Custom Optical Components (Quartz, Sapphire, Windows, Viewports) — Selection Guide

Custom Optical Components for Research Labs — Quartz, Sapphire, Windows & Viewports

Optical components are essential in:

  • Vacuum chambers
  • Spectroscopy & photonics
  • Furnaces & high-temperature reactors
  • Plasma diagnostics
  • Laser systems
  • Thin-film monitoring
  • Imaging setups
  • LIBS / Raman systems
  • Optical access for reactors or scientific instruments

Quartz and sapphire are the two most widely used optical materials because they combine optical clarity with extreme thermal and mechanical stability.

This guide explains how to select the correct optical window based on temperature, wavelength, vacuum compatibility, and chemical exposure.

SECTION A — Quartz vs Sapphire Windows (Quick Comparison)

Property Quartz (Fused Silica) Sapphire (Single Crystal Al₂O₃)
Max Temperature ~1100–1200°C 1800–2000°C
Optical Transmission 190 nm – 2.5 µm 150 nm – 5 µm
Strength Moderate Very high
Hardness 7 Mohs 9 Mohs
Thermal Shock Resistance Good Excellent
Plasma Resistance Good Excellent
Chemical Resistance High Very high
Cost Low Higher

Summary:
✔ Quartz = optical, low/medium temperature, low cost
✔ Sapphire = extreme temperature, pressure, plasma, scratch-resistant, strongest optical material

SECTION B — Optical Transmission Ranges

Quartz (Fused Silica)

  • UV → Visible → NIR (190 nm – 2500 nm)
  • Very low autofluorescence
  • Good for UV lasers, imaging, spectroscopy

Sapphire

  • Deep UV → Visible → Mid-IR (150 nm – 5000 nm)
  • Extremely durable
  • Ideal for harsh environments
  • Great for high-power lasers

When optical clarity + strength are both required → choose sapphire.

SECTION C — Temperature & Vacuum Compatibility

Material Max Temp Vacuum Rating Notes
Quartz 1100–1200°C Excellent Devitrifies above 1150°C
Sapphire 1800–2000°C Excellent Best for furnace & plasma
Glass ~300°C Good Low cost, not for extreme heat
ZnSe ~250°C Good For IR lasers, soft material

Sapphire: best for

  • Furnace windows
  • Plasma chambers
  • High-temperature reactors
  • Laser ports with high energy density

SECTION D — Surface Flatness, Polishing & Scratch-Dig

✔ Polishing Grades

  • Standard polish
  • 1-side or 2-side optical polish
  • λ/4 or λ/10 flatness for precision lasers

✔ Scratch-Dig (Mil-PRF standard)

  • 80-50 → industrial
  • 60-40 → standard optics
  • 40-20 → scientific optics
  • 20-10 → high-end laser optics

✔ Chamfering

Prevents edge chipping and is recommended for all sapphire windows.

✔ Parallelism

Important for interferometry & high-precision spectroscopy.

SECTION E — Coatings for Optical Windows

✔ AR (Anti-Reflection) Coating

  • 1064 nm
  • 532 nm
  • Broadband VIS
  • UV optimized

✔ HR (High-Reflection)

  • For laser mirrors

✔ DLC (Diamond-Like Carbon)

  • Scratch-resistant
  • Best for sapphire under harsh conditions

✔ ITO Coating

  • Transparent conductive layer

✔ Metal coatings

  • Au, Al, Cr for optical filters

SECTION F — Machining Capabilities for Quartz & Sapphire

✔ Shaping

  • Circular
  • Rectangular
  • Elliptical
  • Custom geometry

✔ Drilling (Sapphire drilling available)

  • Holes
  • Slots
  • Countersinks
  • Through-holes

✔ Edge shaping

  • Bevel
  • Chamfer
  • Radius

✔ Thickness options

  • 0.2 mm – 10 mm (quartz)
  • 0.3 mm – 6 mm (sapphire)

✔ Diameter options

  • 5 mm – 150 mm

✔ Custom polishing

  • Single-side
  • Double-side
  • Optical-grade

SECTION G — What Customers Should Provide Before Ordering

✔ 1. Material

Quartz / Sapphire / Glass / ZnSe / MgF₂

✔ 2. Geometry

  • Diameter / Width / Height
  • Thickness
  • Tolerance required

✔ 3. Surface finish

  • Polished?
  • Optical grade?
  • Scratch-dig?

✔ 4. Coatings

  • AR coating?
  • HR coating?
  • Clear window vs filtering window?

✔ 5. Environment

  • Temperature
  • Vacuum level
  • Plasma exposure
  • Mechanical stress

✔ 6. Application purpose

(affects material choice and flatness)



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