuning element (wavelength selection element) 14 such as a birefringent filter that allows only light having a specific wavelength to pass therethrough and scatters light having other wavelengths out of light having a wavelength component of 670 to 1100 nm generated by 0. And a titanium sapphire laser fundamental wave having an arbitrary wavelength between 670 and 1100 nm, which reaches a certain light intensity level by being resonated by the end mirror 13 and the front mirror 12 and is transmitted through the front mirror 12, and The dichroic mirror 16 that reflects the second harmonic of the YAG laser converged by the lens 8 and the second harmonic of the YAG laser reflected by the dichroic mirror 16 are excited by being incident, and the dichroic mirror 1 is excited.
The titanium sapphire laser rod 15 for amplification which amplifies the light intensity of the titanium sapphire laser fundamental wave which permeate | transmits 6 and injects.

In the titanium sapphire laser oscillator 9 described above, the wavelength of the titanium sapphire laser fundamental wave oscillated from the titanium sapphire laser oscillator 9 is set to 670 to 1 by rotating the angle of the wavelength tuning element 14.
It can be set to any specific wavelength in the wavelength range of 100 nm.

Further, 17 is a titanium sapphire laser rod 1 for amplifying the titanium sapphire laser oscillator 9.
5, a titanium sapphire laser second harmonic generator for generating a titanium sapphire laser second harmonic from the titanium sapphire laser fundamental wave emitted by the equation (1), and 18 a titanium sapphire laser second harmonic
Second harmonic of titanium sapphire laser generated by the harmonic generator 17, and second harmonic of titanium sapphire laser
From the titanium sapphire laser fundamental wave remaining without being converted in the harmonic generator 17, 1 / λ ₃ = 1 / λ ₁ + 1 / λ ₂ (2) (λ ₁ : fundamental wave, λ ₂ : second harmonic wave) , Λ ₃ : third harmonic)
(Third harmonic generation) to generate a titanium sapphire laser third harmonic, or from the titanium sapphire laser second harmonic generated by the titanium sapphire laser second harmonic generator 17 to (1) above.
It is a titanium sapphire laser third harmonic generation and fourth harmonic generator that generates a titanium sapphire laser fourth harmonic (second harmonic of titanium sapphire laser second harmonic light) according to the relation of the formula.

The titanium sapphire laser third harmonic generation / fourth harmonic generator 18 has a crystal cell having a nonlinear optical crystal for generating a third harmonic, or a nonlinear optical crystal for generating a fourth harmonic. Either of the crystal cells can be installed inside the generator body, and the titanium sapphire laser third harmonic or the titanium sapphire laser fourth can be changed by appropriately replacing the crystal cell.
Harmonics can be generated.

A titanium sapphire laser fundamental wave, a titanium sapphire laser second harmonic wave, and a titanium sapphire laser third harmonic wave, which have not been converted by the titanium sapphire laser third harmonic wave generator / fourth harmonic wave generator 18, are also generated. This is a prism for separating the titanium sapphire laser third harmonic or the titanium sapphire laser fourth harmonic generated by the fourth harmonic generator 18.

In the above-mentioned solid-state wavelength tunable laser device,
The YAG laser oscillator 1 is used for Y with a wavelength of 1064 nm.
When the AG laser fundamental wave is oscillated, the YAG laser second harmonic generator 2 generates a YAG laser second harmonic with a wavelength of 532 nm from the YAG laser fundamental wave.
The second harmonic of the AG laser is reflected by the dichroic mirror 3.

A part of the second harmonic of the YAG laser reflected by the dichroic mirror 3 is a half mirror 5.
Through the lens 6 and the dichroic mirror 11 and enters the titanium sapphire laser rod 10 for oscillation of the titanium sapphire laser oscillator 9 as excitation light,
The oscillation source titanium sapphire laser rod 10 emits light that is the source of the titanium sapphire laser fundamental wave.

