JPH0832165A - Variable-wavelength/self-harmonic laser medium - Google Patents

Abstract

PURPOSE:To enable a laser medium to oscillate variable-wavelength laser or self-harmonic laser by using a Cr-doped YAB crystal or YGAB crystal added with Cr and Ga. CONSTITUTION:A Cr<3+>:YAB single crystal is grown from 99.9-% pure Y2O3, Al2O3, Cr2O3, B3O3, K2CO3, and MoO3 by using the top seed solution method. The synthesization is performed based on a reaction formula, Y2O3(1-x)Al2O3 +xCr2O3+4B2O3 2Y(Al1-xCrx)3(BO2)4K2CO3 +3MoO3 K2Mo3O10+CO2 (where, x=0.005) by dropping the temperature from the saturation point of about 1050 deg.C to 990 deg.C at the rate of 0-2 deg.C/day. Therefore, a laser medium which can oscillate laser in a wide band range from red color to near red color in a variable-wavelength state and can generate ultraviolet laser light by self-generating harmonics can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength tunable / self-harmonic laser medium. For more information,
The present invention relates to a wavelength tunable / self-harmonic laser medium particularly useful as a wavelength tunable light source for spectroscopy, optical information processing, and a medical laser light source.

[0002]

2. Description of the Related Art Conventionally, Nd: YAB (Nd _X Y _1-X Al ₃ (B0 ₃ )) obtained by doping a YAB crystal with Nd is conventionally used.
₄ ) The crystal is known as a so-called multifunctional crystal that has two functions of laser oscillation and wavelength conversion. The laser obtained using this crystal is 531 nm green light. On the other hand, in recent years, it has been required to realize a laser having a shorter wavelength than this, and therefore, Cr is used instead of Nd.
The development of laser media doped with ³⁺ has been considered.

However, the growth of a good quality Cr ³⁺ : YAB single crystal is quite difficult at present because of the fact that Cr cannot be uniformly doped and growth fringes occur.
Nurturing technology has not been established in practice. Further, it has been conventionally known that a Cr ³⁺ : YAB (Yttrium Aluminum Borate) crystal has fluorescence, but evaluation of optical characteristics as a laser medium has hardly been made,
Practical utility has not been specifically examined.

The present invention has been made in view of the circumstances as described above, and Cr-doped Y, which has a great interest in its optical characteristics as well as the realization of a shorter wavelength laser.
The purpose of the present invention is to provide a new utilization method for the AB crystal and its approximate crystal.

[0005]

In order to solve the above problems, the present invention provides a wavelength tunable / self-harmonic laser medium made of Cr-doped YAB crystal or YGAB crystal.

[0006]

In the present invention, the crystal of YGAB doped with Cr-doped YAB or Ga as described above is used for tunable laser or self-harmonic laser oscillation. As a result, according to the present invention, the laser oscillation can be tuned in a wide range from red to near infrared, and the second harmonic can be generated simultaneously with the laser oscillation with one crystal material. To be done.

The present invention will be described in more detail with reference to the following examples.

[0008]

Example 1 In this example, a Cr ³⁺ : YAB single crystal was mixed with K ₂ M.
It was grown by the top seed solution method using o ₃ O ₁₀ flux. The furnace is a resistance heating type cylindrical furnace, and the accuracy of the controller is 1 ° C. The crucible is made of platinum 50φ x 65
The one of [mm ³ ] was used. Raw materials are Y ₂ O ₃ and Al ₂ O
₃ , Cr ₂ O ₃ , B ₃ O ₃ , K ₂ CO ₃ , and MoO ₃ having a purity of 99.9% were used.

The synthesis of Cr: YAB and K ₂ Mo ₃ O ₁₀ was carried out by the following reaction formula.

[0010]

Embedded image

In this embodiment, x = 0.005, and 0 to 2 ° C./day from the saturation point of about 1050 ° C. is 99.
The temperature was lowered to 0 ° C. The crystal growing period is 42 days.
The fluorescence spectrum and the fluorescence lifetime and absorption spectrum of this crystal were measured by a spectrophotometer (Nippon Bunko Kogyo SS-25 high-resolution fluorescence spectrometer and Shimadzu spectrophotometer UV-3100).
S) was used for the measurement.

FIG. 1 shows an absorption spectrum. From FIG. 1, it can be seen that there is broad absorption in the 420 nm band and the 600 nm band, and the transparent region around 350 nm is transparent. FIG. 2 shows the fluorescence spectrum. The two peaks at about 560 nm to 600 nm are the spectrum of the excitation light. It can be seen that there is broad fluorescence over about 640 nm to 860 nm and there is a fluorescence peak at about 710 nm to 740 nm. Fluorescence lifetime is 170 μsec
Met. In addition, the induction discharge cross section is 1.3 × 10 ^-19
cm ^2, and was found to be greater than the Cr-based laser such as another CrLiSAF.

Further, when 720 nm of a titanium sapphire laser was incident on this crystal, SHG
(360 nm) was confirmed. From this result, it is understood that this crystal has no absorption around 350 nm, and thus it is possible to generate the ultraviolet light by the laser oscillation in the above wavelength band and the self-doubling. These crystals are 700n
If laser oscillation is performed in the m band, it is possible to obtain a 350 nm band ultraviolet laser beam by SHG (second harmonic generation) with a single element.

When the optical amplification factor was measured using a crystal having a thickness of 2.5 mm, a gain of about twice was obtained near the wavelength of 820 nm, and laser oscillation was possible with the wavelength variable in the range of 700 to 900 nm. The sex was confirmed. FIG. 3 shows the measurement result of the single path gain at this time. Example 2 As in Example 1, C containing 0.2% of Cr and 25% of Ga
A r ³⁺ : YGAB crystal was grown. It was grown at 995.8 ° C. for 16 days.

FIG. 4 shows the resulting absorption spectrum, and FIG. 5 shows the fluorescence spectrum. Cr ^3+: If YGAB crystals, Cr ^3+: YAB crystal similar properties cr ^3+: than when YAB crystals was found that further seen in the long wavelength side.

[0016]

As described in detail above, according to the present invention, it is possible to oscillate wavelength tunably in a wide range from red to near red,
Furthermore, a laser medium that can also generate ultraviolet laser light by self-harmonic generation is realized.

[Brief description of drawings]

FIG. 1 is an absorption spectrum diagram of a Cr: YAB crystal in an example of the present invention.

FIG. 2 is a fluorescence spectrum diagram of a Cr: YAB crystal corresponding to FIG.

FIG. 3 is an absorption spectrum diagram of a Cr: YGAB crystal in another example.

FIG. 4 is a measurement diagram of a gain during a single pass.

5 is a fluorescence spectrum diagram of a Cr: YGAB crystal corresponding to FIG.

Claims (3)

[Claims] 1. Cr-doped YAB crystal or Y
Tunable / self-harmonic laser medium made of GAB crystal. 2. The laser medium according to claim 1, which oscillates a wavelength tunable laser in the red to near infrared region. 3. The laser medium according to claim 1, wherein blue or ultraviolet laser light is generated by self-harmonic generation.