LBO crsytal (Lithium Tri-borate) is one of the most useful nonlinear optical material not just for its relatively large conversion coefficient – 3x that of KDP, but also for its excellent physical propertie
LBO Crystals
Lithium triborate (LiB₃O₅ or LBO) is an excellent nonlinear optical crystal, invented and developed by the Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences.
Advantages of LBO Crystals:
LBO Crystal is a highly versatile and widely used nonlinear optical crystal, recognized for its exceptional properties that make it ideal for various high-power laser applications, including frequency doubling and parametric oscillation.
1. Wide Transparency Range: LBO crystals have a broad optical transparency range from 160 nm to 2600 nm, covering the UV, visible, and near-infrared regions. This makes them suitable for a wide variety of laser sources.
2. Excellent Frequency Conversion Efficiency: LBO exhibits a relatively high frequency conversion efficiency, approximately three times that of potassium dihydrogen phosphate (KDP) crystals. It is particularly effective in second-harmonic generation (SHG) and third-harmonic generation (THG) for Nd:YAG, Nd:YLF, and Ti:sapphire lasers.
3. High Damage Threshold: LBO crystals can withstand high-intensity laser applications due to their impressive laser damage threshold. At 1064 nm, they can handle up to 45 GW/cm², making them ideal for high-power and ultra-fast laser systems.
4. Low Thermal Effects: Compared to other nonlinear crystals like KTP, LBO has minimal thermal lensing effects. This is crucial for maintaining beam quality in high-power operations.
5. Broad Phase Matching Capabilities: LBO supports both Type I and Type II non-critical phase matching (NCPM). Type I NCPM works within the 1000-1300 nm range, and Type II NCPM operates from 800 to 1100 nm, both at room temperature. This versatility allows LBO crystals to accommodate a variety of laser wavelengths and applications.
6. High Optical Homogeneity: LBO crystals are known for their high optical homogeneity (dn ~10-6) and are typically grown with minimal internal defects, making them suitable for precision laser applications.
7. Wide Acceptance Angle and Small Walk-Off: The large acceptance angle and small walk-off angle reduce beam quality requirements for the input laser, making alignment easier and reducing sensitivity to input beam parameters.
8. Applications in High-Power Lasers: LBO is widely used in SHG and THG processes for lasers like Nd:YAG and Ti:sapphire, as well as in Optical Parametric Oscillators (OPOs) and Optical Parametric Amplifiers (OPAs), supporting both continuous-wave and ultra-fast laser systems.
LBO crystals offer a combination of high frequency conversion efficiency, wide transparency, and superior physical robustness, making them a preferred material for advanced nonlinear optics, especially in high-power and ultra-fast laser systems.
Characteristics of LBO Crystal:
LBO crystals exhibit excellent optical quality, extremely high laser damage thresholds, and strong UV transparency, along with effective second-harmonic generation (SHG) properties. This makes LBO a valuable crystal for ultraviolet (UV) frequency doubling applications. However, the significant anisotropy in its thermal expansion coefficients along different crystal axes (ax = 10.8×10⁻⁵/K, ay = 8.8×10⁻⁵/K, xz = 3.4×10⁻⁵/K) poses challenges in processing, such as cutting, grinding, and polishing, which directly impact the final quality and lifespan of the device.
The processing steps include directional cutting, rough shaping, grinding, and polishing. Due to the large variations in thermal expansion along different crystal directions, each step must minimize mechanical stress-induced damage. For cutting, the feed rate and coolant oil temperature need to be controlled to avoid crack formation caused by excessive speed. Rough grinding removes surface marks and damage layers left by cutting, while ensuring surface precision for subsequent stages.
