What Scientists Must Prepare Before Ordering Custom Crystals

What Scientists Must Prepare Before Ordering Custom Crystals

Ordering custom-grown crystals is not the same as buying off-the-shelf materials.
Research-grade single crystals require precise specifications for:

  • Growth method
  • Orientation
  • Dopant concentration
  • Purity
  • Geometry
  • Surface finish
  • Optical quality
  • Mechanical tolerances

This page provides a researcher-ready checklist, ensuring accurate manufacturing, minimal rework, and the best crystal performance for your experiment.

SECTION A — 1. Choose the Crystal Material & Growth Method

Scientists must specify:

✔ Crystal Type

Examples you supply:

  • Scintillators: LYSO, YSO, BGO, CsI:Tl, NaI:Tl, GAGG:Ce
  • Laser crystals: YAG, Nd:YAG, Er:YAG, Ti:Sapphire
  • Optical crystals: Sapphire, Quartz, CaF₂, MgF₂
  • Semiconductors: Ga₂O₃, ZnO, CdZnTe
  • Functional materials: LiNbO₃, LiTaO₃

✔ Growth Method

If known, specify:

  • Czochralski (CZ)
  • Bridgman / VGF
  • Hydrothermal
  • Flux growth
  • Floating-zone

SECTION B — 2. Size & Geometry (DIMENSIONS)

This is mandatory for every order.

✔ Specify:

  • Length × width × thickness
  • Diameter (for round wafers or rods)
  • Rod size vs plate size
  • Whether cutting is required
  • Edge bevel or chamfer

SECTION C — 3. Orientation (MOST IMPORTANT for optics/laser/scintillators)

✔ Specify crystallographic orientation:

Common options:

  • (100), (110), (111)
  • c-plane, a-plane, r-plane (sapphire)
  • X-cut, Y-cut, Z-cut（quartz / LiNbO₃）

✔ Orientation tolerance:

Typical vendor capabilities:

  • ±0.5° (standard)
  • ±0.2° (precision)
  • ±0.1° (high-end optical/laser grade)

If not specified → default ±0.5°.

SECTION D — 4. Doping Level & Uniformity

✔ Mandatory for doped crystals:

  • Dopant element (Ce, Nd, Pr, Ti, MgO…)
  • Concentration (mol%, wt%, ppm)
  • Uniformity requirement
  • Axial/radial gradient limit (if required)

Examples:

  • Nd:YAG (1.0 at.% Nd)
  • Ce:GAGG (0.5–1 mol%)
  • Ti:Sapphire (0.15–0.25 wt%)

SECTION E — 5. Purity Requirements (RAW MATERIAL SPEC)

Typical research grades:

  • 4N = 99.99%
  • 5N = 99.999%
  • 6N = 99.9999%（semiconductor / scintillator）

You should specify if you need:

  • Low α-radiation raw materials
  • Low Fe contamination
  • UV-grade or laser-grade purity

SECTION F — 6. Surface Finish (POLISHING & COATING)

✔ Polishing options:

  • Fine-ground (not optical)
  • Optical polish, single-side
  • Optical polish, double-side
  • Scratch–dig: 80-50 / 60-40 / 40-20 / 20-10

✔ Surface flatness:

  • λ/2
  • λ/4
  • λ/10 for laser cavity mirrors

✔ Optional coatings:

  • AR coating (532 nm / 1064 nm / broadband VIS)
  • HR mirror coating
  • Protective coating for scintillators

SECTION G — 7. Important Mechanical Spec

 

✔ Dimensional Tolerances

Parameter Typical Tolerance High Precision
Length / width ±0.05–0.10 mm ±0.02 mm
Thickness ±0.05 mm ±0.01–0.02 mm
Diameter (wafers) ±0.05 mm ±0.02 mm
Parallelism <10–20 µm <5 µm
Perpendicularity <0.1 mm <0.03 mm

If not specified → supplier uses ±0.1 mm default.

✔ Orientation Tolerance

  • Standard: ±0.5°
  • Laser/scintillator: ±0.2°
  • High-end optical: ±0.1° or better

✔ Surface Quality Tolerance

Scratch–dig:

  • Standard optics: 60-40
  • Scientific optics: 40-20
  • High-end laser: 20-10

Surface roughness:

  • Ra < 5 nm (optical)
  • Ra < 20 nm (general polished)

✔ Flatness Tolerance

  • λ/2 → general optical
  • λ/4 → research optics
  • λ/10 → laser resonator grade

✔ Edge Tolerance

Specify:

  • Chamfer size (0.1–0.3 mm)
  • Radius
  • Safety bevel (for brittle crystals)


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