LASER Product Brochure MATERIALS Neodymium …

1 LASERMATERIALSCORPORATIONP roduct BrochureNeodymium YAGFor more information, visit our web about our Nd:YAG LASER crystal products LASER Rod Specifications Ordering InformationInformation about Nd:YAG & crystal growth Nd:YAG Production at LMC Notes about Nd Concentration Properties of Nd:YAGL aser MATERIALS Corporation produces Nd:YAG boules,fabricated LASER rods and slabs. Our crystal growthfacility in Vancouver, Washington exclusively produceslarge diameter boules (currently, 82 mm) in lengthsup to 250 mm while retaining acceptable Neodymiumconcentration levels. As a crystal grower, we concen-trate on developing and improving the crystal growthprocess to produce high yields and consistently highmaterial quality. Pure raw MATERIALS , precise formula-tion, and exacting growth control are the keystones ofour drilling a 5 mm rod from a 75 x 208 mm boule section Better than pure yttrium and aluminum oxides, and Neodymium oxide are used.

2 Pure or better shield gases are used throughout the crystalgrowth process. All raw MATERIALS are stored and prepared in a clean environment. Constituent powders are thoroughly dried in high temperature ovens toreduce hydroxyl impurities. The dried raw MATERIALS are carefully weighed on precision balances toinsure precise stoichiometry and dopant concentration. Computer control of the growth process and associated facilities pro-duces the stable conditions required for consistent boule growth;cooling water and room air temperatures are maintained to withinclosely controlled tolerances. Crystal growth control is based on weight gain for the most consistentboule diameter :YAG Production 75 x 208 mm boule section(Nd:YAG, atom % Nd concentration) LASER rod "blanks" are extracted from completed boulesusing a diamond core drill; for slabs, a slicing saw is used tocut out the rough rectangular shape.

3 In either case, therough finished blanks are then sent out for the finishingoperations of precision grinding to final size, polishing, andanti-reflection coating. You have the option of purchasingfinished rods directly from us or purchasing unfinished"blanks" and using the fabricator of your :YAG Crystal GrowthGrowth of Neodymium doped yttrium aluminum garnet (Nd:YAG) crystals by the Czochralski technique is the methodof choice for virtually all commercially available Nd:YAG. This is a time consuming process requiring carefulcontrol of the growth environment over a period of 4 to 5 weeks just to produce one crystal boule. Still, theCzochralski method has proven to be the only acceptable way to produce Nd:YAG with sufficient optical clarity andhomogeneity for use in a LASER quality Vs. Boule sizeOne of the most important advances in Nd:YAG production in recent years has been the trend toward larger diameter strain in the grown boule is the principle cause of optical distortion in finished LASER rods more than a few tens ofmillimeters in length (in shorter rods, the quality of the end finish is more important).

4 Larger boules have significantly lowerstrain levels over much of their cross section resulting in significantly lower optical distortion in finished additional advantage of larger boules is reduced cost. The cross-sectional area is increased while the linear growth rateremains comparable, resulting in an increased rate of material growth. At large diameters, Nd:YAG is more sensitive to processparameter fluctuations and obtaining high yields of good Product is more difficult. But as a result of improved controlelectronics and computerization of the growth process, growth rate fluctuations can be maintained well within tolerance toprovide high yields of good Product at large ConcentrationIn Neodymium doped yttrium aluminum garnet, Neodymium substitutes for yttrium in the crystal lattice. However, becauseneodymium is larger than yttrium, this substitution does not occur readily.

5 In fact, the concentration of Neodymium in thecrystal is only a small fraction of its concentration in the melt. Since the growing crystal is continually rejecting Neodymium ,the concentration of the melt (and hence the crystal) increases as the growth progresses. To minimize this effect it is necessaryto use a large crucible and to pull only a small fraction (typically20-30%) of the total material available. The upper graph showshow the concentration of Neodymium increases as a function ofmelt fraction LASER MATERIALS Corporation, we grow boules at two average Ndconcentrations: Nd and Nd. The Nd concentrationprofile for each is illustrated in the lower graph. The composi-tion is engineered to provide the specified average concentrationin 200 mm lengths. Lengths up to 250 mm can be provided withslightly higher average Nd material less than 200 mm, the average concentration willvary depending on from where in the boule the material is individual LASER rod we ship is supplied with data includingthe average Nd concentration and the change in concentrationover the rod's length.

6 Standard tolerances for various rod lengthsare listed on our LASER rod specification should be noted that the absolute accuracy of the neodymiumconcentration must take into how accurately the distributioncoefficient (ratio of dopant concentration in the crystal to that inthe melt) is known. At LASER MATERIALS Corporation our formula-tions are based on a value of , which is consistent withindustry practice and most determinations in the [Nd] (atom %)net boule length (mm) [Nd] (atom %)fraction of melt pulled12706 NE 95th St., #102 Vancouver WA : (360) 254-4180 FAX: (360) System Four LevelLasing Upper State 4F3/2 Fluorescent Lifetime 230 sMain Pump Bands & m4F3/2 4I11/2 Stark Level Transitions:Relative LaserTransitionWavelength ( m) PerformanceR2 (Principle)R1 4I13/2 Stark Level Transitions:Relative LaserTransitionWavelength ( m) PerformanceR2 otherwise noted, data is for 1% Nd (atomic) at 300K.

