EP0453519A1 - A chemical process yielding stimulated emission of visible radiation via fast near resonant energy transfer - Google Patents
A chemical process yielding stimulated emission of visible radiation via fast near resonant energy transferInfo
- Publication number
- EP0453519A1 EP0453519A1 EP90903260A EP90903260A EP0453519A1 EP 0453519 A1 EP0453519 A1 EP 0453519A1 EP 90903260 A EP90903260 A EP 90903260A EP 90903260 A EP90903260 A EP 90903260A EP 0453519 A1 EP0453519 A1 EP 0453519A1
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- Prior art keywords
- vapor
- source
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- reactant
- atoms
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/095—Processes or apparatus for excitation, e.g. pumping using chemical or thermal pumping
Definitions
- Classical laser operation in general requires a population inversion in which the upper energy level associated with the lasing transition is more populated than is the lower energy level on which the transition terminates.
- Laser oscillation can be established in an optical cavity which allows photons to be reflected back and forth and interact with each other so as to build up the intensity of the radiation.
- a select group of lasers including primarily N 2 which operates in a pulsed mode under amplified spontaneous emission, does not require such an optical cavity as the photon amplification is so large that sufficient intensity is produced without the necessity of mirrors.
- a further technique involves stimulated Raman pumping in which an intense laser beam is converted into a beam of another frequency by coherent Raman stimulation in a two or more step scattering
- Each of these lasers operates on electrical energy.
- infrared chemical lasers there are two main types.
- the first type involves the mixing of an oxidizer and a fuel gas to produce a continuous output.
- the mixture is activated by an electrical discharge or by thermal decomposition induced using arc heaters or combustors.
- the activated mixture produces a reaction initiating species, the reaction sequence eventually leading to a population inversion and lasing involving one of the constituents of the mixture.
- the second type uses premixed fuels and oxidizers which are activated by flash photolysis with an electron beam or a pulse discharge.
- Hydrogen halides and carbon monoxide are the two main types of molecules used as lasing species in these chemical lasers.
- Patent No. 4,553,243 This laser operates by expanding the reactant gas mixture continuously through a supersonic nozzle and applying a pulsed electrical discharge to initiate the chemical reaction resulting in the production of the lasing species.
- the frequency of the electrical pulses can be adjusted so as to regulate the frequency of the laser.
- the gas mixture is introduced on the fly, usually at pressures from a few Torrs to
- This laser does not operate as a purely chemically driven system as it requires an electrical discharge to initiate the chemical reaction. More importantly, this laser only operates in the infrared region and cannot produce visible lasing.
- a chemical oxygen-iodine laser using iodine chloride as a reactant gas is disclosed in U.S. Patent No. 4,563,062.
- iodine chloride is vaporized and entrained in argon gas. This gas mixture is directed into a laser cavity where it is mixed with singlet
- the atomic iodine is excited to a lasing state through collisions with the singlet oxygen.
- These lasers are typically operated with a laser cavity pressure in the range of 1-3 Torr.
- oxygen-iodine system one produces a laser which operates at 1.3 ⁇ , in the infrared region. Such systems have not been developed to produce visible lasers.
- a typical semiconductor laser, based on the gallium arsenide semiconductor, is disclosed in U.S.
- Patent No. 4,446,557 This type of laser requires that an external electric field to be applied using an electrode located on the semiconductor layers. When the external electric field is applied, photons are created which resonate among the semiconductor energy levels so as to produce lasing action.
- semiconductor system is at a much longer wavelength than the laser of the present invention and operates among much lower lying energy levels.
- Metals having sufficient vapor pressures at relatively low temperatures can be made to lase.
- metals have been heated in electric or gas fired furnaces to approximately 1675-1S75oK.
- the large amounts of metal vapor required to make such a laser practical require considerable electric power for heating, thus making the resultant laser very bulky and not readily susceptible to mobilization.
