RU2311710C1 - Active material for liquid laser - Google Patents

Abstract

FIELD: producing liquid-phase active materials for optical lasers and pulsed or continuous-wave optical quantum amplifiers.

SUBSTANCE: proposed active material for liquid lasers has neodymium ion, tin tetrachloride, phosphor oxychloride, and triflat-ion, proportion of ingredients being as follows, mass, percent: neodymium ion, 1.5-7.0; tin tetrachloride, 2.7-12.5; triflat-ion, 2.3-16.0; phosphor oxychloride, the rest, relative content of neodymium ion and triflat ion being 1: 1.5-2.2.

EFFECT: preventing polymerization process at high concentration of rare-earth elements in solution.

1 cl, 1 dwg

Description

The invention relates to the field of creating liquid-phase active materials suitable for use in optical quantum generators (OCG) and in optical quantum amplifiers (OCU) with pulsed and continuous generation.

Organic dyes and solutions of rare-earth element chelates (REE) can be used as liquid-phase active materials for JAG and GAC. However, these materials are ineffective and have limitations due to the fact that they are not stable enough and do not withstand large energy capacities.

The most effective materials are REE solutions based on mixed aprotic inorganic solvents. Substances formed by such matrix solvents with rare-earth elements introduced into them have high spectral-luminescent and lasing characteristics and are suitable for use as active laser materials, including in liquid lasers with high radiation power.

Active materials for lasers with optical [RU No. 1568847], as well as with nuclear pumping [RU No. 2075143; Dyachenko I.I. and others. Preprint No. 2193, IPPE - Obninsk, 1991], which contain molecular mixtures of phosphorus oxychloride and anhydrous transition metal chlorides as matrix solvents.

The quantitative composition is most widely stated in the active material activated by rare-earth elements for optical quantum generators and optical quantum amplifiers [a.s. USSR No. 330505, Н01S 3/14, bull. No. 8, 1972], containing, wt.%:

phosphorus oxychloride 15-98 metal halide 1-60 rare earth element 0.1-25

The active materials of the above analogues have high spectral-luminescent characteristics, however, their common drawback is that the region of the liquid phase in them exists only when the concentration of the rare-earth element is in the range of 0.1-2.5 wt.%. At higher concentrations, the system goes into a resinous, glassy or crystalline state.

According to the requirements of manufacturability, the optimal system is a mixture of phosphorus oxychloride and tin tetrachloride activated by a neodymium ion [Aslanov LA, Gilyarov ON, Kulikovsky BN and other J. Coord.chemistry, 1982, v. 8, No. 6, pp. 723-736] (prototype). The choice of neodymium as a luminescent ion in the Nd ³⁺ - OPCI ₃ - SnCI _{4 system} is due to the industrial applicability of lasers with a generation at a wavelength of 1.06 Mk. The molecular mixture of phosphorus oxychloride and tin tetrachloride as a matrix solvent provides the neodymium ion with optimal spectral and luminescent properties.

The study of the material on the prototype revealed the following disadvantages:

- in solutions with REE concentration above 1.5 wt.%, a noticeable increase in viscosity is observed due to the onset of polymerization of the resulting neodymium compounds;

- solutions with a REE concentration above 2.5 wt.% lose fluidity, thicken, their viscosity rises to 2.5 cSt and the use of such materials in circulation lasers with pulsed and continuous generation is difficult;

- in systems with a rare earth ion concentration exceeding 3 wt.%, an increase in the concentration quenching of luminescence is detected, associated with a change in the nature of polymerization and the formation of multicenter polymers. [Aslanov L.A., Gilyarov O.N. et al. J. Coord. Chemistry, 1987, vol. 13, No. 6, pp. 758-760].

The listed disadvantages of the prototype are predetermined by the chemical nature of the starting components: in the manufacture of the active material, neodymium ion is usually introduced into the matrix solvent in the form of hydroxo compounds, since its anhydrous compounds do not dissolve. Under the influence of OH ^- groups, as well as H ₂ O molecules present in such compounds, the initial matrix solvent is easily hydrolyzed, which creates the conditions under which a neodymium ion, depending on its concentration, can form both mononuclear complexes and to be involved in multicenter polymers of complex composition and structure. It has been established that the viscosity in these systems increases with increasing concentration of Nd ³⁺ due to metal complex polymerization. So, in those cases when the concentration of Nd ³⁺ is 0.1-1.5 wt.%, Mononuclear complexes are formed in the system and the viscosity of such solutions is close to the viscosity of water. When 1.5% or more percent of Nd ³⁺ is introduced into the system, mononuclear complexes are aggregated to a resinous and glassy state, the viscosity of the solution increases and at a concentration of Nd ^{3+ of} 2.5 wt% exceeds 2.5 cSt.

Solutions with a viscosity of more than 2.5 cSt in practice cannot be used in circulation lasers, since when they are pumped, the optical uniformity of the active element is not ensured. Another significant drawback of such solutions is that neodymium ions involved in multicenter structures have shortened bonds among themselves, and this causes concentration quenching of the luminescence of the material.

The technical task is to prevent polymerization processes at a high concentration of REE in solution.