On the other hand, a part of the second harmonic of the YAG laser reflected by the dichroic mirror 3 is reflected by the half mirror 5, passes through the total reflection mirror 7 and the lens 8, and
As excitation light, it is incident on the titanium sapphire laser rod 15 for amplification of the titanium sapphire laser oscillator 9, and the titanium sapphire laser rod 15 for amplification is excited,
Now, assuming that a titanium sapphire laser fundamental wave having a wavelength of 900 nm is oscillated from the titanium sapphire laser oscillator 9, the titanium sapphire laser fundamental wave having a wavelength of 900 nm is amplified by the titanium sapphire laser rod 15 for amplification.

Amplification titanium sapphire laser rod 1
The titanium sapphire laser fundamental wave having a wavelength of 900 nm amplified by 5 is incident on the titanium sapphire laser second harmonic generator 17, and from the titanium sapphire laser second harmonic generator 17, according to the relation of the above formula (1). The second harmonic of titanium sapphire laser having a wavelength of 450 nm is generated.

The second harmonic wave of titanium sapphire laser having a wavelength of 450 nm generated by the second harmonic wave generator 17 of titanium sapphire and the wavelength 9 remaining without being converted in the second harmonic wave generator of titanium sapphire laser 9
The titanium sapphire laser fundamental wave of 00 nm is incident on the titanium sapphire laser third harmonic generation / fourth harmonic generator 18, and from the titanium sapphire laser third harmonic generation / fourth harmonic generator 18, Due to the relationship of the formula 2) or the formula (1), a titanium sapphire laser third harmonic having a wavelength of 300 nm or a titanium sapphire laser fourth harmonic (a second harmonic of titanium sapphire laser second harmonic light) having a wavelength of 225 nm is generated. .

Further, the third harmonic generation of titanium sapphire laser and the third harmonic of titanium sapphire laser generated by the fourth harmonic generator 18 or the fourth harmonic of titanium sapphire laser and the third harmonic generation of titanium sapphire laser are also generated. The titanium sapphire laser fundamental wave and the titanium sapphire laser second harmonic that remain without being converted by the fourth harmonic generator 18 are separated by the prism 19.

In the above-mentioned solid-state wavelength tunable laser device, when the angle of the wavelength tuning element 14 is rotated to change the wavelength of the titanium sapphire laser fundamental wave oscillated from the titanium sapphire laser oscillator 9, the titanium sapphire laser By the second harmonic generator 17, 335
The titanium sapphire laser second harmonic wave having an arbitrary wavelength in the range of up to 550 nm is 223 by the titanium sapphire laser third harmonic wave generation / fourth harmonic wave generator 18.
It is possible to select and generate a titanium sapphire laser third harmonic having an arbitrary wavelength in the range of to 367 nm or a titanium sapphire laser fourth harmonic having an arbitrary wavelength in the range of 205 to 275 nm.

[0015]

However, in the above-mentioned solid-state wavelength tunable laser device, the titanium sapphire laser oscillator 9 is controlled by the physical properties of the titanium sapphire forming the oscillation titanium sapphire laser rod 10 and the amplification titanium sapphire laser rod 15. The wavelength of the titanium sapphire laser fundamental wave that can oscillate is 6
Since it is limited to the wavelength range of 70 to 1100 nm, the titanium sapphire laser second harmonic generator 17 etc.
Laser light of 50 nm or less can be obtained, but 55
It is not possible to obtain laser light in the wavelength range of 0 to 670 nm.

The present invention is intended to solve the above-mentioned problems, and it is 205-1 including the wavelength range of 550-670 nm.
It is an object of the present invention to provide a solid-state wavelength tunable laser device that can obtain laser light of any wavelength in the entire 100 nm range.

[0017]

