N-SF11 Plano-Concave Lenses, AR Coated for 350

Overview
Graphs
Mounting Options
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Common Specifications
Lens Shape	Plano / Concave
Substrate Material	N-SF11^a
AR Coating Range^b	350 - 700 nm
Diameters Available	6 mm, 9 mm, 1/2", or 1"
Diameter Tolerance	+0.00/-0.10 mm
Thickness Tolerance	±0.1 mm
Focal Length Tolerance	±1%
Design Wavelength	587.6 nm
Index of Refraction @ 633 nm	1.778
Abbe Number	v_d = 25.76
Surface Quality	40-20 Scratch-Dig
Surface Flatness (Plano Side)	λ/2
Spherical Surface Power (Concave Side)^c	3λ/2
Surface Irregularity (Peak to Valley)	λ/4
Centration	≤3 arcmin
Clear Aperture	>90% of Diameter
Focal Length Tolerance	±1%

Click Link for Detailed Specifications on the Substrate
The average reflectivity over the AR coating range is <0.5%. These lenses are also available uncoated, or with an AR coating for the 650 - 1050 nm range or the 1050 - 1700 nm range.
Much like surface flatness for flat optics, spherical surface power is a measure of the deviation between the surface of the curved optic and a calibrated reference gauge, typically for a 633 nm source, unless otherwise stated. This specification is also commonly referred to as surface fit.

Zemax Files
Click on the red Document icon next to the item numbers below to access the Zemax file download. Our entire Zemax Catalog is also available.

Features

Material: N-SF11
Broadband Antireflection Coating for the 350 - 700 nm Range
Choose from 4 Diameters: 6 mm, 9 mm, 1/2", or 1"
Offers Better Chemical Resistance than N-BK7

These Plano-Concave lenses, which are fabricated from N-SF11 glass, have a broadband antireflection coating for the 350 - 700 nm range deposited on both faces. The AR coating greatly reduces the 4% losses per surface incurred when using an uncoated lens (see the Graphs tab for details).

N-SF11 glass, a RoHS compliant version of SF11, is most commonly used in harsh environments since it is inert to biological degradation and resistant to naturally encountered chemicals, alkalis, and acids. With an uncoated wavelength range of 420 nm - 2.3 μm, N-SF11 also offers a usage range that is slightly shifted to the red compared to N-BK7, which is our RoHS-compliant BK7 glass and has an uncoated wavelength range of 350 nm - 2.0 μm. Since N-SF11 glass has a lower Abbe Number than N-BK7 glass (25.76 compared to 64.17), it is associated with more dispersion.

Like all plano-concave lenses, these lenses have negative focal lengths and can be used to diverge collimated beams. In this case, the curved surface of the lens should face the source to minimize spherical aberration. In addition, they can be employed to offset the effects of spherical aberration caused by other lenses in an optical system.

Plano-Concave Lens Selection Guide
N-BK7	Uncoated -A (350 - 700 nm) -B (650 - 1050 nm) -C (1050 - 1700 nm)
N-SF11	Uncoated -A (350 - 700 nm) -B (650 - 1050 nm) -C (1050 - 1700 nm)
UV Fused Silica	Uncoated -UV (245 - 400 nm) -A (350 - 700 nm) -B (650 - 1050 nm) -C (1050 - 1700 nm)
CaF₂	Uncoated -E (3 - 5 µm)
ZnSe	-F (8 - 12 µm)

Custom Coatings are also available. Please contact technical support for a quote.

Quick Links to Other Spherical Singlets
Plano-Convex	Bi-Convex	Best Form	Plano-Concave	Bi-Concave	Positive Meniscus	Negative Meniscus

Below is the measured transmission for a 10 mm thick uncoated sample of N-SF11 using normal incident light. Each lens can be purchased uncoated or with our -A (350-700 nm), -B (650 - 1050 nm), or -C (1050 - 1700 nm) antireflection coating.

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Click Here for Raw Data

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Click Here for Raw Data
The blue shaded region indicates the specified 350 - 700 nm wavelength range for optimum performance.

