Neodymium-doped Yttrium Lithium Fluoride (Nd:YLF) is a well-established solid-state laser crystal valued for its distinct emission wavelengths, low thermal lensing, and excellent pulse performance. Compared with Nd:YAG, Nd:YLF offers reduced thermal birefringence and naturally polarized output, making it particularly suitable for short-pulse, Q-switched, and precision laser systems.
Key Properties of Nd:YLF
- Dual Emission Wavelengths: 1047 nm (π-polarized) and 1053 nm (σ-polarized) are widely used in scientific, medical, and ranging applications.
- Excellent Pulse Characteristics: Long fluorescence lifetime and low thermal lensing support short pulses with high peak power.
- Low Thermal Lensing Effect: Lower dn/dT compared to YAG-based crystals helps maintain beam quality in pulsed operation.
- High Diode-Pump Compatibility: Efficient absorption near 792–797 nm enables compact, diode-pumped laser designs.
Typical Applications
- Precision Material Processing: Fine cutting, drilling, and marking where minimal heat-affected zones are critical.
- Medical & Dental Lasers: Dermatology, dentistry, and minimally invasive treatments requiring controlled pulses.
- Scientific & Research Lasers: Pump-probe experiments, spectroscopy, nonlinear optics, and laboratory systems.
- Laser Ranging & LiDAR: Short, high-energy pulses for high-resolution range finding and LiDAR systems.
Shape Optics Supply Capability
Available Dopants
-
Nd: 0.4% – 1.2% (atomic %)
-
Er: 0.5% – 3.0% (molar %)
Dimensions
-
Rod Diameter: 1 mm – 25.4 mm
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Length: 1 mm – 180 mm
Coatings
AR, HR, or custom coatings available upon request
Standard Optical & Mechanical Specifications
| Parameter | Specification |
|---|---|
| Dopant Concentration Tolerance | ±0.1% |
| Parallelism | < 10 arc seconds |
| Perpendicularity | < 5 arc minutes |
| Chamfer | 0.1 mm × 45° |
| Clear Aperture | ≥ 95% |
| Scratch & Dig | 10/5 |
| Surface Flatness | λ/10 @ 633 nm |
| Wavefront Distortion | λ/10 @ 633 nm (Ø < 7 mm) λ/8 @ 633 nm (Ø ≥ 7 mm) |
| Damage Threshold | > 15 J/cm² (TEM₀₀, 10 ns, 10 Hz) |
Optical Properties
| Property | Value |
|---|---|
| Peak Emission Cross Section | 1.81 × 10⁻¹⁹ cm² @1047 nm (E ‖ a-axis) 1.2 × 10⁻¹⁹ cm² @1053 nm |
| Transparency Range | 0.18 – 6.7 µm |
| Fluorescence Lifetime | 485 µs (1% Nd) |
| Scatter Loss | < 0.2% |
| Peak Absorption Coefficient (1.2% Nd) | 3.59 cm⁻¹ @797 nm (E ⟂ c-axis) 10.8 cm⁻¹ @792 nm (E ‖ c-axis) |
Thermo-Optic Coefficient (dn/dT)
| Wavelength | E ⟂ c-axis | E ‖ c-axis |
|---|---|---|
| 436 nm | −0.54 × 10⁻⁶ /°C | −2.44 × 10⁻⁶ /°C |
| 578 nm | −0.91 × 10⁻⁶ /°C | −2.86 × 10⁻⁶ /°C |
| 1064 nm | −2.00 × 10⁻⁶ /°C | −4.30 × 10⁻⁶ /°C |
Low dn/dT contributes to reduced thermal lensing in pulsed laser operation.
Refractive Index (Nd:YLF)
| Wavelength | nₒ | nₑ |
|---|---|---|
| 262 nm | 1.485 | 1.510 |
| 350 nm | 1.473 | 1.490 |
| 525 nm | 1.456 | 1.479 |
| 1050 nm | 1.488 | 1.470 |
| 2065 nm | 1.442 | 1.464 |
Sellmeier Equations (YLF)
Ordinary Ray (nₒ): nₒ² = 1.38757 + 0.70757λ² / (λ² − 0.00931) + 0.18849λ² / (λ² − 50.99741)
Extraordinary Ray (nₑ): nₑ² = 1.31021 + 0.84903λ² / (λ² − 0.00876) + 0.53607λ² / (λ² − 134.9566)
(λ in µm)
Physical Properties
| Property | Value |
|---|---|
| Chemical Formula | LiY₁₋ₓNdₓF₄ |
| Crystal Structure | Tetragonal |
| Lattice Constants | a = 5.16 Å, c = 10.85 Å |
| Nd Concentration | ~1.4 × 10²⁰ cm⁻³ (1% Nd) |
| Density | 3.99 g/cm³ |
| Melting Point | 819 °C |
| Knoop Hardness | 300 kg/mm² |
| Thermal Expansion | 8.3 × 10⁻⁶ K⁻¹ (‖ c-axis) |
| Thermal Conductivity | 0.063 W·cm⁻¹·K⁻¹ |
| Specific Heat | 0.79 J·g⁻¹·K⁻¹ |
Laser System Compatibility
Nd:YLF is widely used in:
- Diode-pumped solid-state lasers
- Q-switched and pulsed lasers
- Precision and low thermal-distortion systems
Shape Optics supplies Nd-, Pr-, Er-, Tm-, Ho-doped and undoped YLF crystals, fully customizable to your design requirements.