The invention is directed to obtaining an active material for a liquid laser, including circulation, with pulsed and continuous generation with the following characteristics at neodymium ion concentrations from 1.5 to 7 wt.%: Viscosity no more than 2.5 cSt; the coefficient of inactive absorption at a wavelength of 1.06 microns in the range of 3-5 · 10 ^-4 cm ^-1 ; the lifetime of the excited state of Nd ³⁺ is 180-200 Moscow time, as indirect evidence of the absence of concentration quenching of the luminescence of the active material.

The technical result is achieved by the fact that the proposed active material for a liquid laser, including neodymium ion, tin tetrachloride, phosphorus oxychloride, according to the invention, the material additionally contains triflate ion in the following ratios of components (wt.%):

neodymium ion 1,5 ÷ 7,0 tin tetrachloride 2.7 ÷ 12.0 triflate ion 2.3 ÷ 16.0 phosphorus oxychloride rest

the relative content of the neodymium ion and triflate ion is 1: 1.5 ÷ 2.2.

The concentration of neodymium ion is chosen for reasons that, at values of less than 1.5 wt.%, Only mononuclear complexes are present in the solution, and at values above 7.0 wt.%, The technical result is not achieved due to deficiency of the matrix solvent.

By triflate ion (CF ₃ SO ₃ ^- ) is meant the residue of the trifluoromethanesulfonic acid chloride formed during the preparation of the substance.

The presence of a triflate ion makes it possible to increase the concentration of the luminescent center in the liquid phase of the laser material by more than three times while maintaining a low viscosity, which testifies to the formation of island mononuclear complexes. In this case, the triflate ion promotes the formation of a favorable oxygen environment around the luminescent neodymium ion and provides a low inactive loss coefficient and the absence of concentration quenching of luminescence.

The drawing shows the dependence of the viscosity of the active material on the content of neodymium ion in solution. The prototype curve corresponds to the Nd ³⁺ - OPCI ₃ - SnCI _{4 system} without triflate ion. Curve 1 corresponds to the ratio of neodymium-ion: triflate-ion, equal to 1: 2.2. Curve 2 - the ratio of neodymium-ion: triflate-ion, equal to 1: 1.5. Curve 3 - the ratio of neodymium-ion: triflate-ion, equal to 1: 2.0.

The relative content of neodymium ion and triflate ion as 1: 1.5 ÷ 2.2 is justified by the fact that these ratios are close to stoichiometry for the formation of a monomeric complex of neodymium with the composition: [(Cl ₃ PO) ₄ Nd (CF ₃ SO ₃ ) ₂ ] SnCl ₅ .

The technology involving trifluoromethanesulfonic acid chloride is simple because it eliminates operations such as heat treatment of the reaction mixture and filtration of the final solution.

The active material for a liquid laser is prepared as follows. The reaction mixture, consisting of phosphorus oxychloride, tin tetrachloride, neodymium hydroxide and trifluoromethanesulfonic acid chloride, is loaded into a reactor equipped with a phosphoric anhydride shutter. The reaction mixture interacts smoothly with slight heating and ends with its complete homogenization. The resulting clear solution, painted in lilac color, is suitable for use.

The following are examples of achieving a technical result with various relative contents of the neodymium ion and triflate ion in the active material.

Example 1. The relative content of neodymium ion and triflate ion is 1: 2.2 at wt.% Components:

neodymium ion 1,5 ÷ 7,0 tin tetrachloride 2.7 ÷ 12.5 triflate ion 3.3 ÷ 16.0 phosphorus oxychloride rest

The viscosity values are presented in the drawing, curve 1. At a concentration of Nd ³⁺ equal to 7.0 wt.%, The viscosity reaches the maximum acceptable value of 2.5 cSt.

Example 2. The relative content of neodymium ion and triflate ion is 1: 1.5 with wt.% Components:

neodymium ion 1,5 ÷ 7,0 tin tetrachloride 2.7 ÷ 12.5 triflate ion 2.3 ÷ 10.5 phosphorus oxychloride rest

The viscosity values are presented in the drawing, curve 2. At a concentration of Nd ³⁺ equal to 7.0 wt.%, The viscosity reaches the maximum acceptable value of 2.5 cSt.

Example 3 (best result). The relative content of neodymium ion and triflate ion is 1: 2.0 with wt.% Components:

neodymium ion 1,5 ÷ 7,0 tin tetrachloride 2.7 ÷ 12.5 triflate ion 3.0 ÷ 14.0 phosphorus oxychloride rest

The viscosity values are shown in the drawing, curve 3. At a concentration of Nd ³⁺ equal to 7.0 wt.%, The viscosity is 1.4 cSt, however, a further increase in the concentration of neodymium is not achieved due to the deficiency of the matrix solvent, i.e. saturation of the solution.

The claimed active material for a liquid laser has the following spectral-luminescent characteristics:

- viscosity no more than 2.5 cSt;

- the coefficient of inactive absorption at a wavelength of 1.06 microns - within 3-5 · 10 ^-4 cm ^-1 ;

- the lifetime of the excited state of Nd ³⁺ is 180-200 Moscow time.

Claims (1)

Active material for a liquid laser, including neodymium ion, tin tetrachloride, phosphorus oxychloride, characterized in that the material additionally contains triflate ion in the following ratios of components, wt.%: Neodymium ion 1.5 ÷ 7.0 Tin tetrachloride 2.7 ÷ 12.5 Triflate ion 2.3 ÷ 16.0 Phosphorus oxychloride the relative content of the neodymium ion and triflate ion is 1: 1.5 ÷ 2.2.

Images