JPH0414280A - Raman laser device - Google Patents

Abstract

PURPOSE:To improve the overall efficiency of a Raman laser system by reusing CO2 Raman laser light outputted form a Raman laser device without Raman transformation as the excitation light of a Raman laser. CONSTITUTION:Outputted 10.6mum light is separated by means of a 10mum/16mum separator 5 and the separated light is reinjected into a TEA CO2 laser amplifier 2 at the repetitive frequency through an optical delay 6 for amplification. As a result, the 10.6mum light exceeds the threshold of Raman transformation and is reinjected to a Raman laser device 3 as the excitation light of the device 3. Since the 10.6mum light which has been passed through the Raman laser device as a loss without Raman transformation is reutilized as the excitation light, it is required to the TEA CO2 laser oscillator 1 of this Raman laser device to output the first one pulse only and the energy to the oscillator becomes unnecessary, resulting in a high energy efficiency. Moreover, since the turning of the oscillator can be completed at the time of the first one pulse, control of turning can be made by a simple method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a Raman laser device that uses a CO2 laser as excitation light and is used for isotope separation and the like.

(Prior Art) A CO2 laser pumped Raman laser system is a high-power laser system that converts the wavelength of 10.6 μs of CO2 laser light into 16 Is using stimulated Raman scattering. It is described in detail in ``Co2 Laser Excited Infrared Hydrogen Raman Laser '86 Laser Application Technology Symposium Proceedings''.

The oscillation efficiency of a Raman laser is the output of excitation light.

In order to induce wavelength conversion by stimulated Raman scattering, the output of the CO2 laser, which is the excitation light, must be increased to a threshold value that efficiently induces stimulated Raman scattering. It is necessary to oscillate in longitudinal mode. For this reason, the CO2 laser, which is the pumping light, is composed of an oscillator and a multistage amplifier in order to raise its output to the oscillation threshold of the Raman laser.Furthermore, in order to always obtain a single longitudinal mode, the oscillator is , a tuning control device is required.

FIG. 3 shows the configuration of a conventional CO2-excited Raman laser system. In this figure, 1 is TEA
CO□ laser oscillator, 2 is a TEAC○2 laser amplifier, 3 is a Raman laser device, 4 is a tuning control device for obtaining a single longitudinal mode, which is described here as an example of injection locking method, and 41 is a large-scale A CWC○2 laser oscillator for synchronization, 42 is a mirror.

The operation of this method is as follows. cwco for injection locking
The 2 laser oscillator 41 has previously oscillated in a single longitudinal mode, and this light is injected into the TEA CO2 laser oscillator 1 by a mirror 42, and at the same time it is tuned to the TEAC○2 laser oscillator 1. As a result, the TEA CO2 laser oscillator 1 oscillates in a single longitudinal mode. TEA C
Since it is extremely difficult to obtain an output up to the oscillation threshold of the Raman laser device 3 using only the O2 laser oscillator 1, the output is amplified by a multi-stage amplifier 2 to increase the threshold of the Raman laser device 3. Get more laser power.

When the CO□ Rayleigh light exceeding the threshold value is input to the Raman laser device 3, the wavelength of the CO2 laser light is shifted to 16 μs by Raman conversion.

Output.

(Problems to be Solved by the Invention) The conventional C*2 laser excitation Raman laser system having the above-described configuration has the following problems.

That is, the Raman laser device 3 does not perform Raman conversion when the excitation light does not exceed the threshold value, but
Even if excitation light exceeding the threshold value is incident, not all of the excitation light is Raman converted and becomes 16 μm light, but 16 μs light is output based on a certain conversion efficiency. The 10.6 tm excitation light that has not been subjected to Raman conversion is output from the Raman laser device 3 as it is. as a result,
This 10.6 μs light becomes a loss in the Raman laser system.

