DE1926679A1 - Ion laser - Google Patents

Description

iiULuig refer .. 'cicu to Io: ie ..- La. or, p ^ zidl

ionJ -i-Lu -ι, aie un ¹ er Vetw.-r.jung von Quarzgjfäßü uufgebau .-- irju.

ß ^ i jüuem La. e * r eazäug. * - Ji .. relik "iv-r Ar'.regungsmecua-.ii: IU; ■ - ei.iwn abr.orm: .O; .en Αηε-il for energe i-fciie Zu-. * ä.; ue i:; uei; ialb a «- L- ^ imuliurbarem r. ^ aium .:, wodurcn öii. as I-; ver. ior. j-jr Be ..- a ^ zung." stranding known For-: anu generates- wira. When the in d ~ nr ^ öner energe'-iscner. Ingredients located there areixeu particles in add-t-ä; .ae lower energy overgü.ien, t; ~ ra: Ju :: g in aericn ⁺ igen Puül-ö in small Preq_uenzbereicii stimulate * ·, which around egg. .e oüarak ^ eristiEcne frequency cen- ^ rier ^ is. The stimulated transmission of this signal at the oiiarakteric ^ iaciieu frequency is used in lasers for light amplification or for the production of conventional light.

Wherein as the, Ionan laser bekanrite special GAES-lat-er, a comparatively high -electric S ^ rom durcn a gas plasma liindurchgeechick ⁴ -, which ionizes the gas, and a bet RACH ⁴ -liehen fraction of ions au a reversal of the population distribution stimulates. Argon is the gas most commonly used in ion lasers, and in order to obtain a reasonable reversal of the population distribution in the ionan eu, the argon pressure must be relatively low in comparison with other major charges.

909851/1555. '

6AD OWGtNAL

ri cn ⁴ -Uu ge η ze ± u. The Ga.druck 1ε- -ypi ^ c-aerwei ^ e. less than a lorr.

jSi:; te aaup. begrsi-.zuiig at Ione bearings ..- i: iie In Gu benrlaaungsbereica erzeug ^u e heat. To define aie liittelöffnu.jgeein ar Reine vo; - Me ^v all ^ o:. = Ibe: i, aie-r aucn aie die jltii-laaui can be used to define the linear gases .g beglel-.erue dissipate heat: .. ü; i wurae auc: · arkann ", aa3 because of .asr generate heat aas α -. = ..-, λγ-gongas inner vessel preferred? weire au-. quartz r.erges'ell ^ will, the uocrini ^ zebe-ctendet i ^ ", a ;, never i- ■ -" - rigen ^J -.iermi £ ..cric-n Äu.de: inurig:. 'k: oeffizie .i ^ er. besi-'zt- and ⁷ no impurities ir. di ^ ün * charge introduced for * ·. * · Finally, because argon riicn * he use it, diffuse into quartz +, the latter generally ali. good vessel material for the absorption of argon ?: beracn.'e-. - '

The linear gas discharge line can using an axially oriented - *: en magnetic field along the En + - laäungssTrecfee are constricted. Hierdurcii increased : ieii the density of the particles in the gas discharge Ulla with it aie gain and output power.

While ion lasers that have the improvements mentioned above show significant advantages, such as high output power and the ability to generate certain optical frequencies, which is why they are widely used for welding, surgical purposes and other uses

BATH ORIGINAL

1926B ¹ FS

w / eie.e zu op ir.Gi.a., '.'άο.αίόιΓ eimbei'vraguiigiizwekkc.i Unu αεί same v ^ rv »5iije ⁴ weraenj nabe .; ^ it cine shorter Iieb-yäi.aaiier old; some of the developed Fe.5'-body La ^ ei.

Accordingly, "ie ^a e; task of the üri'inäungi uie Liebeltr-atcüer of the Ioiien-Laser to eriiön"

The Ui on which the determination is based _; *: er _: uöiiUMg the iöiien-Lai-er showed that the liaup 'säculidhe Lebei:> - external £; chrä: ikung hurry to reduce dee Ärgongu-printed i. ■ ^ die durcli Zerp ^: äube: j aer Me-all ^ chiben verUrieir will » I) a.-j Zert-'äube .; can in further. '. iiciie-n dauuic.i eliiüir.iervi / erde; i that the distance züvicche :: aufei: a.: derfblge; iaen Metallirclieiben weseii-licii greater g-sm & bh ¹ - V »ird than the diameter aer Mi ^ + eiGffnuijg, Wöäurcia the eiek'-risciieri fields between the Scieibiii, the kaup ". äciilich. caused for the atomization. Λ:. ^, be reduced:» since :; Mag :: e fela lä-.g ^ aer u .. 'lc.aurigceirecke erlaub- AEIE ^ e modification frosting because of jiiiitGixJÜrung aer i :. · lauung j wöüurcii one of jjJn ^one charge zMsciien the öcaeiben reauzier ⁴ - wild. Jeaoeii resulted in dix, QaB telbs · ¹ - nacii jjraktiscii complete elimination of the Me ^ älÄrs + exercise which during the., rgön laser still, begience