LBO Crystal Physical Property
| Chemical Formula | LiB3O5 |
| Crystal Structure | Orthorhombic, mm2 |
| Cell Parameters | a = 8.4473, b = 7.3788Å, c = 5.1395Å, Z = 2 |
| Melting point | 834°C |
| Optical homogeneity | d n ~ 10-6/cm |
| Mos hardness | 6 |
| Density | 2.47 g/cm3 |
| Absorption coefficient | < 0.1%/cm (at 1064 nm and 532 nm) |
| Specific heat | 1.91J/cm3xK |
| Hygroscopic susceptibility | low |
| Thermal expansion coefficients | a, 4 x 10-6/K; c, 36 x 10-6/K |
| Thermal conductivity | ^ c, 1.2 W/m/K; //c, 1.6 W/m/K |
Linear Optical Properties
| Transparency range | 1 60-2600 nm |
| Refractive indices: at 1064 nm at 532 nm at 355 nm | nx = 1.5656, ny = 1.5905, nz = 1.6055 ne = 1.5785, no = 1.6065, nz = 1.6212 ne = 1.5971, no = 1.6275, nz = 1.6430 |
| Therm-optic coefficients | dno / dT = -9.3 x 10-6/°C dne / dT = -16.6 x 10-6/°C |
| Sell Meier Equations (l in mm) | |
no2 (l) = 2.7359 – 0.01354l2+ 0.01878/(l2-0.01822) | |
Nonlinear Optical Properties
| Phase-matchable output wavelength | 554 – 2660 nm (type I), 790 – 2150 nm (type II) |
| NLO coefficients | d33 = 0.06; d32 = 1.2; d22 = 1.1 |
| Walk-off Angles(@ 1064 nm) | 0.4° (Type I SHG), 0.3° (Type II SHG) |
| Acceptance Angles(@1064 nm) for SHG Type I | 9.6(mrad-cm) CPM at 25°C 248(mrad-cm) NCPM at 150°C |
| Electro-optic coefficients | g 11 = 2.7 pm/V, g 22, g31 < 0.1g11 |
| Conversion Efficiency | >90% (1064 -> 532nm) Type I SHG |
| Damage threshold at 1064 nm at 532 nm at 355 nm | 45 GW/cm2 (1 ns); 10 GW/cm2 (1.3 ns) 26 GW/cm2 (1 ns); 7 GW/cm2 (250 ps) 22 GW/cm2 |
Lithium Tri-borate Crystal Specifications
| Thin crystals: (5-10) x (5-10) x (0.01-3) mm3 |
| Regular sizes: 2 x 2 mm2 to 30 x 30 mm2 in cross-section, up to 60 mm in length |
| Absorption: < 20ppm (0.00002%) @1064 |
| S/D of 0/0 for cross-section: up to 5 x 5 mm |
| Different cuts, sizes and AR coatings are available upon request. |
Nonlinear LBO crystals, LBO crystal have wide transparency region, Broad type 1 and type 2 NCPM, small walk-off angle and high damage threshold.
LBO Crystal is a non-linear optics crystal, owns LBO crystal’s production capability in our modern workshops.
lbo crystals
A-Star LBO crystal Workshop
LBO crystal by Cristal Laser manufacturer
LBO crystal (Lithium Triborate – LiB3O5) has become the material of choice for high power laser applications from the UV to NIR.
Nonlinear LBO crystals, LBO crystal have wide transparency region, Broad type 1 and type 2 NCPM, small walk-off angle and high damage threshold.
Lithium Tri-borate Crystal
It is unique in many aspects, especially its wide transparency range, moderately high non-linear coupling, high damage threshold and good chemical and mechanical properties. Its transmission range is from 0.16m to 2.6m.
LBO crystals allows temperature-controllable non-critical phase-matching (NCPM) for 1.0-1.3 m, Type I SHG, and also provides room temperature NCPM for Type II SHG at 0.8-1.1 m. It possesses a relatively large angular acceptance bandwidth, reducing the beam quality requirements for source lasers.
Nonlinear LBO crystals, LBO crystal have wide transparency region, Broad type 1 and type 2 NCPM, small walk-off angle and high damage threshold.
Tag:LBO, nonlinear, high damage threshold, frequency doubling, high power lasers, crystal LBO, Crystals,nonlinear and laser crystals, crystal, lbo, second harmonic generation, lithium triborate.
LBO Features
Wide transmission region from 160 nm to 2600nm
Large effective second-harmonic-generation (SHG) coefficient (about three times that of KDP)
Good mechanical and physical properties
High damage threshold of 18.9 GW/cm2 for a 1.3 ns laser at 1053 nmv
Both Type I and II NCPM in a wide wavelength range is possible
Wide acceptance angle and small walk-off
High optical homogeneity with δn≈10-6/cm
Spectral NCPM near 1300 nm
LBO Crystal Applications
Frequency doubling and tripling of Nd:YAG and Nd:YLF lasers.
SHG and THG for middle and high power Nd: lasers at 1064 nm for medical, industrial and military applications
SHG and THG of high power Nd: lasers at 1342 nm & 1319 nm for red and blue laser
Optical parametric amplifiers (OPA) and oscillators (OPO) pumped by Excimer lasers and harmonics of Nd:YAG lasers.
Optical parametric chirped pulse amplification (OPCPA) in ultrafast pulse system