- the use of a gas fired furnace, which is more mobile than an electric furnace, lessens this problem to some degree but the system is still bulky.
- the use of either an external oven or discharge heating to produce the high temperatures of between 1675 and 1875°K makes it difficult to construct the fast discharge circuitry needed for excitation of other self-terminating neutral metal laser transitions.
- Using metal halides helps to reduce the temperature requirements to some degree. The
- the source of silcon or germanium atoms required to produce metastable storage states which make operative several of the systems of the present invention may be obtained from gaseous silane or germane oxidation reactions as noted in the following Detailed Description of the Invention.
- a number of the metal atoms required as energy recipients and subsequent atomic lasants can be obtained from sources operating at temperatures considerably less than 1600K.
- metal vapor lasers are not premised on chemical processes such as those reactions used in the present invention. First, there is no chemical reaction. Second, when based on the metal halides, they generally employ dissociation processes caused by an external laser. Third, they are largely operative in the infrared region with only a few examples operative at shorter wavelengths.
- Chemically driven visible lasers offer attractive alternatives to their infrared counterparts; however, the development of a chemically pumped system lasing in the visible region, while occupying the interest of
- the present invention is a visible chemical laser system based on an efficient near resonant (greater than or equal to gas kinetic) energy transfer involving metastable excited states of metal or semimetal monoxides, formed in the reaction of metal or semimetal atoms with ozone, N 2 O, or NO 2 , and Group IIIA 2 P 1/2 atoms in the lower spin orbit component of their ground electronic states (X gl ). This energy transfer populates the Group IIIA 2 S 1/2 excited state (X*) creating a population inversion which
- the present invention is the first known to create a population inversion in a final subsequently lasing constituent via a near resonant intermolecular energy transfer from another constituent formed in a select chemical reaction.
- the inversion is manifest in the stimulated emission of visual radiation.
- This single pass superfluorescent system is converted to a multipass laser oscillator (3% output coupling) with a corresponding increase in laser output power correlating with a
- Fig. 1 is an elevation, partly in section, of a typical reaction configuration associated with the present invention including an oven assembly utilized in forming
- Fig. 2 is an elevation, partly in section, of an alternate embodiment of an oven assembly associated with the present invention utilized in forming MO metastable molecules;
- Fig. 3 is a schematic view of the oven source used to produce a vapor of gallium, indium or thallium atoms in near-resonant energy transfer experiments;
- Fig. 4 is a top view of the oven configuration and photon path to the spectrometer in the near-resonant energy transfer system
- Fig. 5 are representative energy level diagrams for thallium, SiO a-X, and GeO a-X systems of the present invention
- Fig. 6 is the energy level diagram for three level laser systems, created using the fast intermolecular energy transfer concept of the present invention as a pump (R) to create an inversion and lasing (L);
- Fig. 7 are the energy levels and pump and lasing transitions for the tin and lead receptor systems of the present invention.
- Fig. 8 is the chemiluminescent emission from the
- Fig. 9 is a top view of the reaction zone configuration in the oscillation system.
- Fig. 10 is a top view of the oven configuration and photon path in the oscillation system.
- Fig. 11 is the energy level diagram for the energy transfer process for the Mo*-Ti system. DETAILED DESCRIPTION OF THE INVENTION
- the present invention employs the concept demonstrated by the superfluorescence associated with an atomic transition of a Group IIIA metal or semimetal atom.
- Group IIIA includes semimetals, such as boron, the term metal will be used throughout this
- the metal oxide (MO) excitation is transferred to a Group IIIA atom (X), specifically and preferably thallium, but also including gallium, leading to a pumping from the ground state X gl to energetically accessible electronically excited levels, X*, of the Group IIIA atom.
- the electronically excited thallium atoms, X*, pumped by energy transfer subsequently undergo transitions from X* to X gu .
- the potential laser transition X to X gu can be made superfluorescent.
