JPS5839083A - Passive mode synchronous glass laser oscillator - Google Patents

Abstract

PURPOSE:To stabilize an oscillation of a laser oscillator by inserting an etalon into a resonant. CONSTITUTION:When a laser oscillator is excited by a lamp, energy is stored in a glass rod 5. Light is reflected via a mirror 1 and a mirror 2 to reciprocate in a resonant, is amplified whenever the light passes the rod 5, thereby becoming a high intensity light. A saturable absorber 3 initially has an absorbance of the prescribed value, and when the growing degree of the light is suppressed and light transmission intensity is large, the transmission factor becomes large. Many pulses exist in a resonator, but the light is strengthened more at the larger pulse whenever the light passes through the absorber 3, thereby growing to single strong short pulse. A slit 4 limits the diameter of a laser beam, and the operation of the laser is stabilized via an etalon 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a passive mode-locked glass laser oscillator in which the output of a single laser beam is stabilized by inserting an etalon into the resonator.

Glass laser oscillators are used to obtain high output and short pulses, but they have problems with low oscillation probability and large variations in oscillation intensity, and require high oscillation technology and skill.
Compared to AG lasers and the like, their widespread use has been hindered. .

It has been reported that an acousto-optic modulator is inserted into the resonator as an attempt to eliminate and stabilize the variation in the oscillation intensity, but these are expensive and their adjustment requires great care and skill. However, stability over time is also a problem, and it cannot be said to be a low-friction, simple method.

This invention was made in view of the above points.

A stable passive mode-locked glass-laser oscillator can be obtained with an extremely simple and inexpensive configuration that only requires an etalon to be inserted into the resonator. The present invention will be explained below regarding the color plane.

FIG. 1 shows a Nd Niglass laser oscillator showing one embodiment of the present invention. In this figure, 1 is a 100% reflective mirror, 2 is a reflective mirror that transmits part of the light, and both mirrors 1
．． 2 constitutes a resonator.

3 is a saturable absorber such as a saturated dye, 4 is a slit,
5 is a glass rod, and 6 is an etalon.

Etalon 6 has two planes with high plane precision, the spacing between them is several μm to several mm, and they are made parallel with high axiality.

This itself is well known and has conventionally been used as a high-precision spectrometer. Next, the operation of the embodiment shown in FIG. 1 will be explained.

Energy is stored in the glass rod 5 when excited by the lamp. The light is reflected by mirrors 1 and 2 and travels back and forth within the resonator, but each time it passes through the glass rod 5 it is amplified and gradually becomes a stronger source.

The saturable absorber 3 initially has a certain degree of absorption rate and suppresses the degree of light growth. The transmittance of the saturable absorber 3 increases when the transmitted light intensity increases.

Initially, there are many pulses in the resonator, but each time it passes through the saturable absorber 31, the largest pulse becomes more emphasized, and finally a single intense short pulse grows. Set the diameter of the laser beam to IJ. The etalon 6 stabilizes the operation of the laser.

Next, the results of the experiment will be explained.

Mirror 1 is a 100% reflective plane mirror.

Further, as the mirror 2, a plane mirror with 70% reflection was used, and the mirrors 5 and 5 were opposed to each other with an interval of 65 am to form a resonator. The glass rod 5 has a diameter of 4 mm and a length of 75
mm, manufactured by Hoya Glass Co., Ltd. under the trade name rLHG8J, and excited with a Kr flash lamp. The Kr7 lash lamp was used in a simmer mode (a small current was constantly flowing) of several tens of mA. Fluctuation in luminescence amount is ±0.5%
Met. The repetition rate was 1 ppS, the excitation width was 500 μs, and the threshold value for normal oscillation was 35 J.

The output/< pulse train was received by a biplanar, guided to an oscilloscope, and the stability of mode locking was observed.

FIG. 2 is an output waveform diagram of oscillation according to the above experiment, and FIG. 3 is an output waveform diagram when the etalon 6 is removed in the above case.

The envelope waveform shown in Figure 3 was unstable and the probability of such oscillation was low, but with the invention shown in Figure 2, the envelope waveform is stable and the oscillation probability is almost 100%. Became.

In this case, FIG. 4 shows the distribution of 100 shots of the peak value of the 5-oscillation pulse train. As shown in Figure 4, 100
Oscillations were confirmed at the 5th and 98th points F, of which 9
6 shots were within ±15%). This performance is comparable to that of a YAG laser oscillator, which is said to be stable.

As explained in detail above, this invention aims to stabilize the oscillation by inserting an etalon into the resonator, so although it has an extremely simple configuration, it is possible to stabilize the oscillation sufficiently. It has the advantage of

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an embodiment of the present invention, Fig. 2 is an output waveform diagram when an experiment is performed using the passive mode-locked glass φ laser oscillation circuit according to the invention, and Fig. 3 is an experiment shown in Fig. 2. FIG. 4 is a diagram of the output waveform when no etalon is inserted, and FIG. 4 is a distribution diagram of the peak value of the pulse train in the experiment of FIG. In the figure, 1.2 is a mirror, 3 is a saturable absorber, 4 is a slit, 5 is a glass rod, and 6 is an etalon.

Claims (1)

[Claims] 1. A passive mode-locked glass laser oscillator comprising a laser oscillation circuit including a glass rod and a saturable absorber disposed within a resonator, wherein an etalon for stabilizing oscillation is inserted within the resonator.