DE1954767A1 - Method and arrangement for power stabilization of infrared gas lasers - Google Patents

Description

Messerßchmitt-BcJlkow-Blohm GmbH

...., October 28, 1969

Munich

EM 3IO3 '
Kre / sp

Method and arrangement for power stabilization of infrared gas lasers

The invention relates to a method and an arrangement for power stabilization of infrared gas lasers, especially for infrared high-power gas lasers.

So far, the power of such lasers has only been achieved through stabilization the supplied gas and energy quantities regulated or kept constant.

Other methods and arrangements can be found in the output beam a constant fraction of the power, measure it and then influence a control loop that controls the power holds or readjusts a constant value. The first-mentioned method does not contain a control loop and can therefore be used from internal fluctuations in the laser resonator larger fluctuations in power - up to 50? the radiation has to be decoupled for regulation and is thus lost for other purposes. The effective output power is also reduced as a result. Furthermore, the detectors are necessary for rapid regulation according to this aforementioned arrangement are necessary, very expensive and also have to be cooled with liquid nitrogen or helium.

109819/1667 ORIGINAL BATHROOM

EM 3103 _o October 28, 1969

Kre / sp

The invention has set itself the task of eliminating these disadvantages and of creating a method with an arrangement which allows the output power of an infrared gas laeers to be stabilized with simple means. This object is achieved in that the intensity of an im. optical or near infrared range of a gas actively involved in the W laser process - for example, in the case of a CO ₂ laser, the nitrogen in the laser path is measured and this measurement signal is used to control the current and voltage data of the electrical pump system.

To carry out this process, it is proposed that in the A monochromator with a photodiode is arranged in the area of the light of the side lines of the active laser gas in the resonator is associated with an amplifier and a comparator, the output signal of which is an actuator for the power supply of the laser resonator. It is also proposed that a photomultiplier be used as an uncooled, high-time-resolution detector is used.

The advantages of this measure according to the invention are therein too see that worked with the known optics and with very low cost and material expenditure on the detector side and, moreover, the detector system no longer requires cooling. What is essential, however, is that the intensity is more definite Lateral lines - for example with the CO laser the

109819/1667
BAD ORIGiKlXC

EM 3103 ■, ■ 28 ·. October 1969

Krfi / sp,

Transitions of the first and second positive system of stem substance in the range 3300 to 8000 S - represents a measure for the change in the concentration of the laser levels, whereby this intensity in turn is a measure for the laser output which occurs a short time later (for example milliseconds). 1performance is. This allows you to control measures against, changing power take already-before entering this now foreseeable changes, such as, for changes in the current and voltage values ladungj the Pumpent- This is a very significant advantage over the above-described arrangements of the prior Technology in which a ^ part of the effective output power is decoupled and measured and can only then be used for regulation.

The invention is described below and shown schematically in a block diagram, so that further Advantages and measures can be taken.

The arrangement according to the invention is composed as follows in terms of structure and mode of operation: In addition to the laser resonator section 10 with the electrodes 11, 12 there is a monochromator 20 for masking a certain side line of the light tk * emerging from the side of the resonator 10. This side line falls on an intensity measuring arrangement 3Q - for example photodiode or photomultiplier - in which the intensity of the light is converted into an electrical measured value (voltage or current). This measured value is in an amplifier 40

109819 / 1ee?

BATH ORIGINAL.

^{EM 31} ° ³ October 28, 1969

Kre / sp "- 4 - ._ '"

amplified and compared in a comparator 50 rait an adjustable value. The difference output signal 51 of the comparator 50 acts on an actuator 60 _t which changes the energy pollution 70 'of the laser resonator 10 until the measured value difference in the comparator 50 has fallen below a certain device-related limit - for example a noise signal. By changing the adjustable value (voltage or current) in the comparator 50, the output power of the laser can also be changed in a certain range.

/ 5

109819/1667
BAD ORfGiNAL

Claims (3)

EM 3103 28 _v October 1969 Claims (!. 'Process to stabilize the power of infrared gas lasers, preferably CO ^ gas lasers, thereby marking g e t that by means of detectors, for example photomultiplier or semiconductor diodes, the Intensity of a side line lying in the optical or near infrared range of someone actively involved in the laser process Gas, for example the nitrogen in the laser path in COp lasers, is measured and this measurement signal is used to control the current and voltage data of the electrical pump system. 2. Arrangement for performing the method according to claim 1 »characterized g ekennz ei chne t that riser in the area of light (lk) of the side lines of the active Lasergasee int resonator (10) a monochromator (20) with a photodiode (30) is arranged , to which an amplifier (40) and a comparator (5Q) is assigned, the output signal of which influences an actuator (60) for the energy supply (70) of the laser resonator (10). 3. Arrangement according to claim 2 »dedireh gekennaeichn e t that all uncooled, high-time-resolving detectors (30) a photomultiplier is used. 109819 / 16S7 BAD ORlGlNAl. Blank page