- the superfluorescent transition corresponding to:
- the second step occurs in a fast, near-resonant, energy transfer from the metastable states of metal oxides or metal halides preferably SiO and GeO (although silicon and germanium generally are considered to be semimetals, the term metal will be used throughout this specification to denote both silicon and germanium as well as all of the elements, whether metals or semimetals, in Group IVA), to readily lasing atoms which include the Group IIIA metals, preferably thallium but also including gallium.
- This transfer is facilitated primarily by the near resonance of the metastable metal oxide energy levels and the energy required to pump the electronically excited state energy levels X*, for example, of the thallium and gallium atoms as illustrated in Fig. 5.
- the upper level spin orbit component X gu acts as the terminating level in a three level laser scheme.
- the metal to be oxidized to form metastable excited states is heated to a temperature producing a vapor pressure between approximately 10 -1 and 2 Torr.
- the operating temperature is preferably between about 1800. to 2000K; for germanium the temperature range is approximately 1600-1850K. These temperatures produce a sufficient concentration of metal vapor for the energy transfer-lasing process especially after
- the metal vapor 14 is entrained in an inert gas flow 18.
- This metal vapor/inert gas mixture 24 is introduced into the reaction zone 70.
- One method of accomplishing this is diagrammed in Figs. 1-4.
- the metal to be oxidized is held in a graphite crucible 10 which is heated by a tungsten basket resistive heater 12 insulated by extensive tantalum and zirconia baffling 16. Power to the heater 12 is supplied through electrodes 11.
- the crucible 10 is generally brought to temperature over a two-hour period.
- the metal vapor 14 effusing from the crucible 10 is entrained in an argon flow 18 being supplied through a circular directed slit configuration 15 below the lower portion of a concentric ring injector 17, and forming a combined metal vapor/inert carrier gas flow 19.
- the metal to be oxidized can also be oxidized in the oven assembly 108 of Fig. 2 which is an alternate, but equally appropriate, embodiment of the oven assembly 8 of Fig. 1.
- Oven assembly 108 incorporates parallel features to oven assembly 8, and is likewise numbered in parallel.
- crucible 10 in Fig. 1 is replaced with crucible 110 in Fig. 2
- electrode in Fig. 1 is replaced with electrode 111 in Fig. 2 , and so on.
- This oven assembly 108 operates in a similar manner to oven assembly 8, the major difference being the precise orientation of the entrainment configuration 117 including ring injector 121 which are modified to optimize the gas flow and entrainment in a given pumping configuration.
- the effective vapor pressure of the metal vapor in the argon flow will be a little higher than the vapor pressure mentioned above.
- the crucible used need only be a low porosity, non-reactive container in which a Group IVA (as previously noted, all of the elements in Group IVA, whether metal or semimetal, will be denoted in this specification as a metal) or other appropriate metal may be held during heating.
- a Group IVA as previously noted, all of the elements in Group IVA, whether metal or semimetal, will be denoted in this specification as a metal
- the temperature to which the metal which reacts to form the metastable energy storage state is heated and the volume of argon flow are adjusted to achieve the desired result.
- a subsequent lasant is typically placed in a second crucible 30 and heated to a temperature producing approximately a 10 -1 to 10 Torr vapor pressure.
- a temperature producing approximately a 10 -1 to 10 Torr vapor pressure.
- Group IIIA metal, thallium one generally wishes to operate the particular system described in Figs. 1-4 at a temperature close to HOOK. This operating temperature provides approximately a 1 Torr vapor pressure or higher, which is the preferred concentration of the atomic receptor metal vapor,
- An inert carrier gas 34 is passed through the top of the crucible 38, forming a flow of an atomic (ex:
- Group IIIA metals thallium and gallium metal vapor/inert gas mixture 40 which intersects the metal vapor/inert gas flow 24, in the reaction zone 70.
