JPH04119678A - Laser amplifier - Google Patents

Abstract

PURPOSE:To enable a laser beam to be protected against loss and prevented from changing in optical axis by a method wherein an oscillator which oscillates a laser beam, an amplifier, and a measuring system which monitors the laser beam incident on the amplifier are provided. CONSTITUTION:In a laser amplifying device, an oscillator 2 provided with resonators 1A and 1B oscillates a laser beam, and the laser beam is made to impinge on an amplifier 4 as an incident beam 3. The amplifier 4 amplifies the incident beam 3 and outputs an outgoing beam 5. A measuring system 14 is provided to monitor the incident beam 3. That is, the amplifier 4 is provided with an incident window 15 inclined to make a certain angle with a plane vertical to a laser ray axis, the reflected light from the window 15 is inputted into the measuring system 14 as a sample light, and the sample light is made to impinge on a photo electric tube 18 and a laser output meter 19 through a beam distributing mirror 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a laser amplification device, and more particularly to a laser amplification device that is designed to achieve higher efficiency and easier maintenance.

(Conventional technology) Laser amplification devices are used in material cutting, optical communications, medical technology,
It is used in a wide range of fields such as the nuclear industry. In particular, in the nuclear power industry, it has been applied as an atomic laser uranium enrichment technology using a high-power copper vapor laser, and research and development is underway to create a laser system with low loss and high efficiency.

When using high-power lasers such as atomic laser uranium enrichment technology in the nuclear industry, where losses in optical elements greatly affect the overall system output,
It is important to use optical elements (for example, lenses, mirrors, etc.) that have as little loss as possible, and to reduce the number of optical elements by devising the structure.

As shown in FIG. 4, a conventional laser amplification device includes an oscillator 2 having resonators IA and IB, and a laser beam oscillated from the laser oscillator 2 is input to an amplifier 4 as an incident beam 3. The amplifier 4 amplifies the incident beam 3 and extracts it as an emitted beam 5.

Although only one amplifier 4 is shown in FIG. 4, a multi-stage amplification configuration including multiple amplifiers 4 may be adopted.
, 6B are connected to these laser driving power supplies CA, 6B.
is controlled by a power supply control device 7.

The laser amplification device is equipped with a measurement system unit 8 that monitors the incident beam 3 that enters the amplifier 4 in order to optimize the power supply conditions of the amplifier 4 for the oscillator 2 and drive timing conditions (in the case of a pulsed laser). The measurement system 8 receives several % of the incident beam 3 from the oscillator 2 to the beam spreader 4.
Beam distribution mirror 10 that takes in the sump/L light 9 of
A is provided, and the sample light 9 is sent to a phototube (pulse waveform measuring device) 1 by another beam distribution mirror 10B.
1 and a laser output meter 12. These phototube 11 and laser output meter 121Z8 power signals are input to the power supply control device 7, and the laser drive power supplies 6A, 6B
This feedback is used to optimize the electrical conditions and drive timing conditions.

(Problem to be Solved by the Invention) The conventional laser amplification device has an optical fiber between the oscillator 2 and the amplifier 4, or between the amplifier 4 and an amplifier (not shown) when a plurality of amplifiers 4 are installed. A beam distribution mirror 10A as an element is installed. The laser loss caused by the beam distribution mirror 10A increases as the laser intensity increases, and has a negative effect on the efficiency of the entire system. For this reason, attempts have been made to apply an anti-reflection coating to the surface of the beam distribution mirror 10A so that the reflectance is as small as possible, but it is still difficult to reduce the reflectance to 1% or less. Further, if the beam distribution mirror 10A is installed between the oscillator 2 and the amplifier 4, it causes the optical axis of the laser beam to shift, and there is a problem that the time and labor required for adjusting the optical axis increases.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a laser amplification device that can prevent loss of the laser beam and movement of the optical axis, and can improve efficiency and maintainability. shall be.

[Structure of the invention]

(Means for Solving the Problems) The present invention includes an oscillator that oscillates a laser beam, an amplifier that amplifies the laser beam from the oscillator, and a measurement system that monitors the laser beam incident on the amplifier. The amplifier is provided with an entrance window tilted with respect to the laser optical axis, and the measurement system monitors the laser beam using reflected light from the entrance window.

(Function) Since the measurement system monitors the laser beam using the reflected light from the incident window provided in the amplifier at an angle with respect to the laser optical axis, there is no conventional beam separation between the oscillator and the amplifier. There is no need to provide a distribution mirror. Therefore, loss of the laser beam and movement of the optical axis due to the beam distribution mirror can be prevented, and efficiency and maintainability can be improved.

(Example) Embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a laser amplification device according to the present invention, in which a laser beam is oscillated from an oscillator 2 having resonators IA and IB, and this laser beam is input to an amplifier 4 as an incident beam 3. .

