40-20 Scratch / Dig Achromats
Last Updated: April 1, 2025
Description
40-20 Scratch / Dig Achromats are optical components characterized by their surface quality, specifically the allowable size of surface defects. The "40-20" designation indicates that the average diameter of digs is 0.20 mm and the average length of scratches is 0.40 mm. These achromats are designed to minimize chromatic aberration by combining two or more types of optical glass with different dispersion properties.
Working Principle
Achromatic lenses work by using a combination of lens elements made from different types of glass with varying dispersion properties. Typically, a concave lens element with high dispersion is paired with a convex lens element with low dispersion. This configuration allows the lenses to counteract each other's distortions, effectively reducing chromatic aberration. The 40-20 scratch/dig rating ensures a certain level of surface quality, which is crucial for maintaining the optical performance of the achromat.
Applications
40-20 Scratch / Dig Achromats are used in various optical systems where moderate surface quality is acceptable. They are suitable for applications such as imaging systems where high precision is not the primary concern. Specific examples include use in certain types of cameras, microscopes, and telescopes where the cost of higher quality lenses is not justified.
Advantages over other Achromats
Compared to achromats with higher scratch/dig ratings like 60-40 or 80-50, 40-20 Scratch / Dig Achromats offer improved surface quality, which can lead to better optical performance in terms of reducing unwanted reflections and scattering. They are also more cost-effective than higher precision achromats like 20-10 or 10-5, making them a good choice for applications where budget constraints are a consideration.
Limitations
One limitation of 40-20 Scratch / Dig Achromats is that they may not be suitable for high-precision applications, such as high-power laser systems, which require higher surface quality to prevent scattering and absorption of light. Additionally, the manufacturing cost increases as the scratch/dig rating improves, so these achromats may not be the best choice for applications requiring the highest optical performance.
Considerations
When selecting 40-20 Scratch / Dig Achromats, it is important to consider the initial cost, which is generally lower than that of achromats with higher surface quality ratings. However, the trade-off is in the optical performance, which may not meet the requirements of all applications. Operating expenses are typically low, but durability and maintenance costs can vary depending on the specific application and environmental conditions. It is also crucial to consider the full spectral range of the system to ensure compatibility with the achromat's performance characteristics.
from Newport MKS
The PAC019 Visible Achromatic Doublet Lens is a 400 to 700 nm antireflection coated, 1/2 inch (12.7 mm) diameter, N-BaF10 and N-SF14 precision achromatic doublet lens with an effective focal length of 19.0 mm. This achromat is computer designed to effectively minimize spherical aberration and coma... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Focal Length: 15.1
- Achromat Type: Doublet
- Center Thickness: 6.85
from Suzhou Jiujon Optics Co., Ltd
Achromatic lenses are types of lenses that are designed to minimize chromatic aberration, which is a common optical problem that causes colors to appear differently when passing through a lens. These lenses use a combination of two or more optical materials with different refractive indices to focus... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Lens Features: Antireflection Coating
from Newport MKS
The PAC052 Visible Achromatic Doublet Lens is a 400 to 700 nm antireflection coated, 1 inch (25.4 mm) diameter, N-BK7 and N-SF5 precision achromatic doublet lens with an effective focal length of 100 mm. This achromat is computer designed to effectively minimize spherical aberration and coma when... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Focal Length: 96.5
- Achromat Type: Doublet
- Center Thickness: 7.17
from Newport MKS
The PAC073 Visible Achromatic Doublet Lens is a 400 to 700 nm antireflection coated, 1.5 inch (38.1 mm) diameter, N-BaF10 and N-SF10 precision achromatic doublet lens with an effective focal length of 100 mm. This achromat is computer designed to effectively minimize spherical aberration and coma... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Focal Length: 92.9
- Achromat Type: Doublet
- Center Thickness: 12.4
from Newport MKS
The PAC086 Visible Achromatic Doublet Lens is a 400 to 700 nm antireflection coated, 2 inch (50.8 mm) diameter, N-BK7 and N-SF5 precision achromatic doublet lens with an effective focal length of 150 mm. This achromat is computer designed to effectively minimize spherical aberration and coma when... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Focal Length: 144
- Achromat Type: Doublet
- Center Thickness: 12.5
from Newport MKS
The PAC010 Visible Achromatic Doublet Lens is a 400 to 700 nm antireflection coated, 1/4 inch (6.35 mm) diameter, N-BaF10 and N-SF10 precision achromatic doublet lens with an effective focal length of 12.7 mm. This achromat is computer designed to effectively minimize spherical aberration and coma... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Focal Length: 10.7
- Achromat Type: Doublet
- Center Thickness: 3.4
from Newport MKS
The PAC10AR.15 Broadband Achromatic Lens is a 345 nm to 700 nm anti-reflection coated, 0.49 inch (12.5 mm) diameter, N-FK5 and N-F2 achromatic doublet lens with an effective focal length of 25.0 mm. This achromat is computer optimized to provide diffraction limited performance for polychromatic... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Focal Length: 21.69
- Achromat Type: Doublet
- Center Thickness: 7
from Newport MKS
The PAC18AR.15 Broadband Achromatic Lens is a 345 nm to 700 nm anti-reflection coated, 0.98 inch (25.0 mm) diameter, N-FK5 and N-F2 achromatic doublet lens with an effective focal length of 100.0 mm. This achromat is computer optimized to provide diffraction limited performance for polychromatic... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Focal Length: 96.68