A solid-state wavelength tunable laser device according to claim 1 of the present invention is a YAG laser oscillator 1 for oscillating a YAG laser fundamental wave, and a YAG laser oscillator oscillated by the YAG laser oscillator 1. YAG laser second harmonic generator 2 for generating a YAG laser second harmonic from a wave, and a titanium sapphire laser fundamental wave excited by the YAG laser second harmonic generated by the YAG laser second harmonic generator 2. A titanium sapphire laser oscillator 9, a titanium sapphire laser second harmonic generator 17 for generating a titanium sapphire laser second harmonic from a titanium sapphire laser fundamental wave oscillated by the titanium sapphire laser oscillator 9, and the YAG YA in the laser second harmonic generator 2 YAG laser second from YAG laser fundamental wave component that is not converted into laser second harmonic
YAG laser second harmonic generator 20 for generating a harmonic, and YAG laser second harmonic for generating the difference frequency
A titanium sapphire laser oscillator 24 for generating a difference frequency, which is excited by the second harmonic of the YAG laser generated by the harmonic generator 20 and oscillates a titanium sapphire laser fundamental wave, and is oscillated by the titanium sapphire laser oscillator 24 for generating the difference frequency. And a difference frequency generator 27 for generating a difference frequency laser beam from the titanium sapphire laser fundamental wave and the titanium sapphire laser second harmonic wave generated by the titanium sapphire laser second harmonic wave generator 17. is there.

The solid-state wavelength tunable laser device according to claim 2 of the present invention is a YA that oscillates a YAG laser fundamental wave.
A G laser oscillator 1, a YAG laser second harmonic generator 2 for generating a YAG laser second harmonic from a YAG laser fundamental wave oscillated by the YAG laser oscillator 1, and a YAG laser second harmonic generator 2 Titanium sapphire laser oscillator 9 that oscillates a titanium sapphire laser fundamental wave by being excited by the YAG laser second harmonic wave generated from the titanium sapphire laser fundamental wave generated from the titanium sapphire laser oscillator 9 A titanium sapphire laser second harmonic generator 17 for generating waves,
The YAG laser fundamental wave remaining without being converted into the second harmonic wave in the YAG laser second harmonic wave generator 2, and the YA generated by the YAG laser second harmonic wave generator 2.
YAG laser third harmonic generator 33 for generating YAG laser third harmonic by G laser second harmonic
And an optical parametric oscillator 37 for generating optical parametric oscillation laser light by the YAG laser third harmonic wave generated by the YAG laser third harmonic wave generator 33.

[0019]

In the solid-state wavelength tunable laser device according to claim 1 of the present invention, the titanium-sapphire laser second harmonic generator causes the titanium-sapphire laser oscillator 9 to oscillate the titanium-sapphire laser fundamental wave to the titanium-sapphire laser second harmonic. And a titanium sapphire laser oscillator 2 for generating a difference frequency with the second harmonic of the titanium sapphire laser generated by the difference frequency generator 27.
From the titanium sapphire laser fundamental wave that 4 oscillates,
By generating the difference frequency, laser light of an arbitrary wavelength in the wavelength range of 550 to 670 nm is generated.

In the solid-state wavelength tunable laser device according to claim 2 of the present invention, the YAG laser third harmonic generator 3 is used.
YAG laser oscillator 1 oscillates according to
Laser fundamental wave and YAG laser second harmonic generator 2
From the second harmonic of the YAG laser generated by
The third harmonic of the laser is generated, and Y is generated by the optical parametric oscillator 37 by the optical parametric oscillation.
Laser light of an arbitrary wavelength in the wavelength range of 550 to 670 nm is generated from the AG laser third harmonic.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment corresponding to claim 1 of the present invention. In the figure, the same reference numerals as those in FIG. 3 represent the same parts.

In the titanium sapphire laser oscillator 9 of this embodiment, the rotation angle of the wavelength tuning element 14 is the wavelength 75.
The angle is set to allow only 0 nm light to pass through well and to scatter light of other wavelengths, and the titanium sapphire laser oscillator 9 oscillates a titanium sapphire laser fundamental wave having a wavelength of 750 nm.

Therefore, from the titanium sapphire laser second harmonic generator 17, the wavelength 3
A 75 nm titanium sapphire laser second harmonic is generated.

Reference numeral 20 denotes a YAG laser fundamental wave having a wavelength of 1064 nm which is transmitted through the dichroic mirror 3 and
Similar to the laser second harmonic generator 2, a YAG laser second harmonic generator for generating a difference frequency for generating laser light (YAG laser second harmonic) having a wavelength of 532 nm according to the relationship of the above formula (1), 21 Is the YAG laser fundamental wave that remains without being converted into the second harmonic in the YAG laser second harmonic generator 20 for generating the difference frequency, and the YAG laser second harmonic for generating the difference frequency.
Y generated by the AG laser second harmonic generator 20
Of the second harmonics of the AG laser, a dichroic mirror that transmits the YAG laser fundamental wave component and reflects only the YAG laser second harmonic component, 22 is a beam damper that blocks the YAG laser fundamental wave that has passed through the dichroic mirror 21, Reference numeral 23 is a lens for converging the second harmonic of the YAG laser reflected by the dichroic mirror 21.