- the maximum vapor pressure of atomic receptor metal vapor is just below the concentration at which the oxidation reaction which forms the metastable metal oxide (ex: rxn of Group IVA metals Si or Ge) may become self-quenching.
- Any inert gas may be used as carrier gas 34, however, argon is preferred because of its molecular weight and lower cost. Further, any containers may be substituted for the crucibles so long as they are non-reactive with the metal to be
- thallium can be placed in an aluminum oxide crucible 30 which is heated to a
- a tantalum wire resistive heating configuration 32 operating at about 12 amperes at 10 volts alternating current.
- gallium or indium As the Group IIIA metal, higher temperatures are needed. This is now accomplished by supplying up to 70 amperes at 2.5 volts a/c to a tungsten wire basket heater 32 through electrodes 35. Further the alumina tubes 36 bringing inert carrier gas to the crucible are still heated using a tantalum wire configuration 37 of the design of Fig. 1 is used. This same modification can also be used for thallium.
- the crucible 30 generally was brought to temperature over a two-hour period.
- the argon gas 34 is passed through alumina connecting tubes 36 and through the top 38 of the crucible 30.
- the thallium vapor/argon mixture 40 forms a flow which is directed perpendicular to and intersects with the metal vapor/inert gas flow 24, described above in the reaction zone 70.
- the alumina tubes 36 and top of the crucible 38 are heated by tantalum wire resistive heating 37 to eliminate the possibility that a cooler argon entrainment flow 40 might result in severe condensation problems.
- the thallium atoms have a velocity in excess of 7 ⁇ 10 4 cm-sec -1 and travel across the reaction zone 70 in less than
- the two metal vapor flows may be brought to the reaction zone in parallel through a concentric injector comprised of one tube located inside a second tube. The size of the reaction zone depends upon a number of factors including the relative locations of the two metal source
- the system is capable of either lasing or fluorescing.
- the receptor metal vapor/inert gas flow 40 must first mix with the metal vapor/inert gas flow 2 4 in the reaction zone 70.
- an oxidant 20, which for metastable metal oxide formation is typically NO 2 , N 2 O, or O 3 dictated by the particular metal reaction and energy transfer partners is introduced into the reaction zone through the upper portion 21 of the
- the concentric ring injector system 17 For example, for the Ge-GeO-Tl system the oxidant of choice is O 3 ; for the Si-SiO-Pb system the oxidant of choice is N0 2 . The introduction of the oxidant 20 triggers the lasing
- Fig. 4 represents a top view of the oven configurations and optical system for measuring a
- superfluorescent laser pulse includes two light baffles (54, 56) to shield the detectors from oven system blackbody radiation, two high quality quartz windows (52, 58) and a focusing lens 59.
- two light baffles 54, 56
- high quality quartz windows 52, 58
- a focusing lens 59 59
- reflective mirror 50 has been employed. This represents the first stage in the creation of a full oscillator multipass configuration.
- one method of controlling the O 3 flow to the reaction zone 70 is to freeze the O 3 down on a silica gel trap at dry ice temperature, then passing a flow of O 3 through a short stainless steel tube to the concentric ring injector 17 using a triggered pulsed valve or a manual needle valve (not shown). If the O 3
- the O 3 flow can be backed with an inert carrier gas, such as helium, in order to increase the O 3 vapor pressure in the reaction zo ⁇ e 70.
- an inert carrier gas such as helium
- the vapor pressure of oxidant in the reaction zone will be less than 1 Torr and preferably in the range of about 5 ⁇ 10 -2 to 2 ⁇ 10 -1 Torr.
- the oxidant flow may be either continuous or pulsed. However, once the reaction - energy transfer sequence leading to
- the key to effecting stimulated emission of visible radiation using the present invention is the formation of a sufficient concentration of metastable or triplet excited state metal oxides or, as described below, metal halides by chemical reaction. These metastable states must be sufficiently long-lived to first store energy from the chemical reaction and then must be capable of transferring that energy on a sufficiently fast time scale to a medium capable of emitting at least a portion of this energy as visible radiation.
