The characteristics needed to enable laser emission in the visible spectral range are rare in laser materials. Protactinium doped yttrium lithium fluoride (Pr:YLF) crystals are a promising laser material for intracavity generation of second harmonics for direct visible laser generation and direct UV laser generation. Among them, Pr3+ is an interesting laser ion for solid-state lasers in the visible spectral range because its energy level scheme offers green (523 nm, 3P0 to 3H5), red (640 nm, 3P0 to 3F2), orange (607 nm, 3P0 to 3H6), and dark red (720 nm) spectral regions.
Alfa Chemistry is an expert in customizing laser crystals, and they will gently and meticulously walk customers through the Pr3+:YLF laser crystal customization procedure online. We grow the Pr:YLF laser crystals by the Czochralski method.
Advantages of Pr:YLF Crystals
The Pr:YLF laser crystal has a large cross-section (~10-19 cm2) for both absorption and emission. Its absorption band in the blue spectral region has a good overlap with the emission of InGaN laser diodes and 2ω-OPSL. Diode-pumped solid-state lasers made from Pr:YLF crystals can be applied to science, entertainment, and the precise and effective processing of metals like copper or gold.
Fig 1. Absorption spectrum of the 5 mm long Pr:YLF crystal (0.5 at. %) at room temperature, along with the emission spectrum of the pump diode. (Liu Z, et al. 2013)
Properties of Pr:YLF Crystals
| Optical and Physical Properties | |
|---|---|
| Crystal Structure | Tetragonal |
| Lattice Parameter | a=5.16 Å, c=10.732 Å |
| Density | 3.95 g/cm3 |
| Melting Point | 819 ℃ |
| Mohs Hardness | 5 |
| Thermal Conductivity | 6 W·m-1·K-1 |
| Thermal Expansion Coefficients | ~16×10-6 K-1 |
| Refractive Index | (@1064 nm) no=1.448, ne=1.470 |
| dn/dT | -5.2×10-6 (||c) K-1, -7.6×10-6 (||a) K-1 |
| Absorption Peak Wavelength | 444 nm |
| Emission Cross Section | 20×10-20 cm2 |
| Absorption Bandwidth at Peak Wavelength | ~5 nm |
| Absorption Cross Section at Peak | 8×10-20 cm2 |
| Laser Wavelength | 523 nm, 607 nm, 639 nm, 698 nm, 721 nm |
| Alfa Chemistry offers Pr:YLF specification | |
| Dimension | Upon customer request |
| Dimension Tolerance | diameter +0.0/-0.05 mm, Length ±0.1mm |
| Doping(atm%) | 0.1% ~ 2% |
| Orientation | a-cut / c-cut crystalline direction |
| Flatness | λ/10 @ 632.8nm |
| Surface Quality | 10/5 Scratch/Dig MIL-O-1380A |
| Clear Aperture | > 90% |
| Damage Threshold | 750MW/cm2 at 1064nm, TEM00, 10ns, 10Hz |
| Coating | AR/HR/PR coating upon customer's request |
| Quality Warranty Period | One year under proper use |
Why Choose Alfa Chemistry?
Pr:YLF crystals are grown by Alfa Chemistry using CZ growing procedures. To guarantee that each crystal meets the requirements of the customer and performs well, we employ high-quality starting materials for crystal growth, whole ingot interferometry, He-Ne lasers for precise inspection of scattered particles in the crystal, and spectrophotometers for precise measurement of volume loss.
The temperature effect of the gain medium is one of the primary limiting factors in high-power Pr:YLF solid-state lasers. By simulating the temperature distribution, thermal stress, thermal focal length, and pump polarization effects of Pr:YLF crystals, we conduct a theoretical examination of the thermal effects of these materials.
Fig 2. Thermal effect of Pr:YLF crystal was analyzed: (a) The influence of crystal length on thermal focal length; (b) The relationship between temperature gradient and crystal doping concentration; (c) The effect of pump polarization component on radial and tangential thermal stress. (Qi Y, et al. 2021)
If you need technical advice, please contact our technical team to learn more about our high-quality services.
References
- Liu Z, et al. (2013). "Diode-Pumped Pr3+:LiYF4 Continuous-Wave Deep Red Laser at 698 nm." Journal of the Optical Society of America B. 30(2): 302-305.
- Qi Y, et al. (2021). "High-Energy, Nanosecond Orange Laser at 604 nm Based on Pr:YLF Crystal at Room Temperature." Results in Physics. 26: 104382.