NIR Antireflection Coated N-BK7 Bi-Concave Lenses
NIR Antireflection Coated N-BK7 Bi-Concave Lenses
Our 650-1000 nm antireflection coated N-BK7 precision bi-concave (double-concave) lenses are polished to tight tolerances using master test plates to ensure minimum wavefront distortion for demanding laser collimating applications.
- 650-1000 nm anti-reflection coating
- High performance 40-20 scratch-dig N-BK7 substrates
- Double-Concave shape for beam expansion applications
- Standardized focal lengths across different lens sizes See All Features
| Compare | Description | Drawings, CAD & Specs | Avail. | Price | ||
|---|---|---|---|---|---|---|
 | KBC010AR.16Bi-Concave Lens, N-BK7, 6.35 mm Diameter, -12.5 mm EFL, 650-1000nm | In Stock | ||||
| KBC013AR.16Bi-Concave Lens, N-BK7, 6.35 mm Diameter, -6.3 mm EFL, 650-1000nm | In Stock FREE 2-day shipping on thousands of products on Newport.com Learn More | ||||
 | KBC016AR.16Bi-Concave Lens, N-BK7, 12.7 mm Diameter, -100 mm EFL, 650-1000nm | In Stock | ||||
| KBC019AR.16Bi-Concave Lens, N-BK7, 12.7 mm Diameter, -75 mm EFL, 650-1000nm | In Stock | ||||
| KBC022AR.16Bi-Concave Lens, N-BK7, 12.7 mm Diameter, -50 mm EFL, 650-1000nm | In Stock | ||||
| KBC025AR.16Bi-Concave Lens, N-BK7, 12.7 mm Diameter, -25 mm EFL, 650-1000nm | In Stock FREE 2-day shipping on thousands of products on Newport.com Learn More | ||||
| KBC028AR.16Bi-Concave Lens, N-BK7, 12.7 mm Diameter, -12.5 mm EFL, 650-1000nm | In Stock FREE 2-day shipping on thousands of products on Newport.com Learn More | ||||
 | KBC031AR.16Bi-Concave Lens, N-BK7, 25.4 mm Diameter, -200 mm EFL, 650-1000nm | In Stock | ||||
| KBC034AR.16Bi-Concave Lens, N-BK7, 25.4 mm Diameter, -150 mm EFL, 650-1000nm | In Stock | ||||
| KBC037AR.16Bi-Concave Lens, N-BK7, 25.4 mm Diameter, -100 mm EFL, 650-1000nm | In Stock |
Mounting Options
We offer a full range of optical lens mounts to meet various experimental requirements. Below lists the recommended mounts for spherical lenses of standard sizes. Please see our Lens Mount Guide for additional information.
Note: besides the diameter, please check the Edge Thickness (Te) specification of the lens and the lens mount to ensure compatibility before purchasing.
| Lens Diameter |  A-Line™ Lens Mounts |
 LT Series Lens Tubes |
 LP Series Lens Positioners |
 Optics Cage Plus Series |
|---|---|---|---|---|
| 76.2 mm | ( |
N/A | N/A | N/A |
| 50.8 mm | ( |
N/A | ||
| 38.1 mm | ( |
LT20 lens tube with |
LP-2 lens positioner with |
N/A |
| 25.4 mm | ( |
|||
| 12.7 mm | ( |
N/A | ||
| 6.35 mm | LT05 lens tube with |
LP-05 lens positioner with |
N/A |
For non-standard sizes not listed above, check out our variable size lens mounts.
Specifications
- Lens ShapeBi-Concave (Double-Concave)
- Lens MaterialN-BK7
- Antireflection Coating650-1000 nm
- Coating TypeNIR Multilayer
- Coating CodeAR.16
- Damage Threshold7.5 J/cm2, 10 ns pulses, 10 Hz at 1064 nm
- Surface Quality40-20 scratch-dig
- Centration≤3 arc min
- Chamfers0–0.8 mm face width
- Chamfers Angle/Tolerance45° ±15°, typical
- Focal Length Tolerance±1 %
- Diameter Tolerance+0/-0.1 mm
- Center Thickness Tolerance±0.1 mm
- Clear Aperture≥central 90% of diameter
- Cleaning
Features
N-BK7 Substrates for VIS and NIR Applications
N-BK7 is an excellent lens material for most visible and near infrared applications. It is the most common borosilicate crown optical glass, and it provides great performance at a good value. Its high homogeneity, low bubble and inclusion content, and straightforward manufacturability make it a good choice for transmissive optics. N-BK7 is also relatively hard and shows good scratch resistance. The transmission range for BK 7 is 380 to 2100 nm. It is not recommended for temperature sensitive applications, such as precision mirrors. For more information, refer to our optical materials technical note.
Precision Bi-Concave Lens Surfaces
Our precision N-BK7 bi-concave lenses are polished to tight tolerances minimizing wavefront distortion. Tight surface quality tolerances minimize scatter and unwanted diffraction effects. These lenses have a 40-20 scratch-dig surface quality, and a λ/4 surface irregularity. For more information, refer to the optical surfaces technical note.
Broadband Multilayer NIR Antireflection Coatings
Our broadband AR.16 antireflection coating improves the transmission efficiency of these lenses by reducing surface reflections over a 650-1000 nm wavelength range. The NIR AR multi-layer coating improves the performance over uncoated surfaces. It features a damage threshold of 7.5 J/cm2 for 10 ns pulses at 10 Hz and 1064 nm.
Standardized Bi-Concave Focal Lengths
Standard double concave effective focal lengths provide a systematic approach allowing for lenses of different sizes and materials to be interchanged without requiring other changes to your optical system.
Bi-Concave Lens Shape for Beam Expansion
Bi-Concave lenses are the best choice where object and image are at absolute conjugate ratios closer to 1:1 with converging input beam. The output rays appear to be diverging from a virtual image located on the object side of the lens. The distance from this virtual point to the lens is known as the focal length. Similar to the Plano-Concave lenses, the Bi-concave lenses have negative focal lengths, thereby causing collimated incident light to diverge. Bi-Concave lenses have equal radius of curvature on both side of the lens. They are generally used to expand light or increase focal length in existing systems, such as beam expanders and projection systems.
