JPH03155687A - Semiconductor laser excited solid state laser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ultra-small semiconductor laser-excited solid-state laser device used for recording and reproducing optical discs, laser applied measurement, and the like.

Conventional technology Conventionally, arc lamps, flash lamps, etc. have been used to excite solid-state laser devices, but due to poor excitation efficiency, the overall efficiency of the laser is poor (in terms of heat dissipation of the lamp and laser medium). However, the equipment had to be large.

However, in recent years, with the increase in the output power of semiconductor lasers, attempts have been made to use them as an excitation source for solid-state lasers. By using a semiconductor 1) laser, the wavelength can be matched to the absorption band of a solid-state laser, and the pumping efficiency is very good.Moreover, there is no heat generation due to absorption of excess spectrum, so heat dissipation is easy, and it is small and compact. A highly efficient solid-state laser can be realized.

On the other hand, it has long been known to convert solid-state laser light into harmonics using a nonlinear optical crystal such as a KT i 0PO4 (KTP) crystal to obtain green or blue visible light. Attempts have also been made to utilize harmonics of solid-state laser light.

FIG. 4 shows a configuration diagram of a conventional semiconductor laser pumped Nd:YAG laser. Nd:YAG rod, KTP crystal 2. in the same package. SELFOC lens 4. A semiconductor laser chip 5 is housed therein.

The resonator of the YAG laser is the excitation side view of the YGA rod 1.
-A and the output side end face 2-B of the KTP crystal 2, and the KTP crystal 2 is inserted into this resonator. The semiconductor laser beam is focused onto the end face of the YAG rod by the SELFOC lens 4, and the YAG rod 1
is excited from the axial direction.

Problems to be Solved by the Invention In the method shown in Figure 2, in which a nonlinear optical crystal is inserted into a resonator for the fundamental wave to convert it into a second harmonic, Since there is an axial mode and its sum frequency is generated within the nonlinear optical crystal, the second harmonic is strongly modulated and causes noise.This is a big problem especially when using this second harmonic for optical discs. It becomes.

Means for Solving the Problems In order to reduce the noise of the second harmonic due to the sum frequency, the semiconductor laser pumped solid-state laser device of the present invention includes a KTP crystal, a λ/4 plate (λ-1.064 μm), a Nd: YAG
The rod, SELFOC lens, and semiconductor laser chip are housed in the same package in this order.

Function The above configuration makes it possible to realize an integrated, ultra-compact, low-noise green laser.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 shows a structural diagram of a semiconductor laser pumped solid-state laser device of the present invention. KTP crystal 2. in the same package. λ/4 plate 3 × λ1.064 μm), Nd: Y
AG rod 1. SELFOC lens 4. The semiconductor laser chips 5 are housed in this order. The YAG rod 1 has a Nd concentration of 131%, a diameter of 3 mm, and a length of 5 mm. λ/4 plate 3 has a width of 3 x 3 and a length of 5. KTP crystal 2 has a width of 3 x 3.

It is 5m long. The resonator is formed between the excitation side end face 1-A of the YAG rod 1 and the output side end face 2-B of the KTP crystal 2, the former being a convex mirror with a radius of curvature of 60 days, and the latter being a flat mirror. . KTP crystal 2 is Nd:
Since the structure is such that it is inserted into the resonator of the YAG laser, and the beam waist is within the KTP crystal 2, conversion to harmonics is performed efficiently. YAG rod 1, λ/4 plate 3. The reflective film coating for each wavelength on each side of the KTP crystal 2 is as shown in Table 1.

Table 1 Furthermore, a semiconductor laser chip 4 with a wavelength of 0.809 μm is used for excitation, and the YAG rod 1 is axially excited by condensing the light with a SELFOC lens 4.

KTP crystal 2 uses TYPEH phase matching, and λ
The axial direction of the /4 plate 3 forms an angle of 45 degrees with the direction of ordinary waves and extraordinary waves of the KTP crystal 2. When the λ/4 plate 3 is inserted in Fig. 2 (Fig. 2 (a)) and when not (Fig. 2 (b)
)) shows a diagram tracing the power change of harmonic 0.53 μm. As can be seen from this figure, inserting the λ/4 plate reduces noise and stabilizes the output of harmonics of 0.53 μm. Figure 3 shows the input/output characteristics when a λ/4 plate is inserted. When the driving current of the semiconductor laser was 400 mA, an output of 16 mW and harmonics of 0.53 μm was obtained.

ADVANTAGEOUS EFFECTS OF THE INVENTION The semiconductor laser-excited solid-state one-noser device of the present invention is an ultra-compact solid-state laser harmonic laser with low noise output, and can be used for recording and reproducing optical discs and one-noser printer.

It has a great effect on laser applied measurements, etc.

[Brief explanation of the drawing]

Fig. 1 is a structural diagram of the semiconductor laser pumped solid-state laser device of the present invention, and Fig. 2 (a) and (b) show the time reduction of the output of the laser device of the present invention and the time change of the output of the laser device of the conventional structure. FIG. 3 is a diagram showing the harmonic output of 0.53 μm with respect to the drive current of the present invention, and FIG. 4 is a structural diagram of a conventional semiconductor laser pumped solid-state laser device. 1...Nd: YAG rod, 2...
・KTP crystal, 3...λ/4 plate, 4...
・Self-on lens, 5... Semiconductor packaged laser chip, 6... PIN photodiode, 7
······base.

Claims (1)

[Claims] A nonlinear optical crystal, a λ/4 plate, a solid laser medium, a lens, and a semiconductor laser chip are housed in this order in the same package. An optical resonator is formed with the far end face of the semiconductor laser chip, the λ/4 plate and the nonlinear optical crystal are inserted into the resonator, and the semiconductor laser is A semiconductor laser-pumped solid-state laser device, characterized in that the solid-state laser medium is end-excited in the axial direction by condensing light.