Er:YAG Laser Crystal
Er:YAG Laser Crystal for 2940 nm Medical and Dental Lasers
Er:YAG laser crystal, also known as erbium-doped yttrium aluminum garnet, is a solid-state laser gain medium used for emission around 2940 nm. This mid-infrared wavelength is strongly absorbed by water, which makes Er:YAG crystal widely used in medical lasers, dental lasers, dermatology systems, aesthetic laser equipment, and precise surface ablation research.
ATR Crystal supplies Er:YAG crystals in rod, slab, and custom geometries for research, prototype development, and OEM laser systems. Dopant concentration, crystal orientation, dimensions, polishing, coating, surface quality, and inspection requirements can be reviewed according to your cavity design, pump configuration, cooling method, and output target.
For related laser materials, review our laser crystal category, Nd:YAG laser crystal, Yb:YAG laser crystal, Cr:YAG passive Q-switch crystal, and Nd:YVO4 laser crystal.
Er:YAG is selected for 2940 nm laser systems where water absorption, surface ablation or medical laser performance is the main requirement. If you are comparing Er:YAG with Nd:YAG, Yb:YAG or other laser crystals for a custom project, review our laser crystal selection guide before finalizing the specification.
Applications of Er:YAG Crystal
Medical laser systems for controlled tissue ablation
Dental laser systems and hard-tissue interaction research
Dermatology, aesthetic, and skin resurfacing equipment
2940 nm mid-infrared solid-state laser sources
Water-absorption surface processing and ablation studies
Research laser cavities, prototypes, and OEM gain modules
Advantages of Er:YAG Laser Crystal
- 2940 nm emissionEr:YAG emits near 2940 nm, a wavelength strongly absorbed by water and widely used in medical, dental, and surface ablation laser systems.
- Stable YAG hostThe YAG host provides good mechanical strength, thermal behavior, and mature processing routes for solid-state laser components.
- Custom Er doping20at% and 50at% Er doping options can be reviewed according to cavity design, pump conditions, and target output.
- Rod and slab formatsRods, slabs, and drawing-defined geometries can be supplied for different pump layouts and thermal designs.
- Coating supportAR coating at 2940 nm and other coating requirements can be discussed according to your optical design.
- Engineering reviewOrientation, tolerance, surface quality, flatness, coating, damage threshold, and acceptance criteria can be reviewed before production.
Specifications of Er:YAG Laser Crystal
The following values are typical Er:YAG laser crystal specifications for engineering review. Final specifications should be confirmed according to drawing, coating, quantity, and test requirements.
| Parameter | Typical Value / Option |
|---|---|
| Dopant concentration | 20at% and 50at% |
| Orientation | [100] within 5 degrees |
| Wavefront distortion | <= 0.125 lambda/inch at 1064 nm |
| Optical quality | Interference fringes <= 0.125/inch |
| Extinction ratio | Dia. 3-6.35 mm: >= 28 dB; dia. 7-10 mm: >= 25 dB |
| Rod size | Dia. 3-10 mm x 30-180 mm length |
| Slab size | 3-12 mm x 6-24 mm x 60-180 mm length |
| Custom size | Available upon customer request |
| Diameter tolerance | +0.00/-0.05 mm |
| Length tolerance | +/-0.5 mm; chamfer <0.15 +/-0.05 mm at 45 degrees |
| Parallelism | <= 10 arcsec |
| Perpendicularity | <= 5 arcmin |
| Flatness | lambda/10 at 632.8 nm |
| Surface quality | 10-5, MIL-O-13830A |
| AR coating reflectivity | <= 0.25% at 2940 nm |
| Damage threshold | >= 500 MW/cm2, 10 ns, 1 Hz at 1064 nm |
Typical physical and laser properties of Er:YAG crystal.
| Property | Typical Value |
|---|---|
| Crystal structure | Cubic |
| Lattice parameter | 12.01 A |
| Melting point | Approx. 1970 C |
| Mohs hardness | 8.5 |
| Density | 4.56 +/- 0.04 g/cm3 |
| Specific heat | Approx. 0.59 J/(g K), 0-20 C |
| Thermal expansion coefficient | [100] direction: 8.2 x 10-6/C, 0-250 C |
| Thermal conductivity | 14 W/(m K) at 20 C; 10.5 W/(m K) at 100 C |
| Laser transition | 4I11/2 to 4I13/2 |
| Laser wavelength | 2940 nm |
| Emission cross section | Approx. 3 x 10-20 cm2 |
| Index of refraction | Approx. 1.79 at 2940 nm |
Er:YAG vs. Related Laser Crystals
Er:YAG is selected when the laser design needs emission around 2940 nm and strong water absorption. Other laser crystals may be more suitable when the target wavelength, pump source, output power, pulse format, or Q-switching design is different.
| Crystal | Role | Key Wavelength / Range | Best Fit |
|---|---|---|---|
| Er:YAG | Gain medium | 2940 nm | Medical, dental, aesthetic, and water-absorption laser systems |
| Nd:YAG | Gain medium | 1064 nm class | Mature CW, pulsed, and Q-switched solid-state lasers |
| Yb:YAG | Gain medium | 1030 nm class | High-power diode-pumped and ultrafast laser systems |
| Nd:YVO4 | Gain medium | 1064 / 1342 / 914 nm class | Compact diode-pumped lasers requiring high absorption and gain |
| Cr:YAG | Passive Q-switch | About 950-1100 nm absorption range | Passive Q-switched Nd or Yb laser cavities |
| Ti:Sapphire | Tunable gain medium | About 660-1050 nm tuning range | Ultrafast and broadly tunable laser systems |
Design Notes for 2940 nm Er:YAG Lasers
For Er:YAG laser systems, the crystal specification should be matched to the pump design, cavity length, cooling method, output coupling, pulse format, and coating requirements. The 2940 nm wavelength is useful where water absorption is important, but final laser performance also depends on thermal loading, beam quality, resonator design, and system-level safety control.
Before production, confirm dopant concentration, orientation, rod or slab size, end-face flatness, surface quality, AR coating, damage threshold, and acceptance testing conditions. For OEM systems, drawings and cavity requirements are usually needed for accurate quotation.
How to Request an Er:YAG Crystal Quotation
Providing the following information helps reduce repeated communication and makes the quotation more accurate.
| RFQ Item | Information to Provide |
|---|---|
| Material requirement | Er:YAG dopant concentration, target wavelength, and application. |
| Geometry | Rod diameter and length, slab dimensions, chamfer, or complete drawing. |
| Orientation and tolerance | Crystal orientation, dimensional tolerance, parallelism, perpendicularity, and flatness. |
| Surface and coating | Surface quality, polishing, AR coating at 2940 nm, or custom coating requirement. |
| Laser design | Pump source, operating mode, pulse requirement, cavity design, cooling method, and expected output. |
| Order information | Prototype quantity, batch quantity, inspection criteria, delivery schedule, and packaging requirement. |