Reference numeral 24 denotes a titanium sapphire laser oscillator for generating a difference frequency. The titanium sapphire laser oscillator for generating a difference frequency 24 reflects the second harmonic of the YAG laser converged by the lens 23 and emits light of another wavelength. And a YAG laser second harmonic reflected by the dichroic mirror 41 are incident on the dichroic mirror 41 and the wavelengths of 670 to 110 are excited.
A titanium sapphire laser rod 42 that emits 0 nm light, and a front mirror 43 of a resonator for resonating the light generated by the titanium sapphire laser rod 42.
And a birefringent filter which transmits only light of a specific wavelength and scatters light of other wavelengths among light having a wavelength component of 670 to 1100 nm generated by the titanium sapphire laser rod 42 and the end mirror 44. And a wavelength tuning element 45 such as.

In the titanium sapphire laser oscillator 24 for generating the difference frequency described above, the titanium sapphire laser oscillator 2 is rotated by rotating the angle of the wavelength tuning element 45.
The wavelength of the titanium sapphire laser fundamental wave oscillated from 4 can be set to any specific wavelength in the wavelength range of 670 to 1100 nm. In this embodiment,
The titanium sapphire laser oscillator 24 for generating a difference frequency is
A titanium sapphire laser fundamental wave having a wavelength of 930 nm is oscillated.

Numeral 25 is detachably mounted between the titanium sapphire laser second harmonic generator 17 and the titanium sapphire laser third harmonic generation / fourth harmonic generator 18, and at the time of mounting, the titanium sapphire laser. Second
A 750 nm titanium sapphire laser fundamental wave that remains without being converted to the second harmonic in the harmonic generator 17;
Of the titanium sapphire laser second harmonics generated by the titanium sapphire laser second harmonic generator 17, the titanium sapphire laser fundamental wave component is transmitted, and only the titanium sapphire laser second harmonic component is reflected. , 26 reflect the second harmonic of the titanium sapphire laser reflected by the dichroic mirror 25, and the wavelength 930 at which the titanium sapphire laser oscillator 24 for generating a difference frequency oscillates.
nm titanium sapphire laser fundamental wave transmitting dichroic mirror, 27 is dichroic mirror 26
From the second harmonic of the titanium sapphire laser reflected by and the fundamental wave of the titanium sapphire laser transmitted through the dichroic mirror 26, 1 / λ ₆ = 1 / λ ₅ −1 / λ ₄ (3) (λ ₆ : difference frequency , Λ ₄ : light wave 1, λ ₅ : light wave 2, where λ ₄ >
A difference frequency generator for generating a laser beam having a wavelength of 628 nm according to the relationship of λ ₅ (difference frequency generation), 28 is a titanium sapphire laser second harmonic wave (light wave) having a wavelength of 375 nm left unconverted in the difference frequency generator 27. 2), the titanium sapphire laser fundamental wave (light wave 1) having a wavelength of 930 nm, and the wavelength 628n generated by the difference frequency generator 27
It is a Perimbroka prism for separating m difference frequency laser light.

In the solid-state wavelength tunable laser device shown in FIG. 1, the dichroic mirror 3 and the YAG for generating the difference frequency are used.
The beam damper 4 can be disposed between the laser second harmonic generator 20 and the laser second harmonic generator 20.

The operation of this embodiment will be described below.

When obtaining a laser beam having a wavelength of 628 nm, a titanium sapphire laser second harmonic generator 17 is used.
And the titanium sapphire laser third harmonic generation and fourth harmonic generator 18 are mounted with a dichroic mirror 25.