7 Formore information, consult the following references from which theabove data was Koechner, Solid-State LASER Engineering-Third CompletelyRevised and Updated Edition (Springer-Verlag, Berlin, Heidelberg1992)Alexander A. Kaminskii, LASER Crystals-Their Physics and Proper-ties, Second Edition (Springer-Verlag, Berlin, Heidelberg, 1990)CRC Handbook of LASER Science and Technology, Volume V,Optical MATERIALS , Part 3: Applications, Coatings, and Fabrica-tion, Marvin J. Weber Ed. (CRC Press, Boca Raton, FL 1987)LASERCORPORATIONMATERIALS Copyright 1995--1999electronic versionNd:YAG Material PropertiesChemical/PhysicalChemical Formula Weight System/Structure Cubic/GarnetSpace Group Oh10-Ia3dLattice Constant Melting Point 1950 20 CDensity (Knoop) 1350 35 of Elasticity (E) 310 GPa (45 x 106 psi)Poisson's Ratio ( ) Strength ( t) 175-200 MPa (25-30 x 103 psi)ThermalSpecific Heat Capacity (Cp) Conductivity (k) Expansion Coef.

8 ( ) 7 x 10-6 K-1 Thermal Shock Parameter (R) 7-8 the Thermal Shock Parameter, the fracture limit for ther-mal dissipation in a CW LASER rod can be calculated:For rods it is independentof rod diameter (= 8 R) 175-200 slabs it is dependent onthe aspect ratio (= ).For a 4:1 aspect ratio (=48R) 330-390 : These values are absolute maxima and can begreatly affected by surface finish, fixturing, Index (n) at mTemperature Coef. (dn/dT) x 10-6 K-1 Wavelength m m m m m Coefficients:P11 :YAG LASER RodsCoatingsCoatingsCoatingsCoatingsCoat ingsTypeReflectivityDamage ThresholdDamage Threshold%R per Surface(20nS Pulse, )(CW, )AR Reflecting95 to 99 > >25 Partially Reflecting90 to 95 1> >25 Partially Reflecting10 to 90 3> >255' AL+ x 45 m10/5 scratch/dig A 10" A5 <111> (Crystal)D+ Standard Grade Premium GradeStandard [Nd]= Atom% Low [Nd]= Atom%LDExtinc.

9 Ratio Wave. Error Extinc. Ratio Wave. Error Tolerance of [Nd] Over Tolerance of [Nd] Overmmmm(dB)( )(dB)( )Average [Nd]Rod LengthAverage [Nd]Rod Length503<.19<.13504>25<.21>30<.15 .. <.24<.16653<.20<.14604>24<.22>29<.15 .. <.26<.17753<.21<.15754<.24<.17755>23<.28>28<.18 .. <.31<. <.32<.21758<.38<.241004<.28<.181005<.32<.211006>22<.36>27<.23 .. <.37<.241008<.44<.281255<.36<.231256<.41<. >21<.43>26<.27 .. <.51<. <.59<. <.48<.301508>20<.58>25<.35 .. <.67<.402008<.71<. >19<.82>24<.49 .. <.86<.512508<.84<. >18<.98>23<.57 .. < <.60 Revised specifications effective 30-April-2001 Revised specifications effective 30-April-2001 Revised specifications effective 30-April-2001 Revised specifications effective 30-April-2001 Revised specifications effective 30-April-2001 LASERMATERIALSCORPORATION Copyright 1993-2001electronic versionTo request a quote, you can call or FAX us with your requirements at the numbers below.

10 Or, click thishyperlink to go to an online quote request form at the LASER MATERIALS Corporation web EndRadiused EndRadiused EndRadiused EndRadiused EndR (m) ..510 1 Wedged EndWedged EndWedged EndWedged EndWedged EndA30' 10'1 10'2 10'6 10'8 10'Note: if both ends wedged parallel,A-B angle < 10"Brewster EndBrewster EndBrewster EndBrewster EndBrewster End% Reflectivity = .06% for planepolarized incident beam at limitof angle NumberingPart NumberingPart NumberingPart NumberingPart NumberingR5' A A AIncident Beam61 12' (Brewster's Angle)28 48' 30'[Atom % Nd]NY[P] [Diameter (mm)] [Length (mm)] [A-End/B-End] [A-Coating/B-Coating] standard grade Nd:YAG , D= L=100 mm, both ends angled 1 parallel, and an AR coating onboth Reflection ------ AHigh Reflection ------ HPartial Reflection ---- P(%R)None------------------- NFlat -------- FRadiused -- R+RadiusWedged --- W+AngleBrewster -- BSpecial ---- SUnfinished NPremium --- PStandard --- 11 Note:Indicate anti-parallelwedged ends by a negativeangle on one endOrdering Information12706 NE 95th St.