Thorlabs' Standard Broadband Antireflection Coatings

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CXY1 Translation Mount and
SM1 Lens Tube Mounted in a
30 mm Cage System

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Ø1" Optic Mounted in a
ST1XY-S XY Translator

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LMR1 Fixed Mount with Ø1" Lens

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LM2XY Translating Mount with Ø2" Lens

Recommended Mounting Options for Thorlabs Lenses
Item #		Mounts for Ø2 mm to Ø10 mm Optics
Imperial	Metric	Mounts for Ø2 mm to Ø10 mm Optics
(Various)		Fixed Lens Mounts and Mini-Series Fixed Lens Mounts for Small Optics, Ø5 mm to Ø10 mm
(Various)		Small Optic Adapters for Use with Standard Fixed Lens Mounts, Ø2 mm to Ø10 mm
Item #		Mounts for Ø1/2" (Ø12.7 mm) Optics
Imperial	Metric	Mounts for Ø1/2" (Ø12.7 mm) Optics
LMR05	LMR05/M	Fixed Lens Mount for Ø1/2" Optics
MLH05	MLH05/M	Mini-Series Fixed Lens Mount for Ø1/2" Optics
LM05XY	LM05XY/M	Translating Lens Mount for Ø1/2" Optics
SCP05		16 mm Cage System, XY Translation Mount for Ø1/2" Optics
(Various)		Ø1/2" Lens Tubes, Optional SM05RRC Retaining Ring for High-Curvature Lenses (See Below)
Item #		Mounts for Ø1" (Ø25.4 mm) Optics
Imperial	Metric	Mounts for Ø1" (Ø25.4 mm) Optics
LMR1	LMR1/M	Fixed Lens Mount for Ø1" Optics
LM1XY	LM1XY/M	Translating Lens Mount for Ø1" Optics
ST1XY-S	ST1XY-S/M	Translating Lens Mount with Micrometer Drives (Other Drives Available)
CXY1		30 mm Cage System, XY Translation Mount for Ø1" Optics
(Various)		Ø1" Lens Tubes, Optional SM1RRC Retaining Ring for High-Curvature Lenses (See Below)
Item #		Mount for Ø1.5" Optics
Imperial	Metric	Mount for Ø1.5" Optics
LMR1.5	LMR1.5/M	Fixed Lens Mount for Ø1.5" Optics
(Various)		Ø1.5" Lens Tubes, Optional SM1.5RR Retaining Ring for Ø1.5" Lens Tubes and Mounts
Item #		Mounts for Ø2" (Ø50.8 mm) Optics
Imperial	Metric	Mounts for Ø2" (Ø50.8 mm) Optics
LMR2	LMR2/M	Fixed Lens Mount for Ø2" Optics
LM2XY	LM2XY/M	Translating Lens Mount for Ø2" Optics
CXY2		60 mm Cage System, XY Translation Mount for Ø2" Optics
(Various)		Ø2" Lens Tubes, Optional SM2RRC Retaining Ring for High-Curvature Lenses (See Below)
Item #		Adjustable Optic Mounts
Imperial	Metric	Adjustable Optic Mounts
LH1	LH1/M	Adjustable Mount for Ø0.28" (Ø7.1 mm) to Ø1.80" (Ø45.7 mm) Optics
LH2	LH2/M	Adjustable Mount for Ø0.77" (Ø19.6 mm) to Ø2.28" (Ø57.9 mm) Optics
VG100	VG100/M	Adjustable Clamp for Ø0.5" (Ø13 mm) to Ø3.5" (Ø89 mm) Optics
SCL03	SCL03/M	Self-Centering Mount for Ø0.15" (Ø3.8 mm) to Ø1.77" (Ø45.0 mm) Optics
SCL04	SCL04/M	Self-Centering Mount for Ø0.15" (Ø3.8 mm) to Ø3.00" (Ø76.2 mm) Optics
LH160C	LH160C/M	Adjustable Mount for 60 mm Cage Systems, Ø0.50" (Ø13 mm) to Ø2.00" (Ø50.8 mm) Optics
SCL60C	SCL60C/M	Self-Centering Mount for 60 mm Cage Systems, Ø0.15" (Ø3.8 mm) to Ø1.77" (Ø45.0 mm) Optics

Mounting High-Curvature Optics

Thorlabs' retaining rings are used to secure unmounted optics within lens tubes or optic mounts. These rings are secured in position using a compatible spanner wrench. For flat or low-curvature optics, standard retaining rings manufactured from anodized aluminum are available from Ø5 mm to Ø4". For high-curvature optics, extra-thick retaining rings are available in Ø1/2", Ø1", and Ø2" sizes.

Extra-thick retaining rings offer several features that aid in mounting high-curvature optics such as aspheric lenses, short-focal-length plano-convex lenses, and condenser lenses. As shown in the animation to the right, the guide flange of the spanner wrench will collide with the surface of high-curvature lenses when using a standard retaining ring, potentially scratching the optic. This contact also creates a gap between the spanner wrench and retaining ring, preventing the ring from tightening correctly. Extra-thick retaining rings provide the necessary clearance for the spanner wrench to secure the lens without coming into contact with the optic surface.