Achromatic Doublet / DLB-25.4-180PM
Achromatic doublets are cemented achromats made of two different lenses (Low dispersion positive from crown glass and high dispersion negative from flint glass). The difference of dispersion and shape of both lenses are designed to minimize the chromatic aberrations in blue (486.1nm), green (546.1nm) and red (656.3nm). Therefore, these lenses are able to support the entire visible wavelength spectrum.
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Part Number
DLB-25.4-180PM
¥9,450
◦The spherical aberration of achromatic doublets is better than singlets and minimized at infinite conjugate ratios.
◦Achromatic Doublets are coated on both surfaces with a broadband multi-layer anti-reflection coating for the visible wavelength (400 − 700nm).
◦Set the positive part to the side of the incident parallel beam and put the negative part to the side of the focal point to minimize spherical aberration.
◦The difference in focal length of a lens at each wave length is Chromatic aberration and is due to “dispersion of the glass”, the change in refractive index of glass according to wavelength. This can be corrected by combining glasses with low and high dispersions. Spherical aberration is when a ray enters a lens farther from its optical axis and has a shorter focus than a paraxial focus.
◦Achromatic Doublets are coated on both surfaces with a broadband multi-layer anti-reflection coating for the visible wavelength (400 − 700nm).
◦Set the positive part to the side of the incident parallel beam and put the negative part to the side of the focal point to minimize spherical aberration.
◦The difference in focal length of a lens at each wave length is Chromatic aberration and is due to “dispersion of the glass”, the change in refractive index of glass according to wavelength. This can be corrected by combining glasses with low and high dispersions. Spherical aberration is when a ray enters a lens farther from its optical axis and has a shorter focus than a paraxial focus.
Catalog Code | W3076 |
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RoHS | Yes |
CE | No |
Coating | Broadband Multilayer Antireflection Coating for the Visible |
Edge thickness te | 5.4mm |
Surface Quality (Scratch-Dig) | 40−20 |
Diameter φD | φ25.4mm |
Focal length f | 179.8mm |
Design wavelength | Blue: 486.1nm, Green: 546.1nm, Red: 656.3nm |
Center thickness tc | 6.5mm |
Centration | <1′ |
Clear aperture | 90% of the diameter |
Laser Damage Threshold | 0.3J/cm2 (Laser pulse width 10ns, repetition frequency 20Hz) |
Cement | Ultraviolet Hardened Adhesive |