The crystals of holmium-doped yttrium lithium fluoride (Ho:YLF) make an excellent laser material. Its highest laser energy level has a larger emission cross section and a lifetime that is significantly longer than Ho:YAG (about 14 ms). Additionally, Ho:thermal YLF's lens is substantially weaker, which aids in producing diffraction-limited beams despite vigorous end-pumping. Alfa Chemistry is an expert customizer of laser crystals and will patiently and carefully guide customers through the online customization process for Ho:YLF laser crystals. Alfa Chemistry produces Ho:YLF laser crystals using Czochralski technique.
Advantages of Ho:YLF Crystals
Ho:YLF crystals, a naturally birefringent substance that directly pumps Ho 5I7, have the main benefit of not requiring energy transfer, which can result in a variety of radiative and non-radiative losses. Ho:YLF crystals have a long-lived 5I7 energy level, which produces outstanding Q-modulation performance.
The customer creates a controllable mid-infrared light source by using Ho:YLF laser crystals as a gain medium with a wavelength of 2000 nm. Due to its quick identification of volatiles in the molecular fingerprint region, this light source is crucial for military applications, high-sine wave generation, and strong-field physics research.
Fig 1. Absorption spectra of Ho:YLF. (Strauss H. J, et al. 2011)
Advantages:
- Longer upper laser energy level lifetime ~ 15 ms
- Higher emission cross section
- Weak thermal lensing due to low dn/dT values
- Efficient Q-switching operation (up to 37 mJ per pulse)
Properties of Ho:YLF Crystals
| Optical and Physical Properties | |
|---|---|
| Crystal Structure | Tetragonal |
| Typical Doping Level | 0.5~1% |
| Density | 3.95 g/cm3 |
| Melting Point | 819 ℃ |
| Mohs Hardness | 5 |
| Thermal Conductivity | 6 W·m-1·K-1 |
| Thermal Expansion Coefficients | 10.1×10-6 (||c) K-1, 14.3×10-6 (||a) K-1 |
| Refractive Index | (@1064 nm) no=1.448, ne=1.470 |
| dn/dT | -4.6×10-6 (||c) K-1, -6.6×10-6 (||a) K-1 |
| Absorption Peak Wavelength | 1940 nm |
| Emission Cross Section | 1.8×10-20 cm2 |
| Absorption Bandwidth at Peak Wavelength | ~18 nm |
| Absorption Cross Section at Peak | 1.2×10-20 cm2 |
| Laser Wavelength | 2060 nm |
| Alfa Chemistry offers Ho:YLF specification | |
| Dimension | Upon customer request |
| Dimension Tolerance | Diameter +0.0/-0.05 mm, Length ±0.1mm |
| Doping(atm%) | 0.5% ~ 1% |
| 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?
The CZ growing method is used by Alfa Chemistry to grow Ho:YLF crystals. To guarantee that every crystal satisfies customer requirements and works effectively, we use high-quality starting materials for crystal growth, bulk ingot interferometry, accurate inspection of scattered particles in crystals using He-Ne lasers, and precise volume loss measurement using spectrophotometers.
Fig 2. Experimental setup of Q-switched Ho:YAG laser. (Wang Y.P, et al. 2018)
If you need technical advice, please contact our technical team to learn more about our high-quality services.
References
- Strauss H. J, et al. (2011). "Ho:YLF & Ho:LuLF Slab Amplifier System Delivering 200 mJ, 2 μm Single-Frequency Pulses." Optics Express. 19(15): 13974-13979.
- Wang Y.P, et al. (2018). "A Q-Switched Ho:YAG Laser with Double Anti-Misalignment Corner Cubes Pumped by A Diode-Pumped Tm:YLF Laser." Infrared Physics & Technology. 91: 8-11.