In this state, when the YAG laser oscillator 1 oscillates a YAG laser fundamental wave having a wavelength of 1064 nm, the YAG laser second harmonic generator 2 causes the YAG laser
A YAG laser second harmonic having a wavelength of 532 nm is generated from the laser fundamental wave, and the YAG laser second harmonic is generated by an optical element such as a dichroic mirror 3, a half mirror 5, a lens 6, or a total reflection mirror 7, a lens 8. The excitation light is guided to the titanium-sapphire laser oscillator 9, and the titanium-sapphire laser oscillator 9 oscillates a titanium-sapphire laser fundamental wave having a wavelength of 750 nm.

Furthermore, a titanium sapphire laser oscillator 9
The titanium sapphire laser second harmonic wave is generated from the titanium sapphire laser fundamental wave oscillated by the titanium sapphire laser second harmonic generator 17 according to the relationship of the above formula (1), and the titanium sapphire laser second harmonic wave is generated. Is reflected by the dichroic mirrors 25 and 26 and is incident on the difference frequency generator 27.

On the other hand, the YAG laser fundamental wave transmitted through the dichroic mirror 3 is incident on the YAG laser second harmonic generator 20 for generating the difference frequency, and the YAG laser second harmonic generator 20 is generated.
From the YAG laser fundamental wave by the laser second harmonic generator 20, Y of wavelength 532 nm is obtained from the relation of the above equation (1).
The second harmonic of the AG laser is generated, and the second harmonic of the YAG laser is guided by an optical element such as the dichroic mirror 21 and the lens 23 as excitation light to the titanium sapphire laser oscillator 24 for generating the difference frequency, and the difference is generated. Frequency generation titanium sapphire laser oscillator 24 to wavelength 9
A 30 nm titanium sapphire laser fundamental wave is oscillated, and the titanium sapphire laser fundamental wave passes through the dichroic mirror 26 and enters a difference frequency generator 27.

The difference frequency generator 27 has a wavelength of 9 generated by the titanium sapphire laser oscillator 24 for generating a difference frequency.
When the 30 nm titanium sapphire laser fundamental wave and the 375 nm wavelength titanium sapphire laser second harmonic wave are incident, the wavelength is calculated from the titanium sapphire laser fundamental wave and the titanium sapphire laser second harmonic wave according to the relationship of the formula (3). 628 nm laser light is generated and the titanium sapphire laser fundamental wave and titanium sapphire laser second harmonic that remains without being converted by the difference frequency generator 27 and the difference frequency laser light having a wavelength of 628 nm generated by the difference frequency generator 27 Are separated by the Perimbroker prism 28.

Further, in this embodiment, the wavelength tuning elements 14 and 4 are
Titanium sapphire laser oscillator 9 and titanium sapphire laser oscillator 2 for generating a difference frequency by rotating the angle 5
By changing the wavelength of each titanium sapphire laser fundamental wave oscillated by 4, the difference frequency generator 27
Laser light having an arbitrary wavelength in the wavelength range of 670 nm can be obtained.

On the other hand, in the solid-state wavelength tunable laser device shown in FIG. 1, the titanium-sapphire laser second harmonic generator 17 and the titanium-sapphire laser third harmonic are generated from the titanium-sapphire laser fundamental wave oscillated by the titanium-sapphire laser oscillator 9. When the titanium sapphire laser second harmonic or the titanium sapphire laser third harmonic or the fourth harmonic is generated by the fourth harmonic generator 18, the titanium sapphire laser second harmonic generator 17, the titanium sapphire laser first Dichroic mirror 25 from between the 3rd harmonic generation and 4th harmonic generator 18
By removing the titanium sapphire laser second harmonic generator 17, the titanium sapphire laser fundamental wave having a wavelength of 750 nm left unconverted, and the wavelength 375 generated by the titanium sapphire laser second harmonic generator 17.
When the titanium sapphire laser second harmonic wave and the titanium sapphire laser third harmonic wave generation / fourth harmonic wave generator 18 are made incident, the titanium sapphire laser third harmonic wave generation / fourth harmonic wave generator is generated. By 18,
A titanium sapphire laser fundamental wave and a titanium sapphire laser second wave are generated from the titanium sapphire laser fundamental wave and the titanium sapphire laser second harmonic wave according to the relationship of the above formula (2). The harmonics and the third harmonic of the titanium sapphire laser are separated by the Perimbroker prism 19.