- metal oxidations lead to formation of metastable storage states of the Group IVA metal oxides, such as GeO and SiO.
- the ratio of the Group IIIA metal, such as thallium, to the Group IVA metal oxide, such as GeO*, is preferably between 1:1 and 1.5:1.
- the mixing sequence is important in these systems. To induce lasing action, the metal vapor which is oxidized to initiate the superfluorescent sequence must first be mixed with the receptor atom which will produce the stimulated emission event. The oxidant then triggers the lasing sequence as it is introduced into the reaction zone in a pulsed or continuous fashion. If this sequence is not followed, it is more likely that the system will fluoresce and not lase. In order for the system to display energy transfer primarily in the form of receptor atom fluorescence as opposed to lasing, the metal
- vapor-argon flow 24 is mixed with various oxidants 20 as it is introduced into the reaction zone 70.
- the oxidant 20 mixes with the metal vapor/inert gas flow 24 via a
- vapor/inert gas flow 24 mixes with the oxidant as it enters the reaction zone 70, a metal oxide flame 24 is produced. More specifically, an entrained Group IVA metal flux 14 under multiple collision conditions reacts with the oxidant 20 to produce MO*. If at this time the Group IIIA metal vapor/inert gas flow 40 is introduced into the metal oxide flame, the probability for observing a
- an entrained Si flux under multiple collision conditions reacts with an oxidant, specifically NO 2 , N 2 O, or O 3 , to produce SiO metastables or an entrained Ge flux under multiple collision conditions reacts with an oxidant, specifically NO 2 , N 2 O, or O 3 , to produce SiO metastables or an entrained Ge flux under multiple collision conditions reacts with an oxidant, specifically NO 2 , N 2 O, or O 3 , to produce SiO metastables or an entrained Ge flux under multiple collision conditions reacts with an oxidant, specifically NO 2 , N 2 O, or O 3 , to produce SiO metastables or an entrained Ge flux under multiple collision conditions reacts with an oxidant, specifically NO 2 , N 2 O, or O 3 , to produce SiO metastables or an entrained Ge flux under multiple collision conditions reacts with an oxidant, specifically NO 2 , N 2 O, or O 3 , to produce SiO metastables or an entrained Ge flux under multiple
- metastables For most efficient usage, these metastables must usually be formed after the two metal flows employed are mixed previously in order to insure lasing action.
- the thallium system is characterized by emission features resulting at least in part from the chemical pumping of efficiently produced X gu atoms formed via the initial pump - superfluorescence, fluorescence sequence described above followed by:
- the Tl gu atoms are created in the reaction-energy transfer zone, as is indicated by the thallium emission at 3525A resulting from the transition from Tl # * to Tl gu .
- the Tl#* energy levels can be populated through pumping of Tl qu in a near resonant energy transfer from MO*, the energy increment also being close to that for pumping from Tl gl to Tl*.
- the intensity, pressure, and reactant concentration dependence of the emission at 3525A are consistent at least in part with the presence of a Tl gu concentration in the reaction zone, which subsequently is pumped to the Tl#* manifold through the reaction:
- gallium may also be used as a lasing species chemically pumped through energy transfer from a Group IVA metal oxide, such as SiO and GeO.
- a Group IVA metal oxide such as SiO and GeO.
- cold, nonreactive CO, CO 2 , or N 2 can be used as an entrainment gas so as to relax these X gu , atoms before energy is transferred to them from the excited metal oxides.
- a direct extension of the thallium and gallium laser systems corresponds to the Si-SiO-Pb system where the oxidant reacting with Si to produce the SiO metastables is NO 2
- the fast near resonant intermolecular energy transfer concept which we have outlined, has focused on a pump of thallium and gallium excited states, X*, but can be readily extended if we consider that all of these systems should operate on the basis of energy storage created by a reaction whose exothermicity exceeds 2.5 eV (or approximately 58 Kcal/mole).
