Er3+ emission transition occurs within this wavelength range corresponding to the 4I13/2 →4I15/2 . However, Er3+absorption itself is too weak to allow direct pumping and so, energy transfers are required. The most efficient ones are given by Yb3+ ions under absorption from the 2F7/2 → 2F5/2 transition, followed by energy transfer to the 4I11/2 Er3+ level and fast nonradiative transition to the Er3+ 4I13/2 level which emits the expected fluorescence.Er,Yb:glass laser with radiation output at the wavelength of 1540 nm does not require the addition of additional components.
As an eye-safe wavelength laser, 1540um ,Er3+/Yb3+ co-doped phosphate glass lasers have attracted much attention for their compactness and low cost, such as laser generation and signal amplification because the wavelength of 1540nm is just at the position of the eye-safe and the fiber optic communication window. 1540nm lasers have used in ranging finder, radar, target recognition. Er3+/Yb3+ co-doped phosphate glass cooperate with passive Q-Switch crystal -co:spinel to get 1540nm pulse solid-state laser.
| EAT14 | WM4 | |
| Cross section for stimulated emission (10-20cm2) | 0.8 | 0.75 |
| Fluorescent lifetime (ms)* | 7.7-8.0 | 7.7-8.2 |
| Center lasing wavelength (nm) | 1535 | 1535 |
| EAT14 | WM4 | |
| Refractive index (1535nm) | 1.524 | 1.528 |
| Refractive index (d 589.3nm) | 1.532 | 1.536 |
| Abbe value | 66 | 66 |
| dn/dT (10-6/℃) (20~100℃) | -1.72 | -3 |
| EAT14 | WM4 | |
| Transformation temp. (℃) | 556 | 530 |
| Softening temp. (℃) | 605 | 573 |
| Coeff.of linear thermal expansion (10-7/K) (20~100℃) | 87 | 82 |
| Coeff.of linear thermal expansion (10-7/K) (100~300℃) | 95 | 96 |
| Thermal Coeff.of optical path length (10-6/K) (20~100℃) | 2.9 | 1.4 |
| Thermal conductivity (25℃) (W/mK) | 0.7 | 0.7 |
| EAT14 | WM4 | |
| Density (g/cm3) | 3.06 | 2.83 |
| Chemical durability (weigh loss rate at 100℃ distilled water) (μg/hr.cm2) | 52 | 82 |
Absorption and Emission Spectrum
| Orientation Tolerance | < 0.5° |
| Thickness/Diameter Tolerance | ±0.05 mm |
| Surface Flatness | <λ/8@632 nm |
| Wavefront Distortion | <λ/4@632 nm |
| Surface Quality | 10-5 |
| Parallel | 10〞 |
| Perpendicular | 15ˊ |
| Clear Aperture | >90% |
| Chamfer | <0.1×45° |
| Maximum dimensions | dia (3-12.7)×（3-150）mm2 |
Wide absorption band
Long fluorescence lifetime
High optical quality
Safety for eye
High slope efficiency
Optical Communication
Range And Lidar