- Achromat Type: Doublet
- Center Thickness: 7.5
from Newport MKS
The PAC01AR.16 Near IR Achromatic Lens is a 750 to 1550 nm antireflection coated, 0.47 inch (12.0 mm) diameter, N-LaK22 and N-SF6 achromatic doublet lens with an effective focal length of 18.0 mm. This achromat is computer optimized at infinite conjugate ratios for applications in the near-IR... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Focal Length: 12.3
- Achromat Type: Doublet
- Center Thickness: 10.5
from Newport MKS
The APAC12 Achromatic Aspherical Lens is a 425 to 675 nm antireflection coated (front surface), 0.49 inch (12.5 mm) diameter, N-LaK8 and N-SF57 achromatic doublet lens with an effective focal length of 14.0 mm. The back surface has a molded aspheric polymer cap with a protective seal. This achromat... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Focal Length: 9.89
- Achromat Type: Doublet
- Center Thickness: 8.08
from Newport MKS
The APAC15 Achromatic Aspherical Lens is a 425 to 675 nm antireflection coated (front surface), 0.98 inch (25.0 mm) diameter, N-LaK8 and N-SF57 achromatic doublet lens with an effective focal length of 30.0 mm. The back surface has a molded aspheric polymer cap with a protective seal. This achromat... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Focal Length: 23.21
- Achromat Type: Doublet
- Center Thickness: 11.58
from Newport MKS
The NAC012 Visible Negative Achromatic Doublet Lens is a 400 to 700 nm antireflection coated, 12.5 mm diameter, N-BAF10 and N-SF10 precision achromatic doublet lens with an effective focal length of -15 mm. The negative achromats are commonly used for expanding the beam diameter, increasing focal... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Focal Length: -18.08
- Achromat Type: Doublet
- Center Thickness: 6
from Newport MKS
The NAC010 Visible Negative Achromatic Doublet Lens is a 400 to 700 nm antireflection coated, 6.35 mm diameter, N-BAF10 and N-SF10 precision achromatic doublet lens with an effective focal length of -12.5 mm. The negative achromats are commonly used for expanding the beam diameter, increasing focal... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Focal Length: -12.89
- Achromat Type: Doublet
- Center Thickness: 3
from Ross Optical Industries
Similar to Standard Achromats but smaller in diameter, these Micro Achromats provide good spherical and chromatic correction, enabling them to be used in laser applications. [See More]
- Surface Quality: 40-20 Scratch / Dig
- Lens Application: Infrared (optional feature); Visible; Ultraviolet (optional feature)
- Achromat Type: Doublet
- Focal Length: 6
from Edmund Optics Inc.
Focus Light in Only One Dimension. Design Minimizes Spherical and Chromatic Aberration. Ideal for Creating Line Profiles of Broadband Light Sources. Our TECHSPEC ® Achromatic Cylinder Lenses are similar in design and function to a standard cylinder lens, but have the added benefit of reducing... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Center Thickness: 3
- Focal Length: 100
- Diameter: 12.5
from Thorlabs, Inc.
At Thorlabs, we constantly reinforce our desire to serve at the pleasure of our customers. From this comes our desire to be connected to our industry in a way that far exceeds what would typically be expected of a vendor. Thorlabs lives this core principle by seeking to enhance, at every turn, the... [See More]
- Surface Quality: 10-5 Scratch / Dig; 20-10 Scratch / Dig; 40-20 Scratch / Dig; 60-40 Scratch / Dig
- Lens Application: Infrared; Visible; Ultraviolet
- Achromat Type: Doublet; Triplet
- Focal Length: -100 to 1000
from ECOPTIK (CHANGCHUN) LTD
Achromatic Lenses are used to minimize or eliminate chromatic aberration. The achromatic design also helps minimize spherical aberrations. Achromatic Lenses are ideal for a range of applications, including fluorescence microscopy, image relay, inspection, or spectroscopy. An Achromatic Lens, which... [See More]
- Surface Quality: 20-10 Scratch / Dig; 40-20 Scratch / Dig; 60-40 Scratch / Dig
- Lens Application: Visible
- Achromat Type: Doublet
- Focal Length: 50 to 2000
from Ross Optical Industries
Our catalog Laser Achromats are designed primarily for a diode laser with an 830nm wavelength. They perform well through the near-infrared spectrum. They have been corrected for spherical aberration, coma and astigmatism. They are intended to be used for diode beam manipulation. [See More]
- Surface Quality: 40-20 Scratch / Dig
- Lens Application: Infrared; Visible (optional feature); Ultraviolet (optional feature)
- Achromat Type: Doublet
- Focal Length: 10
from Edmund Optics Inc.
Discounts up to 80% Off. Quantities Extremely Limited. Final Sale, No Returns. Shop the EO Mega Clearance presentations for the hottest deals on component-level products. Quickly browse the best optics, imaging, and photonics deals you will ever see. Quantities are extremely limited and are sold on... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Center Thickness: 2.3
- Focal Length: 25
- Edge Thickness: 2.73
from ECOPTIK (CHANGCHUN) LTD
A cemented cylindrical lens can minimize chromatic aberration, so it can be used to focus a single direction of a multi-color light beam. Unlike a spherical lens that produces a point focusing spot, a cylindrical lens can produce a linear focusing spot. Our cylindrical achromatic doublets are... [See More]
- Surface Quality: 20-10 Scratch / Dig; 40-20 Scratch / Dig; 60-40 Scratch / Dig
- Focal Length: 50 to 2000
- Achromat Type: Triplet
- Center Thickness: 2 to 50
from Ross Optical Industries
Negative Achromats consist of two optical components, a crown and a flint glass lens, cemented together. The crown is usually a bi-concave lens. As is true to all Achromats, they are corrected for color and on-axis spherical aberration. They are used predominantly to extend focal lengths in... [See More]
- Surface Quality: 40-20 Scratch / Dig
- Lens Application: Infrared (optional feature); Visible; Ultraviolet (optional feature)
- Achromat Type: Doublet
- Focal Length: -20