The amplifier 4 receives and amplifies the incident beam 3 and outputs it as an emitted beam 5. Although only one amplifier 4 is shown in FIG. 1, two or more amplifiers 4 may be installed. In this case, the exit beam 5 becomes the input beam of the next amplifier (not shown). Amplifier 4 and oscillator 2
are connected to laser drive power supplies 6A and 6B, respectively.
These laser driving power supplies 6A and 6B are controlled by a power supply control device 7.

The laser amplification device is equipped with a measurement system 14 for monitoring the incident beam 3 in order to optimize the power supply conditions of the amplifier 4 for the oscillator 2 and, in the case of a pulsed laser, the drive timing conditions.

That is, the amplifier 4 is provided with an entrance window 15 having a predetermined inclination (for example, several degrees) with respect to a plane perpendicular to the laser optical axis of the input beam 3.
The reflected light is taken into the measurement system 14 as sample light 16, and is incident on a phototube (pulse waveform measuring device) 18 and a laser output meter 19 via a beam distribution mirror 17. These 18 phototubes and 8 lasers total 1
The intensity of the laser beam measured in step 9 and the timing signal are sent to each laser driving power source 6A via a power source control device 7.

The intensity and stability of the emitted beam 5 of the amplifier 4 are ensured by feeding back to the amplifier 6B and optimizing the electrical input and timing.

Note that when a plurality of amplifiers 4 are provided, the output beam 5 of the amplifier 4 becomes the input beam of the next amplifier, and therefore, the input beam is similarly monitored by a measurement system (not shown).

In this manner, according to the above embodiment, the reflected light from the entrance window 15 provided in the amplifier 4 is taken into the phototube 18 and the laser output meter 19 as the sample light 16.
There is no need to install the beam distribution mirror 10A between the oscillator 2 and the amplifier 4 as in the conventional case. Therefore, loss of the laser beam due to the beam distribution mirror 10A is prevented,
Stable amplified laser output can be obtained by increasing efficiency. Furthermore, since the beam distribution mirror 10A is not provided, it is possible to prevent the optical axis of the laser beam from shifting, making it easier to adjust the optical axis and improving maintainability.

2(A) and 2(B) show another embodiment of the present invention, in which a bellows is attached to the head part A of the oscillation tube 21 of the amplifier 4, as shown in an enlarged view in FIG. 2(B). The window 24 is attached via the angle adjustment bar 22 and the angle adjustment bar 23, and the angle θ between the surface of the window 24 and the plane perpendicular to the optical axis B is adjusted.
is adjustable. This makes it possible to accurately align the emission direction of the reflected component on the surface of the window 24 with the direction of the installed measurement system 14.

FIG. 3 shows still another embodiment of the present invention, in which the oscillation tube 21A of the amplifier 4 is housed in a protective cover 25, and an incident beam hole 26 through which the incident beam 3 passes through the protective cover 25; A sample light extraction hole 27 through which the sample light 16 passes and an exit beam hole 28 through which the exit beam 5 passes are provided. In this example, measurement system 1
4 is installed outside the protective cover 25, and it is possible to reduce noise components from sources other than the laser amplification device.

〔Effect of the invention〕

In the laser amplification device according to the present invention, since the measurement system monitors the laser beam using the reflected light from the incident window provided in the amplifier at an angle with respect to the laser optical axis, there is a gap between the oscillator and the amplifier. There is no need to provide an optical element as in the conventional case. Therefore, loss of the laser beam due to the optical element can be prevented, and laser output can be highly efficient and stabilized. Furthermore, since there is no need to provide an optical element between the oscillator and the amplifier, it is possible to prevent the optical axis of the laser beam from shifting, and the optical axis can be easily adjusted, improving maintainability.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of a laser amplification device according to the present invention, FIG. 2 (A) is a block diagram showing an oscillation tube in another embodiment of the present invention, and FIG. 2(A) is a block diagram showing an enlarged view of the head section, FIG. 3 is a block diagram showing still another embodiment of the present invention, and FIG. 4 is a block diagram showing a conventional laser amplification device. 2... Oscillator, 3... Incident beam, 4... Amplifier, 5... Emission beam, 6A, 6B... Laser drive power supply, 7... Power supply control device, 14... Measurement System, 1
5...Incidence window, 16...Sample light, 17
...Beam distribution mirror, 18...Phototube, 19...
・Laser output meter. Applicant's agent Hisashi Hatano Figure fA Figure Figure fA

Claims (1)

[Claims] The amplifier includes an oscillator that oscillates a laser beam, an amplifier that amplifies the laser beam from the oscillator, and a measurement system that monitors the laser beam incident on the amplifier. A laser amplification device comprising: a laser amplification device, wherein the measurement system monitors a laser beam using reflected light from an incident window of the measurement system.