- the near resonant energy transfer concept can be used as an efficient pump for somewhat longer lived emitters (allowing a further
- ⁇ S spin angular momentum selection rule
- the energy transfer pump will be inherently considerably more efficient.
- metastables at least two orders of magnitude in excess of those already obtained, is by no means a slight variant on electric discharge techiniques. In fact, it represents a discharge enhanced primarily chemical process. This approach allows one to bring the SiH radicals (GeH), silicon atoms (Ge) and receptor atoms into intimate contact for the purpose of premixing before the
- the data in Fig. 8 indicates the range of wavelengths over which the selectively formed excited electronic state emits.
- the ScF selective emission feature peaks at 3500 ⁇ whereas the corresponding YBr feature peaks at 4040 ⁇ .
- the concentrations in the reaction zone are Ge ⁇ 2 ⁇ 10 14 atom/cm 3 , O 3 ⁇
- the upper 2 P 3/2 component of the ground state thallium atom can act as the terminal level in a three level laser provided that this state is not populated before the lasing pump-sequence is initiated.
- the single pass superfluorescent thallium laser amplifier system described above can be converted to a multipass laser oscillator with a corresponding increase in laser output power correlating with a substantial increase in the ratio of superfluorescence to fluorescence and the display of a significant directionality.
- the optical cavity consists of two concave mirrors 103, 104, one totally reflective mirror
- the cavity dimensions are by no means rigid and the mirror configurations and output coupling can be modified to obtain optimization.
- the mirror separations, radii of curvature, location of the gain medium relative to the cavity mirrors, and the degree (percent) of output coupling can be modified to optimize several possible systems.
- the cavity length is about 30cm with the reaction (amplifying medium) zone 105 being about 1-1.5cm long, and thus the two mirrors 103, 104 are in a stable resonator configuration.
- the reaction zone and cavity dimensions are operational but by no means optimal and can be
- a HeNe laser 106 which is used to align the cavity also specifies the region of the much shorter amplification zone 105 which will be sampled.
- the "lever arm" formed by the HeNe laser beam about the amplification zone 105 as it passes through this region central to the current 30 cm cavity 101 has a significant moment as the present system by no means constitutes an optimal cavity configuration.
- This laser system has also been probed temporally using a 125 MHz digital oscilloscope in conjunction with two monitoring configurations.
- the laser cavity 101 was aligned with the incident slit of a monochromator 107 set at 535. lnm, operating at lnm
- the production of Si, Ge, SiH, and GeH through reactive discharge and reactive stripping of the volatile silanes and germanes creates the precursors which are subsequently oxidized to form the metastable states of SiO and GeO. It is also feasible to use highly volatile precursor compounds as sources of the metal atoms to which the energy stored in the metastable metal oxide states is transferred in a fast near-resonant energy transfer collision to form an atomic amplifier. As an example, the thallium and gallium systems could readily employ volatile multiply ligated hydrides or methyl
- transition series (Group IIIB - VIII), form the multiply ligated and volatile metal carbonyls as well as the metal hydrides.
- the efficiency of the MO*-Tl amplifier oscillator system can be improved by introducing a quench gas such as atomic iodine or water vapor into the reaction zone to efficiently deplete the Tl 2 P 3/2 level through
- a CO 2 laser can be employed to enhance the superfluorescent Tl atom stimulated emission process described above. Distinctly different energetics must be considered when assessing oxidation in those systems which form the basis for the MO*-Tl and MO*-Ga transfer laser amplifier systems.
- the gallium atoms are cooled
- the P 3/2 level population is still substantial.
- the initial population of the Ga 2 P 3/2 level places a considerably higher pumping efficiency requirement on the MO*-Ga energy transfer process which populates the 2 S 1/2 level to create a population invention relative to the P 3/2 level as represented in Fig. 9 for the Tl system.