The investigation: iiaben also geiseig +} that zvrar itrgbi] nicir- dürcii the Qia "z vessel of the -iiasere fiiiiäurefi-

can diffuse ^ but on the inner surface; _

8 0BeViVi 6 68- ' ^V ■ BAD ORIGINAL

Vessels ;; aa. ar bier · will. Although ^ rgonu ome ei cn im - ^; Course of the Z ~ i '"on the inside: upper flask of the vessel: ■ '" ■ - - ^; - "ii. a higher ⁴ enr. aonoatomaren schicL · + precipitate, reduce ¹ - this precipitate or, the ye adsorption: the pressure within the. discharge area Laa failure. ⁴ In the unterüaeh- 's Rohre.'i Uimin-i- the iirgouadsorp-'ion with a Zei ^f constant of about 75 hours from exponentially, which leads to a typical reasons Latjer-Lebencda.uer of 50 S. . ■ -; -

It has now been found that such an Ad can be reduced or eliminated if that part of the quartz vessel which runs along the linear gas discharge path is covered with a thin Alia.-; miniumoxide-1-layer (Al ₀ O,) coated. Since, as yet '' explains the vessel only argon ions, but not ^ A ^H ome adsorbed, it is not necessary, those - which is Γ-eildes coating vessel not exposed to the discharge _ - ¹ * ". ':

With a vessel coated in this way according to the invention , one obtains, as has been found, a typical ten-fold increase in the life of the ion laser.

In the following the invention is based on the drawing be ~ veryieb, who made a longitudinal section through a Jonen « Laser in schematic,! Representation shows.

^: - ■ - '* ■ "■■■""" BAD ORIGINAL

909851/1555 y

In the drawing 'is a direct current excited Ion laser shown holding a tubular vessel 11, a cathode 12 and an anode 13. That Vessel is filled with argon, which is known for the generation of a population inversion of the ion components is suitable if a gas discharge is maintained therein .will. As is also known, the argon gas pressure must normally be maintained below 1 torr and is usually between 0.05 and 0.2 Torr.

A linear gas discharge beam is through the central openings 16 of a series of disks 1? defined, each made of a metal with high thermal conductivity and a very high melting point, such as molybdenum. Each metal disk 17 is attached to an annular baffle 18 which, together with openings 19 in the disks 17, form a gas return path for gas pressure equalization within the vessel. As is well known, optimal operation of the ion laser requires a gas transport path parallel to the linear one. Is not charge s st recke, a _DER: slightly higher mechanical gas passage ^ Property Assets .besitzt, but extends than the linear discharge path over a greater length · The Baffein 18 extend the Gasrüokflußweg in that it Bwingejcti the gas from the openings 19 übNär eiöeö Sohmal bingspalt 20 and from there -from the largest opening 19 to flow. Through this the ßasrückflussös verhlnder "yuiirung the Baffein 18 a gas discharge durcfc ate Öff-

BATH ORIGINAL

openings 19 through, so limit the gas discharge on the central axis 15. The axial gas discharge is by a solenoid 22 from those discussed above Reasons constricted.

During operation, a relatively high current is generated by a current generator 23 which runs along the gas discharge path flows from the cathode 12 to the anode 13. This high current, for example in the order of magnitude of up to 15 amperes, causes a substantial amount Part of the argon atoms inside the vessel is ionized. In addition, the ions are excited into a state of reversed population distribution in which a abnormally high proportion of ions are excited to a higher energetic unstable state. If those Ions fall back into the lower, more stable energy states, they radiate I & cht laei a characteristic frequency according to the "well-known laser phenomena away.

The end faces of the tubular vessel 11 are through translucent windows 25 and 26 closed, the maximum increase in the transmission efficiency are inclined at Brewster's angle. l will the Device used as amplifier »this is how MeJit is one of the windows is inserted, then runs along the central axis 15 through, the anode and cathode through, the en this »purpose both designed as hollow cylinders are, and will «iUirendi of its passage because of the

additional effect iet stimulated radiation of the 98385 "" /

c ■. ■■ -. * "- ₇ 1 ^ 26679

stimulated ßasions amplify ¹ -. On the central axis 1p köujsn mirror either outside the device or έ ^Λ · at ⁴ the Pent! he will be attracted to the

■ ■ - '} ■ -

-reinforcement to multiply or by a sufficient one To feed back the radiation energy in order to do so to enable the device to perform ale; Oscillator or alu Laser light source to act.

