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Ø2" Lens Tubes
Easily Interface with Other Lens Tube Sizes
Lens tubes are ideal for creating compact optical subassemblies. The Ø2" lens tubes sold here can be used to house one or several optical elements, as shown in the diagram of a beam expander below. Optics are separated and secured by retaining rings that are positioned at the desired depth within the lens tube using our SPW604 spanner wrench. Depending on the item purchased, one or two retaining rings will be included (see below for details). Additional retaining rings can be purchased separately. In addition to the Ø2" lens tubes featured on this page, Thorlabs also offers Ø1/2", Ø1", Ø30 mm, and Ø3" versions, each of which is equipped with an SM series thread standard that depends on the tube diameter.
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When an engraved lens tube is attached to another lens tube, the engraving of the connected end is no longer visible.
Thorlabs' Threading Specifications
Thorlabs' lens tubes utilize a series of non-standard threadings. Threading specifications are given below for our SM threadings utilized in our lens tube and cage system components so that you can machine mating components to suit your application. We also offer products with C-Mount and RMS threadings, and the specifications for these threadings are also given below. Please note that other manufacturers may have different tolerances for these threads. For other thread specifications that are not listed here, please contact Tech Support.
These stackable Ø2" Lens Tubes provide a fast and easy means for building compact optical assemblies. Their stackable design and direct interfacing with all SM2-threaded (2.035"-40) components provide flexibility for complex optomechanical assemblies. One SM2RR Retaining Ring is included with each lens tube.
Unlike our Ø2" stackable lens tubes featured above, these Internally Threaded Lens Tubes do not feature a lip at one end nor do they have external SM2 threading. Therefore, optics housed inside can be accessed from both ends. To join these lens tubes end-to-end, use an SM2T2 Lens Tube Coupler. Two SM2RR Retaining Rings are included with each lens tube.
These stackable Ø2" Lens Tubes with side slots provide a fast and easy means for building complex optical assemblies and adjusting the optics without disassembling the setup. Several optics can be inserted into a single tube using multiple SM2RR Retaining Rings. Simply thread the first retaining ring to the desired depth, add the optic, and then use a second retaining ring to secure the optic. Optics can be manually adjusted via the side slots without the use of a spanner wrench. The rotatable slip shield included with the lens tube fits over the lens tube slots to prevent unwanted light from entering the system and to keep the optical setup free from debris. Two retaining rings and one black plastic dust cover are included with each lens tube.
The SM2E60 6" Long Extension Tube is designed to enable longer distances between optical components in lens tube systems that utilize lenses with large focal lengths. Although the ends of these extension tubes are threaded to accept our SM2 series stackable lens tubes, they feature thicker walls than our standard lens tubes, which leads to greater rigidity.
Thorlabs offers four different kinds of SM2 (2.035"-40) retaining rings. The SM2RR is our standard aluminum retaining ring that ships with our Ø2" lens tubes as well as many other Thorlabs components, and is available individually and in packs of 5.
Additionally, SM2RR Retaining Rings can be swapped out for one of the SM2-threaded retaining rings listed in the table to the right. Please keep in mind that due to the increased thickness of some retaining rings, the maximum optic thickness that can be housed inside our standard SM2-compatible mounts will be diminished in some cases.
There are also two spanner wrench choices that can be used with these retaining rings. The SPW604 Spanner Wrench has a hollow design that enables retaining rings for our SM2 series of lens tubes to be adjusted and installed without obscuring the beam path. The handle is knurled for improved grip. Alternatively, the SPW801 Adjustable Spanner Wrench can also be used to position SM2RR or SM2LTRR retaining rings. Please note that the SPW801 wrench can withstand a maximum torque of 80 inch pounds. We also offer the SPB2 Spanner Bit, which can be used with a standard 1/4" hex driver (sold separately). The SPB2 is included as part of the SPB600 Spanner Wrench Bit Kit.