Our N-BK7 precision bi-concave lenses are polished to tight tolerances using master test plates to ensure minimum wavefront distortion for demanding laser collimating applications.
Low cost, high performance N-BK7 optical glass
Bi-Concave shape for beam expansion applications
≤ λ/4 surface irregularity, 40-20 scratch-dig
Broadband or laser line AR coatings available
Standardized focal lengths across different lens sizes
RoHS Certified
Features
N-BK7 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.
High Quality Precision Lens Surfaces
Our precision bi-convex 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.
Broadband Visible Antireflection Coatings
Our AR.14 broadband multilayer antireflection coating markedly improves the transmission efficiency of these lenses by reducing surface reflections over a 430-700 nm wavelength range. This AR coating performs effectively for multiple visible wavelengths and tunable lasers eliminating the need for several sets of optics.
Broadband Multilayer IR Antireflection Coatings
We offer two multilayer AR coatings options for IR and NIR applications. Our AR.16 coating is recommended for NIR applications in the 650-1000 nm range. Our AR.18 coating is for IR applications in the 1000-1550 nm range.
1064 nm Laser Line Antireflection V-Coating
Our AR.33 laser line V-coating offers the lowest reflectance at 1064 nm for maximum transmission while maintaining high durability and high damage resistance. Valuable laser energy is efficiently transmitted through the plano-convex lens rather than lost to surface reflection and scattering. The trade off to its superior performance is the minimal laser line wavelength range.
Standardized Focal Lengths
Standard effective focal lengths provide a systematic approach allowing for lenses of different sizes to be interchanged without requiring other changes to your optical system.
RoHS Compliant
These lenses have been tested for dangerous substances like Pb, Cd, Hg, Hex-Cr, PBB, and PBDE and have been found to be in compliance with RoHS allowable levels.
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.
Our N-BK7 precision bi-concave lenses are polished to tight tolerances using master test plates to ensure minimum wavefront distortion for demanding laser collimating applications.
- Low cost, high performance N-BK7 optical glass
- Bi-Concave shape for beam expansion applications
- ≤ λ/4 surface irregularity, 40-20 scratch-dig
- Broadband or laser line AR coatings available
- Standardized focal lengths across different lens sizes
- RoHS Certified
Features
N-BK7 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.
High Quality Precision Lens Surfaces
Our precision bi-convex 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.
Broadband Visible Antireflection Coatings
Our AR.14 broadband multilayer antireflection coating markedly improves the transmission efficiency of these lenses by reducing surface reflections over a 430-700 nm wavelength range. This AR coating performs effectively for multiple visible wavelengths and tunable lasers eliminating the need for several sets of optics.
Broadband Multilayer IR Antireflection Coatings
We offer two multilayer AR coatings options for IR and NIR applications. Our AR.16 coating is recommended for NIR applications in the 650-1000 nm range. Our AR.18 coating is for IR applications in the 1000-1550 nm range.
1064 nm Laser Line Antireflection V-Coating
Our AR.33 laser line V-coating offers the lowest reflectance at 1064 nm for maximum transmission while maintaining high durability and high damage resistance. Valuable laser energy is efficiently transmitted through the plano-convex lens rather than lost to surface reflection and scattering. The trade off to its superior performance is the minimal laser line wavelength range.
Standardized Focal Lengths
Standard effective focal lengths provide a systematic approach allowing for lenses of different sizes to be interchanged without requiring other changes to your optical system.
RoHS Compliant
These lenses have been tested for dangerous substances like Pb, Cd, Hg, Hex-Cr, PBB, and PBDE and have been found to be in compliance with RoHS allowable levels.
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.