For ion lasers of the now known and used Ar-- it is necessary that the argon pressure is not higher than a Torr lie; .-, so 'a sufficient proportion of the atomic components ionized and to the required Energy level is stimulated. On the other hand, the device becomes incoherent Lieh - * - by way of a stimulated Radiate emission when the argon pressure drops too far,

As mentioned above, the investigations on which the invention is based on the service life of the ion laser showed that a main cause of the failure of the device is the argon battery, which results from a considerable atomization of the metal of the disks 17, be ^ of the device shown i, this effect is largely characterized st _f eliminated eüa§ a significant distance, typically one to two centimeters, "wipe the Metallseheiben is adhered to, whereby the large electric fields d, comparable & teen £ e uiaeyiBafiges Zerstä? urs! ttGrhen _? are largely eltLmijaiert »In fact, the decency between aiifinaj3d§r # olgejQde, n §§he.ibeji 17

the Ze.fitral ». ,

BAD ORIGINAU

openings 16. This large distance is possible because the magnetic field constricts the discharge and therefore the Stigtfeffffekt reduced and the generation of a ■ well-defined Stromweges supported. Driving this aid increases the life of the ion laser considerably has nonetheless found that ion lasers after a typical operating time of about 50 Hours tend to fail due to an unacceptably high decrease in argon gas pressure.

Theoretical considerations suggest that this gas pressure drop or "gas cleaning effect ¹¹ results from the adsorption of ionized argon atoms on the inner surface of the vessel 11. The term" adsorption "denotes the trapping of particles on a surface without them penetrating the surface significantly If non-ionized argon atoms do not deposit on the surface of the vessel, ionized atoms inherently have sufficient energy to break the atomic bond between the individual atoms of the quartz on the surface to an extent sufficient for the argon ions to bind to the surface The idea was supported by calculations which showed that the number of missing argon atoms, corresponding to the observed drop in argon pressure, was approximately equal to the number of atoms extending along that surface area

of the vessel, which of the discharge 909851/1555

BATH ORIGINAL

exposed let.

If, therefore, the inner surface of the vessel, as far as it is along the linear i) ntladu; ₄ gsst stretch, would be coated with a material that is incapable of adsorbing argon ions, the harmful argon pressure reduction could be avoided and the service life of the device extended over the long term. ^1st will.

Furthermore, the coating material should not introduce any impurities under almost high vacuum conditions and at high temperatures and should adhere well to quartz. In order to prevent adsorption, it was considered that the atomic bond should be considerably stronger than with quartz (SiO ₂ ), so that the high-speed argon ions are practically incapable of breaking the atomic bond on the surface or to penetrate.

As has been found, the ce requirements are met by aluminum oxide (AlpO-z), which is used according to the invention to produce a thin coating 28 on the inner surface of the quartz tube 11. Because alumina has a higher ⁺ hermic coefficient of expansion than quartz, a thin layer of alumina is preferred, typically on the order of 2000 S. Although an extremely thin, uniformly deposited layer of the order of only one hundred Å will likely be sufficient, it is

more convenient to put down a 2000 S. d.ioke layer, 9 0 9 8 5 1/15 5 5

BAD ORiGINAL

and for this thickness it has been shown ¹ -. that tie a io large it- ⁴ : in order to lead to flaking and similar problems as a result of ⁺ hermit-rather interpretation. A vessel *: rush out. Solid aluminum oxide forbids it, partly because of its costs and the difficulties in the construction: - shaping and manufacturing.

The vessel 11 preferably has a hollow cylindrical quartz part 29, which is the same extent as the Ga ^ en ^ charge range, as well as the end parts 30, on which the i'ei.s'-er 25 and 26 mount ⁴ - dnd . Before attaching the end ^u eil3 30 apply the thin coating. 28 preferably generated by pyrolytic precipitation. For example, the quartz tube 29 is heated to 1000 to 1100 ° G and hydrogen made with aluminum chloride vapor is passed through the quartz cylinder together with a mixture of nitrogen and carbon dioxide. The aluminum chloride reacts with the carbon dioxide and hydrogen to form the aluminum oxide coating to a thickness of 2000 pounds in the course of about half an hour. Thereafter, the other components of the laser including the ends 30 are assembled. The coating 28 need only have the same extent as the BLz charge area, since this is the only zone in which argon ions are generated.

Tests have confirmed that the coating 28 does not adsorb argon ions, and pipes of the in The species shown in the drawing was found to be - ~

9 0 9 8 5 1/15 5 5 ^BAD original

1928679

they mi ^L of the oxide coating have a Lebenrdauer that ten times larger io ', as the life largely identical. but unb ec chi cht et he devices.

909851/1555 BAD OMOINAL

Claims (2)

- 12 - Claims ft: Ion laser with a vessel (11), can main part (29) consists of quartz and is intended to hold a quantity of argon gas. to generate an occupation reversal in the ionized state is measured »and with means (12, 13» 23) for generating a gas discharge in the gas to ionize the same to a considerable extent and generate it an occupation reversal for the ionic components » thereby stimulated emission of coherent optical radiation from at least one part to initiate the gas ions » characterized by a diine layer (28) Aluminum oxide on that part of the inner surface of the quartz vessel (29) which is along the gas discharge path (12 ^ 13) runs. 2. Laser according to claim 1, characterized in that • the aluminum oxide coating (28) has a bead Of the order of 2000 Å. \ 3 · Laser according to claim 1 or 2, characterized in that »! that the aluminum oxide coating (28) is formed J by a pyrolytic precipitate with the help of the reaction of alfiminium chloride with carbon dioxide and Hydrogen. BATH ORIGINAL 909851/1555