NAP Neodymium-doped phosphate glass is created specially for high average power applications. NAP2 and NAP4 are two types of new laser glass with high thermal shock resistance properties, which have higher thermal conductivity, lower coefficient of thermal expansion and modest emission cross section. They are served for laser systems with high repetition rates and high energy rates and high energy, which have broad applications in laser ranger, laser peening and pump laser for OPCPA systems.
| NAP2 | NAP4 | |
| Cross section for stimulated emission(10-20cm2) | 3.6±0.1 | 3.1±0.1 |
| Lifetime at 1053nm (μsec)* | ≥360(Nd2O3：0.5wt%) | ≥370(Nd2O3：0.5wt%) |
| ≥350(Nd2O3：1.0wt%) | ≥360(Nd2O3：1.0wt%) | |
| ≥330(Nd2O3：2.0wt%) | ≥330(Nd2O3：2.0wt%) | |
| ≥310(Nd2O3：3.0wt%) | ≥310(Nd2O3：3.0wt%) | |
| Effective bandwidth (nm) 25.4 28.5 | 25.4 | 28.5 |
| Fluorescence peak wavelength (nm) | 1052 | 1052 |
| Absorption coefficient (cm-1) | ≤0.0015(1053nm) | ≤0.002(1053nm) |
| ≤0.25(400nm) | ≤0.3(400nm) | |
| ≤1.5(3333nm) | ≤1.5(3333nm) |
| NAP2 | NAP4 | |
| Non-linear refractive index coeff.n2(×10-13e.s.u) | ≤1.25 | ≤1.10 |
| Refractive index (1053nm) | 1.537±0.003 | 1.515±0.005 |
| Abbe value | 67 | 67 |
| dn/dT (10-6/℃) (20~100℃) | -9 | 1.9 |
| NAP2 | NAP4 | |
| Transformation temp. (℃) | 500 | 545 |
| Softening temp. (℃) | 550 | 600 |
| Coeff.of linear thermal expansion (10-7/K) (30~100℃) | 87 | 63 |
| Thermal coeff.of optical path length(10-6/K) (50~100℃) | 3.8 | 5 |
| Thermal conductivity (25℃) (W/mK) | 0.76 | 0.88 |
| Specific heat (25℃) (J/gK) | 0.757 | 0.775 |
| NAP2 | NAP4 | |
| Density (g/cm3) | 2.84 | 2.58 |
| Young’s modulus (G Pa) | 58 | 67 |
| Posson’s ratio | 0.25 | 0.25 |
| Knoop hardness (kg/cm2) | 382 | 549 |
| Fracture toughness (MPa·m1/2) | 0.68 | 0.74 |
| Dw (H2O 98℃) (mg/(cm2/day)) | 0.003 | 0.002 |
High thermal shock resistance properties
Higher thermal conductivity
Lower coefficient of thermal expansion
Modest emission cross section
High average power laser
Laser ranger
Pump laser