At this time, the beam damper 4 is disposed between the dichroic mirror 3 and the YAG laser second harmonic generator 20 for generating the difference frequency so that excitation light does not enter the titanium sapphire laser oscillator 24 for generating the difference frequency. To do so.

In this embodiment, the wavelength corresponding to the fourth harmonic of the titanium sapphire laser is 188 nm,
This wavelength is shorter than 205 nm and does not satisfy the phase matching condition of wavelength conversion (generation of the fourth harmonic). Therefore, in this case (the wavelength of the titanium sapphire laser fundamental wave is 750 nm
In this case), the titanium sapphire laser third harmonic generation / fourth harmonic generator 18 cannot generate the titanium sapphire laser fourth harmonic.

FIG. 2 shows an embodiment corresponding to claim 2 of the present invention. In the figure, the same reference numerals as those in FIGS. 1 and 3 represent the same parts.

Reference numeral 29 is a YAG laser second harmonic generator 2
Second YAG laser with wavelength of 532nm generated by
A total reflection mirror for reflecting both the higher harmonic wave and the YAG laser fundamental wave having a wavelength of 1064 nm which remains without being converted in the YAG laser second higher harmonic wave generator 2, 30 is a YAG
A wave plate 47 capable of rotating only the polarization plane of the second harmonic of the YAG laser by 90 ° while keeping the polarization plane of the laser fundamental wave as it is.
And a dichroic polarization mirror 31 and an optical path changeover switch including a beam damper 32 capable of blocking the light reflected by the dichroic polarization mirror 31. The dichroic polarization mirror 31 has a YAG laser second reflected by a total reflection mirror 29. The harmonics and the fundamental wave of the YAG laser are incident.

The optical path selector switch 30 reflects both the second harmonic of the YAG laser and the fundamental wave of the YAG laser incident on the dichroic polarization mirror 31 when the reflected light from the dichroic polarization mirror 31 is not blocked by the beam damper 32. , Also the beam damper 32
When the reflected light from the dichroic polarizing mirror 31 is blocked by the YAG laser fundamental wave component of the YAG laser fundamental wave and the second harmonic of the YAG laser incident on the dichroic polarizing mirror 31, the YAG laser fundamental wave component is reflected and the YAG laser fundamental wave component is reflected.
Only the second harmonic component of the laser is transmitted.

Reference numeral 33 is an YA for generating a laser beam (YAG laser third harmonic) having a wavelength of 355 nm from the YAG laser second harmonic reflected by the optical path changeover switch 30 and the YAG laser fundamental wave according to the relationship of the above equation (2).
The G laser third harmonic generator 34 is the YAG laser fundamental wave, the YAG laser second harmonic wave and the YAG laser third harmonic wave which remain without being converted into the third harmonic wave in the YAG laser third harmonic wave generator 33. The YAG laser generated by the generator 33. A dichroic mirror that transmits the fundamental wave component and the second harmonic component of the third harmonic and reflects only the third harmonic component. Reference numeral 35 is a YAG laser reflected by the dichroic mirror 34. A total reflection mirror that reflects the third harmonic, and 36 is a dichroic mirror 3.
A beam damper that blocks the YAG laser fundamental wave and the YAG laser second harmonic wave that have passed through 4, 37 includes a nonlinear optical crystal 38 such as a BBO crystal, a front mirror 39, an end mirror 40, etc., and is reflected by the total reflection mirror 35. From the third harmonic of the YAG laser, 1 / λ ₉ = 1 / λ ₇ + 1 / λ ₈ (4) (λ ₉ : pumping light wave (eg, third harmonic of YAG laser), λ ₇ , λ ₈ : generated light wave ) (Optical parametric oscillation), laser light having a wavelength of 628 nm,
An optical parametric oscillator for generating a laser beam having a wavelength of 817 nm, a reference numeral 46 denotes a laser beam having a wavelength of 628 nm generated by the optical parametric oscillator 37.
It is a Perimbroka prism that separates the laser light of nm and the third harmonic of the YAG laser that has not been converted by the optical parametric oscillator 37.