The present invention was made to solve the above problems, and its purpose is to reuse CO2 laser light, which has not been Raman converted and was treated as a loss, as excitation light, thereby increasing the overall efficiency of the Raman laser system. The purpose is to increase

[Structure of the invention]

(Means for Solving the Problems) The Raman laser device of the present invention provides a
0.6. T emitted from a Raman laser device as light
The EA CO2 laser beam is again incident on the TEACO2 laser amplifier 2, amplified again to the threshold of the Raman laser device, and reused as excitation light for the Raman laser device.

(Operation) By the above means, C that was not converted into Raman and was lost
Since the O2 laser light can be reused as the excitation light of the Raman laser device 3, the overall efficiency of the Raman laser system can be increased.Furthermore, the mode of the excitation light can be changed to a single longitudinal mode for only the first pulse. Once oscillated, the light can be used forever, eliminating the need for complex tuning control.

(Example) The configuration of an example of the present invention will be described below with reference to the drawings. FIG. 1 shows a system for increasing the efficiency of a Raman laser device according to an embodiment of the present invention. Components common to those in FIG. 3 are given the same reference numerals, and their explanations are omitted.

As shown in the figure, in the configuration of this embodiment,
Conventional Raman laser system with 10 μm/16 ρ separator5. It has a configuration in which an optical delay 6 and an excitation light re-injection mirror 7 are added.

The operation of the above configuration will be explained.

The TEA CO2 laser oscillator 1 outputs a single longitudinal mode optical pulse under the action of the tuning control device 4, and the light is amplified by the TEA CO2 laser amplifier 2.
The light output exceeds the threshold at which Raman conversion occurs. This light becomes excitation light for the Raman laser device 3, and the Raman laser device 3 outputs 16 μs light with a certain conversion efficiency. At this time, the excitation light that has not been Raman converted within the Raman laser device is output as 10.6Ia light as is. This 10.6p light is a system loss.

In the Raman laser device high efficiency system of this embodiment, 10. ca/10.6 with 5 outputs by 15 side separator 5
T! m light is separated and this light is transmitted to the TE via optical delay 6.
A Go□Inject according to the repetition frequency of the laser amplifier 2 (for example, when the repetition frequency is 5 KPPS,
After a delay of 200 A1s, the light is injected into the amplifier) and amplified again. As a result, the 10.6 μs light exceeds the Raman conversion threshold and is again injected as excitation light to the Raman laser device 3.

As described above, in the configuration of the present invention, the 10.6 μs light that was transmitted through the Raman laser device as a loss without being subjected to Raman conversion can be used as excitation light again, so the TEA CO2 laser oscillator Since only the first pulse needs to be output, the energy required for the oscillator is no longer required, resulting in very high energy efficiency. Further, since the oscillator needs to be tuned only with the first pulse, tuning control can be performed in a simple manner.

In this embodiment, the amplifier is re-injected into the amplifier of the same series, but if the repetition frequency is low, there is also a method of injecting into the amplifier 8 of another series, as shown in FIG. In this case, the oscillator 1 needs to be operated continuously.

〔Effect of the invention〕

As described above, according to the present invention, the lost 10.6 habit light is amplified again and used as excitation light for the Raman laser device, so the oscillator only needs to output the first pulse. , the efficiency of the system increases.

Furthermore, since it is sufficient to tune one oscillator using only the first pulse, tuning control can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a Raman laser device according to an embodiment of the present invention, FIG. 2 is a block diagram of a Raman laser device according to another embodiment of the present invention, and FIG. 3 is a block diagram of a conventional Raman laser device. be. 1...TEA CO□Laser oscillator 2.8・TEA
CO2L/- laser amplifier 3... Raman laser device 4... Tuning control device 41... Injection locking cw c
o, laser oscillator 42...mirror 5...
・10μ5716μs Separator 6...Optical delay 7・
...Excitation light re-injection mirror 8...Amplifier agent Patent attorney Noriyuki Chika

Claims (1)

[Claims] A Raman laser device that uses a CO_2 laser as excitation light, characterized in that the CO_2 laser light output from the Raman laser device without being subjected to Raman conversion is used again as the excitation light of the Raman laser.