Features

• 14-Piece Mounted Lens or 50-Piece Unmounted Lens Kit
• Storage Cases Included
• AR-Coated Doublets with One of Three Coatings

Thorlabs offers achromatic doublet kits containing either mounted or unmounted optics. The mounted kits (LSB08 Series) contain 14 of our most popular Ø1" achromatic doublets premounted in SM1-compatible lens cells. Unmounted achromatic doublets of varying diameters are included in the 50-piece kits (ESK50 Series).

The most typical application of achromatic doublet lenses is to reduce the chromatic aberration that is symptomatic of spherical lenses as well as to reduce other aberrations such as coma. Other applications of achromatic doublets include the diffraction limited focusing of laser beams and the focusing or imaging of white light within the design wavelength range.

These achromatic doublets are also available individually by visiting our Achromatic Doublet Navigation.

LSB08 Series of Mounted Achromatic Lenses
Our LSB08 kit comes with 14 of our most popular A- (400 - 700 nm), B- (650 - 1050 nm), or C- (1050 - 1620 nm) coated Ø1" achromatic doublets premounted in SM1-compatible (1.035"-40) lens cells. The mounted optics are housed in a metal box that has room for up to 35 doublets. See the LSB08 Series tab for detailed information on the included optics in each kit.

ESK50 Series of Unmounted Achromatic Lenses
The ESK50 series kits include 50 of our most popular unmounted achromatic doublets housed in a storage case that makes it convenient to accommodate a growing collection of optics. Choose from versions with optics coated with a broadband AR coating for either 400 - 700 nm or 650 - 1050 nm. Detailed information on the included optics can be found under the ESK50-A or ESK50-B tab, respectively. The stackable steel cabinet that houses the unmounted achromatic doublets can be combined with other cabinets in our selection of storage cabinets. Alternatively, the storage cabinets can be integrated into our 19" Rack System.

Contents of LSB08-A Kit*

Contents of LSB08-C Kit*

Contents of ESK501-A Kit*

Contents of ESK50-B Kit*

Revised ESK Drawer Packaging,
Click to Enlarge

Smart Pack

• Minimize CO₂ Footprint
• Reduce Non-Recyclable Packing Materials
• Improve Packaging Integrity
• Saves on Shipping Costs

Thorlabs' Green Initiative is aimed at reducing waste. To that end, we have begun to re-engineer our product packaging. Products listed above are now shipped in re-engineered packaging that minimizes the use of non-recyclable materials.

Over the course of a year, the re-engineered packaging across our product line is projected to reduce our CO₂ footprint by more than 16,184 kg and reduce packaging by over 13,893 pounds! As we move through our product line, we will label re-engineered packages with our green Smart Pack sticker (above).

Spherical Singlet, Best Form, and Achromatic Lens Comparison Guide

Singlets are the most basic form of lens and are available in several types: plano convex, biconvex, plano concave, biconcave, meniscus, and aspheric. Singlets are the most cost-effective lens and perform well. For instance, our standard plano-convex lens will perform nearly as well as a best-form version when the convex side is facing the infinite conjugate.

Best Form lenses, however, are engineered to a higher standard than normal singlets, tending to have better surface quality and flatness than standard singlets. Unlike singlets, these lenses are fabricated using a different radius of curvature on each side of the lens. By doing so, spherical aberration, a common drawback of spherical lenses, can be corrected. Additionally, best form lenses are capable of producing smaller waist sizes than singlets as well as realizing diffraction-limited performance for small input beam diameters. While slightly more expensive than singlets, the spherical aberration correction and improved performance properties make them an alternative to singlets.

Compared to singlets or best form lenses, achromatic lenses are the most complex in that they are actually composed of two or more lenses (e.g., an Achromatic Doublet is comprised from 2 lenses and an achromatic Triplet is designed from 3 lenses). These lenses are either cemented together or have an air gap between them and typically include both positive and negative elements with different indices of refraction. Achromatic lenses are by far the superior lens choice, achieving a tighter focus that is often free of coma and spherical aberration and can also achieve near-diffraction-limited waist sizes. Additionally, achromats are less susceptible to “centration,” meaning that off-lens-axis beams are focused to the same spot as those on axis (simply put, the lens cannot “steer” the beam). The largest benefit of achromatic lenses, however, is their ability to correct for chromatic aberration. Whereas with singlets and best form lenses the focal length is dependent upon wavelength, achromats provide nearly constant focal length across a wide range of wavelengths. Thus, the achromat is ideal for broadband imaging applications and beam shaping.

Choosing a Proper Lens

In general, there are no hard and fast rules as to when you should choose one lens over another. Function mimics necessity, and often times a singlet can serve just as well as a best form or achromat. For instance, with intensity measurements, such as fluorescence measurements, where one may be using a PMT or photodiode, spherical aberration is not a large concern so long as the beam can be focused onto the active area. In this case, the much more economical singlet is preferred. Even in simple systems in which one must correct for spherical aberration, a proper choice of biconvex lens or best fit lens will suffice (such as one-to-one imaging).

For measurements with much higher constraint, however, one may find that a singlet is not sufficient for the given application. Precise imaging and magnification measurements will need to correct for spherical aberration and coma effects. In this case, the achromatic or best form lens is the proper choice. In many single-frequency imaging techniques, a best form lens and appropriately sized beam will suffice. The best form lens will be able to handle high-power concerns and remove spherical aberration. Imaging systems with large magnifications can benefit significantly from the employment of a best form lens over the standard singlet. Additionally, in some cases, best form lenses offer an economical solution to air-gap achromatic lenses (discussed below).

Any broadband technique that utilizes a large wavelength range would benefit from the use of achromatic lenses. In applications where waist size is critical (such as in far off resonant trapping of neutral atoms), achromats are again the proper choice, as they can realize a tighter, near-diffraction-limited waist size. Additionally, the isolation from centration effects will ensure the waist size is in the proper position as the laser beam is moved. In general, achromatic lenses will outperform singlets and best form lenses. While in the past laser power has been a limitation to the use of achromatic lenses, the advent of air-gap achromatic lenses has alleviated that concern. Air-gap achromatic lenses are capable of handling the higher power light sources once reserved for best-form lenses. While significantly more expensive than their best-form counterparts, air-gap achromatic lenses will provide the highest performance, handle high-power applications, and correct for coma, spherical, and chromatic aberration.