New laser crystals of double halogenides

MPb2X5

MPb₂X₅ ( M=K, Rb X= Cl, Br): RE

R&D possibilities

Crystals of group MPb₂X₅ ( M=K, Rb X= Cl, Br): RE is a new promising active media for lasers, operating on different wavelengths in the range from UV to mid-IR, including those for TV amplifiers with diode pumping. Interest to this material, which has high RE segregation coefficients and a set of attractive properties increased considerably to date.

Main characteristics of MPb₂X₅

		KPb2Cl5	RbPb2Cl5	KPb2Br5	RbPb2Br5
Transparency range, µm		0.3 – 20	0.3 - 20	0.3 - 30	0.3 - 30
Space group		P22/c	P22/c	P22/c	l4mcm
Melting temperature, °C		434	423	382	382
Density, G/cm3		4.629	5.041	5.619	5.83
Reflection Index (632.8 nm)		2.019	2.019	2.2	2.2
Thermal conductivity, W/m*K		4	4	-	-
Mohs hardness		2,5	2,5	2,5	2,5
Phonon energy, cm-1		203	203	133	133
Lattice parameters
	a, Å	8.854(2)	8.959	9.256(2)	8.41
	b, Å	7.927(2)	7.973	8.365(2)	8.365(2)
	c, Å	12.485(3)	12.493	13.025(3)	14.5
	(deg)	90.05(3)	90.12	90.00(3)	90.00(3)
	V	876.3(4)	895.3	1008.4(4	1025.6
	Z	4	4	4	4
		Chemical stability		Chemical stability

Low energy of phonons in halogenides provides mainly radiative transitions between adjacent levels with the gap Δ Е ≥ 1500 cm-: as a result emission bands cover the wide spectral region from UV (transitions from upper excited levels) to 9-10 µm in the mid-IR (transitions within both excited and ground RE multiplets);

Complex of long decay times for lower states, high values of absorption cross-sections and low rates of the nonradiative multiphonon relaxation makes these crystals promising for their application as active media for UV/VIS lasers with up-conversion pumping;

It is important that intense absorption bands match the laser diodes emission for many RE ions in MPb₂X₅ crystals.

Rare – earth ion		Pr	Nd	Dy [19]	Er	Yb [19]	Ym	Ho
Maximum peak Absorption cross section, δρ (λ max), 10-20 cm2		10.9	14.9	51.8	21.5	1.78	2.85	11.0
Wavelength (λ max), nm		487	589	129.7	379.4	982	797.9	453
Peak absorption cross section for LD pumping δρ (λ max), 10-20 cm2		-	6.22	0.9	4.8	1.78	-	-
Wavelength (λ), nm		-	808.2	810.4	982.6	982	800	900

Using the MPb₂X₅ ( M=K, Rb X= Cl, Br) : RE one can create lasers with diode laser pumping, where different mechanisms of energy transformation, including those with simultaneous and cascade generation, with minimum Stoke's losses, are realized;

Relatively broad, structureless luminescence bands in MPb₂X₅ ( M=K, Rb X= Cl, Br): RE crystals allow fine tuning of the stimulated emission frequency;

To date stimulated emission has been obtained for 1.064 µm (Nd), 2.4 µm (Dy) and 4.3 µm (Er)

We suggest the MPb₂X₅ ( M=K, Rb X= Cl, Br) : RE crystals for joint investigation of the stimulated emission using different schemes;

Variation of RE type and dopant concentration are possible for Variation of RE type and dopant concentration are possible for MPb₂X₅ (M=K, Rb; X=Cl, Br):RE crystals

Typical sizes of optical elements are 4x4x5 (15) mm³;

Protective/antireflection coatings may be performed on the aperture surfaces of the produced elements.

Application

• Active media for lasers, laser amplifiers.
• We are opened for a joint research proposals in crystal growth, as well as an investigations of a new materials

We are able to provide suitable Anti-reflection / Protective, etc. coatings tailored to customer’s specifications, reflectivity curves are applied upon request.