In the nonlinear optical crystal 38, (4)
If the excitation wavelength λ ₉ in the equation is determined, the generated wavelengths λ ₇ and λ ₈ are automatically determined according to the angle of the crystal.

The operation of this embodiment will be described below.

When obtaining a laser beam with a wavelength of 628 nm, the rotation angle of the wave plate 47 of the optical path changeover switch 30 is set to such an angle that the second harmonic of the YAG laser passing therethrough has the polarization reflected by the dichroic polarization mirror 31. Further, the beam damper 32 is set so as not to block the reflected light from the dichroic polarization mirror 31.

In this state, when the YAG laser oscillator 1 oscillates a YAG laser fundamental wave having a wavelength of 1064 nm, the YAG laser second harmonic generator 2 causes YA
The YAG laser second harmonic with a wavelength of 532 nm is generated from the G laser fundamental wave, and the YAG laser second harmonic and the YAG laser second harmonic generator 2 remain without being converted into the second harmonic in the YAG laser second harmonic generator 2. The wave is reflected by the total reflection mirror 29 and the dichroic polarization mirror 31 and is incident on the YAG laser third harmonic generator 33, and by the YAG laser third harmonic generator 33,
From the YAG laser fundamental wave and the second harmonic of the YAG laser, the YAG having the wavelength of 355 nm is obtained by the relation of the above equation (2).
A laser third harmonic is generated.

The YAG laser third harmonic generated by the YAG laser third harmonic generator 33, and the YAG laser fundamental wave and the YAG laser second harmonic remaining without being converted by the YAG laser third harmonic generator 33. Of these, the fundamental wave component and the second harmonic component pass through the dichroic mirror 34 and are blocked by the beam damper 36.
Only the third harmonic component is reflected by the dichroic mirror 34, and further reflected by the total reflection mirror 35 to enter the optical parametric oscillator 37.

The optical parametric oscillator 37 has a wavelength 355.
When the YAG laser third harmonic of nm enters, laser light of wavelength 628 nm and laser light of wavelength 817 nm are generated from the third harmonic of YAG laser due to the relation of the expression (4), and the laser light of wavelength 628 nm is , The Y of 355 nm wavelength remaining without being converted by the laser light of 817 nm wavelength and the optical parametric oscillator 37.
AG laser third harmonic and Perimbroka prism 19
Separated by.

Further, in the present embodiment, the optical parametric oscillator 37 is rotated from the optical parametric oscillator 37 by rotating the angle of the nonlinear optical crystal 38.
Laser light having an arbitrary wavelength in the wavelength range of 0 nm can be obtained.

On the other hand, in the solid-state wavelength tunable laser device shown in FIG. 2, a titanium sapphire laser second harmonic generator 17 and a titanium sapphire laser third harmonic are generated from the titanium sapphire laser fundamental wave oscillated by the titanium sapphire laser oscillator 9. When the titanium sapphire laser second harmonic, the titanium sapphire laser third harmonic, or the fourth harmonic is generated by the fourth harmonic generator 18, the wave plate 47 in the optical path selector switch 30 is used.
Is set to an angle such that the YAG laser second harmonic passing therethrough has a polarization that passes through the dichroic polarizing mirror 31, so that the YAG laser second harmonic passes through the dichroic polarizing mirror 31. YA
The titanium sapphire laser oscillator 9 is excited by the G laser second harmonic, and the titanium sapphire laser fundamental wave oscillated by the titanium sapphire laser oscillator 9 is made incident on the titanium sapphire laser second harmonic generator 17 to generate the titanium sapphire laser oscillator. The second harmonic of the titanium sapphire laser, and the titanium sapphire laser fundamental wave remaining without being converted into the second harmonic in the titanium sapphire laser second harmonic generator 17 are converted into the titanium sapphire laser. The third harmonic generation / fourth harmonic generator 18 is made incident to generate a titanium sapphire laser third harmonic or fourth harmonic.

At this time, the optical path selector switch 3
The beam damper 32 at 0 is positioned so as to block the YAG laser fundamental wave reflected by the dichroic polarization mirror 31.

