Fused Silica Laser Lenses

Precision fused silica laser lenses designed for high-power laser beam focusing, collimation and beam shaping. Available in plano-convex, bi-convex, plano-concave and meniscus configurations with UV-grade AR coatings.

Key Specifications

Material	UV Fused Silica (SiO₂)
Transmission Range	185 – 2,500 nm
Lens Types	Plano-Convex, Bi-Convex, Plano-Concave, Meniscus
Diameter Range	3mm – 100mm
Focal Length Range	5mm – 2,000mm
Surface Quality	20-10 / 10-5 (MIL-PRF-13830B)
Surface Flatness	λ/4 @ 632.8nm (test plate)
Centration	< 3 arc min
Coating	AR @ 193/266/355/532/1064nm
LIDT	> 10 J/cm² @ 1064nm, 10ns

Material Options

Select the optimal optical material based on your wavelength, power, thermal environment and mechanical requirements.

UV Fused Silica — Standard for UV laser applications. Broad transmission, high LIDT, near-zero CTE.
N-BK7 — Economical for visible and NIR laser focusing. Suitable when UV transmission is not required.
CaF₂ — For deep UV (below 200nm) or when birefringence-free performance is critical at high energies.

Available Optical Materials

Select the optimal substrate material based on your wavelength, environment, and budget requirements.

Material	Transmission	Key Advantage	Considerations
UV Fused Silica	UV / VIS / NIR (185-2100nm)	Excellent UV transmission, high laser damage threshold	Higher cost than BK7
N-BK7	VIS / NIR (350-2000nm)	General-purpose, low cost, good homogeneity	Not suitable for UV < 350nm
CaF₂ (Calcium Fluoride)	Deep UV / VIS / IR (130-7800nm)	Broadest transmission range, low refractive index	Fragile, hygroscopic, higher cost
Sapphire	UV / VIS / NIR (150-5500nm)	Extremely hard (9H), scratch resistant	Birefringent, higher refractive index

Not sure which material to choose?

Ask AI Optical Engineer

Coating Options

Coatings are engineered around your specific wavelength and operating conditions.

AR @ 355nm — R < 0.1% per surface. For Nd:YAG 3rd harmonic focusing.
AR @ 532nm — R < 0.1% per surface. For Nd:YAG/Green laser systems.
AR @ 1064nm — R < 0.1% per surface. For Nd:YAG fundamental.
BBAR UV-NIR — R < 0.5% across 350–1100nm. Multi-wavelength systems.
V-line AR — Optimized for specific laser line. Lowest residual reflectance at design wavelength.

Manufacturing Tolerances

We optimize specifications to match your system requirements — not over-specify. Tighter tolerances increase cost without always improving system performance. Our engineers will work with you to identify which parameters actually matter for your application and where standard tolerances are sufficient. Typical manufacturing capabilities:

Surface quality: from 60-40 to 10-5 scratch-dig
Surface flatness: from λ/4 to λ/20 per inch
Dimensional tolerance: ±0.01mm to ±0.05mm
Centration: <3 arc min standard, <30 arc sec precision

Inspection & Quality

Every component undergoes 100% inspection before shipment. We provide full inspection documentation including interferometer reports, spectral transmission curves, surface quality images and dimensional measurement data. Equipment capabilities:

Laser interferometry: λ/100 resolution for flatness and wavefront
Spectrophotometry: 190nm – 25μm transmission and reflection
Surface inspection: MIL-PRF-13830B compliant
Dimensional metrology: ±0.01mm accuracy

Applications

Laser beam focusing and spot size control
Nd:YAG and fiber laser beam delivery
UV laser marking and micromachining optics
Laser cutting head focusing optics
Laser diode collimation
Scientific instrumentation and research lasers

Engineering Considerations

Focal length tolerance: Standard tolerance is ±1%. For precision applications requiring ±0.5% or tighter, specify during ordering. Tighter focal length tolerance requires additional measurement and selection, increasing cost.

Thermal lensing: At high average powers (>50W CW), even fused silica can develop thermal lens effects due to dn/dT (11 × 10⁻⁶/K). For high-power systems, consider the thermal focal shift in your beam delivery design.

Surface quality for high power: 20-10 scratch-dig is standard for most laser focusing. For intracavity or very high peak power applications, specify 10-5 to minimize scatter-induced damage sites.

Is Fused Silica the Right Lens Material for Your Laser System?

Fused silica is the standard for UV and high-power laser lenses. Use this guide to verify it matches your system requirements.

Wavelength

Your Requirement	Best Material	Why
UV laser (< 350nm)	Fused Silica ✓	Fused silica is the standard for UV laser optics. Transmits from 185nm with excellent purity.
Visible-NIR (350-2000nm)	Nbk7	For visible-NIR lasers, N-BK7 is more economical. Fused silica is overkill unless high power demands it.
IR beyond 2.5um	Znse	Fused silica is opaque beyond 2.5um. Use ZnSe for CO2 laser, Ge for thermal IR.

Laser Power

Your Requirement	Best Material	Why
High-power (> 100W CW)	Fused Silica ✓	Low thermal expansion and high LIDT make fused silica essential for high-power laser focusing.
Low-power (< 50W)	Nbk7	For low-power visible-NIR lasers, N-BK7 provides adequate performance at lower cost.

Pulse Regime

Your Requirement	Best Material	Why
Ultrafast (< 100fs)	Caf2	For femtosecond lasers, CaF2 offers lower group velocity dispersion to minimize pulse broadening.
Nanosecond or longer / CW	Fused Silica ✓	For ns-pulsed or CW lasers, fused silica provides excellent performance.

Summary

Fused silica is the right choice for UV lasers, high-power laser focusing, and applications requiring low thermal expansion. For visible-NIR low-power systems, N-BK7 is more economical. For ultrafast lasers, consider CaF2.

Engineering Documentation

The following documentation is available upon request for qualified engineering projects:

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Dimensional Drawing

CAD & dimensional specs per your requirements

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Material Data Sheet

Material properties, transmission curves & certificates

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Coating Performance Curve

Spectrophotometric measurement data

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Inspection Report

Surface quality, flatness, centration & dimensional data

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Certificate of Conformance

CoC with full traceability per project requirements

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Custom Specification Sheet

Application-specific specification documentation

Documentation availability depends on project scope and order quantity. Request details during RFQ.

Frequently Asked Questions

How do I choose between plano-convex and bi-convex for laser focusing?

For focusing a collimated beam to a point, use plano-convex with the curved surface facing the longer conjugate distance. For 1:1 imaging or when conjugate distances are equal, bi-convex provides slightly better performance. Plano-convex is more commonly used and generally less expensive.

What focal length tolerance do I need?

Most laser focusing applications work with ±1% focal length tolerance. Precision applications like lithography or metrology may require ±0.5% or ±0.2%. Tighter tolerance increases cost due to additional measurement and selection.

Can fused silica lenses handle high-power CW lasers?

Yes, fused silica handles high average power well due to low absorption and high thermal conductivity. For CW power above 50W, account for thermal lensing in your system design. We can provide thermal modeling guidance for your specific application.