- Amplification on the 2 S 1/2 - 2 P 3/2 and 2 S 1/2 - 2 P 1/2 gallium transitions is strongly influenced by the reactive removal of X 2 P 3/2 and X 2 P 1/2 gallium atoms from the energy transfer zone.
- the Tl 2 P 3/2 (7793 cm -1 ) - O 3 reaction is about 500 cm -1 endothermic excluding reaction barriers.
- any marginal bonding in TIO will decrease this endothermicity, suggesting that the Tl
- ( 2 P 3/2 ) - O 3 reaction may well be thermoneutral or
- the enhancement of the depletion of the Tl 2 P 3/2 metastables depends on the efficiency of the combined pumping of Tl X 2 P 1/2 to 2 S 1/2 and the subsequent emission rate from 2 S 1/2 to X 2 P 3/2 versus the efficiency of the CO 2 laser induced reactive depletion for the 2 P 3/2 level.
- the reaction rates associated with the gallium system indicate the high probability for enhancement of the Tl 2 P 3/2 level reaction (depletion) rate.
- the CO 2 laser enhancement scheme as applied to Tl 2P 3/2 is of general applicability. Given that a CO 2 laser enhancement significantly increases the reaction rate of a terminal metastable bottleneck level in the amplifier schemes discussed above, the effect of this enhancement increases with a decreasing transition moment (slower radiative population rate from upper laser level) for that transition which shows amplification as it feeds the terminal bottleneck level.
- the general three level schemes considered previously provide a multitude of possibilities both from the standpoint of terminal
- the CO 2 laser enhancement scheme is applied in a general fashion to the three level laser sequence as a means of increasing the reaction exoergicity and rate of an oxidant-metal atom reaction involving the terminal laser level.
- This enhancement requires the excitation of the infrared vibrational modes of the oxidant using a medium powered CO 2 laser. If we require operation with more tightly bound oxidants (i.e. NO 2 versus N 2 O or O 3 ), the CO 2 laser enhancement process is also applicable; however, those oxidants must interact with a higher CO 2 laser fluence in order to gain higher vibrational excitation in order to possess sufficient internal energy to facilitate an exothermic reaction with the terminal laser level. It now becomes apparent that the above described chemical processes yielding stimulated emission of visible radiation via fast near resonant energy transfer and the apparatus for carrying said process are capable of obtaining the above-stated objects and advantages. It is obvious that those skilled in the art may make
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Abstract
Le procédé décrit, qui sert à produire un émission stimulée de rayonnement visible via le transfert rapide d'énergie intermoléculaire quasi résonnante, consiste à faire réagir une première vapeur métallique ou semi-métallique avec un réactif pour obtenir un produit de réaction à l'état excité métastable, puis à transférer l'énergie stockée dans l'état excité métastable du produit de réaction vers une seconde vapeur métallique ou semi-métallique, en utilisant le transfert d'énergie quasi-résonnante, afin de former des atomes récepteurs électroniquement excités selon une inversion de population par rapport à un niveau inférieur d'excitation des atomes récepteurs. Dans le mode de réalisation préféré dudit procédé, la première vapeur métallique ou semi-métallique est constituée par un élément de groupe IVA ou IIIB. La seconde vapeur métallique ou semi-métallique est choisie parmi les éléments de groupe IA, IIA ou IIIA suivants: scandium, yttrium, vanadium, fer, nickel, titane, chrome et étain, et le réactif est soit de l'ozone soit de l'oxyde d'azote soit du dioxyde d'azote soit un halogénure. Grâce à l'utilisation de ce procédé, on peut produire un oscillateur laser (101), en permettant par réflexion multiple au moyen de miroirs (103, 104) le passage répété de lumière à travers le milieu à gain inversé dans une zone de réaction (105).The method described, which is used to produce an stimulated emission of visible radiation via the rapid transfer of quasi resonant intermolecular energy, consists in reacting a first metallic or semi-metallic vapor with a reagent to obtain a reaction product in the state metastable excited, then transfer the energy stored in the metastable excited state from the reaction product to a second metallic or semi-metallic vapor, using quasi-resonant energy transfer, in order to form electronically excited receiving atoms according to a population inversion with respect to a lower level of excitation of the receiving atoms. In the preferred embodiment of said method, the first metallic or semi-metallic vapor consists of an element of group IVA or IIIB. The second metallic or semi-metallic vapor is chosen from the following group IA, IIA or IIIA elements: scandium, yttrium, vanadium, iron, nickel, titanium, chromium and tin, and the reagent is either ozone or l Nitrogen oxide is either nitrogen dioxide or a halide. Thanks to the use of this method, a laser oscillator (101) can be produced, by allowing multiple reflection by means of mirrors (103, 104) the repeated passage of light through the inverse gain medium in a reaction zone. (105).