The solid-state wavelength tunable laser device of the present invention is not limited to the above-described embodiment, but the titanium sapphire laser oscillators 9 and 24 oscillate by rotating the angles of the wavelength tuning elements 14 and 45. It goes without saying that the wavelength of the titanium sapphire laser fundamental wave can be changed, the oscillation wavelength of the optical parametric oscillator 37 can be changed, and other various changes can be made without departing from the scope of the invention.

[0054]

As described above, in the solid-state wavelength tunable laser device according to claim 1 of the present invention, an optical parametric is generated by the difference frequency generation, and in the solid-state wavelength tunable laser device according to claim 2 of the present invention. By oscillating, it is possible to obtain laser light of any wavelength in the entire range of 205 to 1100 nm including the wavelength range of 550 to 670 nm which cannot be generated in the conventional solid wavelength tunable laser device using titanium sapphire. The excellent effect that the application as a laser device expands can be exhibited.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an embodiment of a solid-state wavelength tunable laser device according to claim 1 of the present invention.

FIG. 2 is a conceptual diagram of an embodiment of a solid-state wavelength tunable laser device according to claim 2 of the present invention.

FIG. 3 is a conceptual diagram of an example of a conventional solid-state wavelength tunable laser device.

[Explanation of symbols]

1 YAG laser oscillator 2 YAG laser 2nd harmonic generator 9 Titanium sapphire laser oscillator 17 Titanium Sapphire Laser Second Harmonic Generator 20 YAG laser second harmonic generator for difference frequency generation 24 Titanium sapphire laser oscillator for difference frequency generation 27 Difference frequency generator 33 YAG Laser Third Harmonic Generator 37 Optical parametric oscillator

Claims (2)

[Claims] 1. A YAG which oscillates a YAG laser fundamental wave.
A laser oscillator 1, a YAG laser second harmonic generator 2 for generating a YAG laser second harmonic from a YAG laser fundamental wave oscillated by the YAG laser oscillator 1, and a YAG laser second harmonic generator 2. A titanium-sapphire laser oscillator 9 that is excited by the generated second harmonic of the YAG laser to oscillate a titanium-sapphire laser fundamental wave, and a titanium-sapphire laser fundamental wave that is oscillated by the titanium-sapphire laser oscillator 9 A titanium sapphire laser second harmonic generator 17 for generating
In the YAG laser second harmonic generator 2, YAG
A YAG laser second harmonic generator 20 for generating a YAG laser second harmonic from a YAG laser fundamental wave component that has not been converted to a laser second harmonic,
A titanium sapphire laser oscillator 24 for generating a difference frequency, which is excited by the second harmonic of the YAG laser generated by the YAG laser second harmonic generator for generating the difference frequency, and oscillates a titanium sapphire laser fundamental wave, and the difference frequency generating Frequency generator for generating difference frequency laser light from the titanium sapphire laser fundamental wave oscillated by the titanium sapphire laser oscillator 24 and the titanium sapphire laser second harmonic wave generated by the titanium sapphire laser second harmonic wave generator 17 27. A solid-state wavelength tunable laser device comprising: 2. A YAG which oscillates a YAG laser fundamental wave.
From a laser oscillator 1, a YAG laser second harmonic generator 2 for generating a YAG laser second harmonic from a YAG laser fundamental wave oscillated by the YAG laser oscillator 1, and a YAG laser second harmonic generator 2. A titanium-sapphire laser oscillator 9 which is excited by the generated second harmonic of the YAG laser and oscillates a titanium-sapphire laser fundamental wave, and a titanium-sapphire laser second harmonic wave generated from the titanium-sapphire laser fundamental wave oscillated by the titanium-sapphire laser oscillator 9. Second harmonic generator 17 for generating titanium sapphire laser, the YAG laser fundamental wave remaining without being converted into the second harmonic in the YAG laser second harmonic generator 2, and Y
YAG generated by the AG laser second harmonic generator 2
YAG laser third harmonic generator 33 for generating YAG laser third harmonic by laser second harmonic
And the optical parametric oscillator 37 for generating optical parametric oscillation laser light by the YAG laser third harmonic generated by the YAG laser third harmonic generator 33. .