Description
Claims
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
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US296512 | 1989-01-12 | ||
US07/296,512 US4951297A (en) | 1989-01-12 | 1989-01-12 | Chemical process yielding stimulated emission of visible radiation via fast near resonant energy transfer |
US07/375,049 US5050182A (en) | 1989-01-12 | 1989-07-03 | Chemical process yielding stimulated emission of visible radiation via fast near resonant energy transfer |
US375043 | 1989-07-03 | ||
US375049 | 1989-07-03 | ||
US07/375,043 US5020071A (en) | 1989-01-12 | 1989-07-03 | Chemical process yielding stimulating emission of visible radiation via fast near resonant energy transfer |
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EP0453519A1 true EP0453519A1 (en) | 1991-10-30 |
EP0453519A4 EP0453519A4 (en) | 1992-09-23 |
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EP19900903260 Withdrawn EP0453519A4 (en) | 1989-01-12 | 1990-01-10 | A chemical process yielding stimulated emission of visible radiation via fast near resonant energy transfer |
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JP (1) | JPH04502686A (en) |
AU (1) | AU5081490A (en) |
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US7435391B2 (en) | 2003-05-23 | 2008-10-14 | Lucent Technologies Inc. | Light-mediated micro-chemical reactors |
US7391936B2 (en) | 2005-01-21 | 2008-06-24 | Lucent Technologies, Inc. | Microfluidic sensors and methods for making the same |
US7780813B2 (en) | 2005-06-09 | 2010-08-24 | Alcatel-Lucent Usa Inc. | Electric field mediated chemical reactors |
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---|---|---|---|---|
US4334200A (en) * | 1980-05-01 | 1982-06-08 | Bell Telephone Laboratories, Incorporated | Laser induced collisional laser pumping |
US4381565A (en) * | 1980-11-25 | 1983-04-26 | Westinghouse Electric Corp. | Radiative removal of lower laser level bottlenecking |
US4380072A (en) * | 1980-12-22 | 1983-04-12 | Stanford University | XUV Laser and method |
US4759179A (en) * | 1987-07-20 | 1988-07-26 | Rockwell International Corporation | Method for generating electronically excited NF for use in a laser |
-
1990
- 1990-01-10 EP EP19900903260 patent/EP0453519A4/en not_active Withdrawn
- 1990-01-10 AU AU50814/90A patent/AU5081490A/en not_active Abandoned
- 1990-01-10 JP JP50339890A patent/JPH04502686A/en active Pending
- 1990-01-10 WO PCT/US1990/000255 patent/WO1990008414A1/en not_active Application Discontinuation
Non-Patent Citations (2)
Title |
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No further relevant documents disclosed * |
See also references of WO9008414A1 * |
Also Published As
Publication number | Publication date |
---|---|
EP0453519A4 (en) | 1992-09-23 |
WO1990008414A1 (en) | 1990-07-26 |
JPH04502686A (en) | 1992-05-14 |
AU5081490A (en) | 1990-08-13 |
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