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SM1-Threaded Irises and Shutter
Thorlabs offers internally and externally SM1-Threaded Irises and Beam Shutters for full compatibility with our SM1 Series of Lens Tube and components. This allows for the easy integration of the components into an optomechanical construction. The irises are housed in an anodized aluminum casing. The leaves of the iris pivot within the outer ring housing and are designed for long-lasting performance over several thousand cycles. The SM1SH1 Beam Shutter is lever-activated for opening and closing the aperture.
To see the entire family of irises that each iris presented on this page belongs to, please click on the hyperlinked part number in the table to the right.
Our threaded lever-activated iris diaphragms are continuously variable irises compatible with our Ø1" (Ø25.4 mm) SM1 threaded lens tubes. The individual black spring steel leaves pivot within the outer ring of the iris and are designed to last several thousand cycles. These irises feature an engraved arrow on the top of the housing which indicates the direction the lever must be moved to close the aperture.
Our SM1D12 iris has internal SM1 threading on one side and external SM1 threading on the other side (see drawing to the right). Our SM1D25 iris has internal SM1 (1.035"-40) threading on both sides of the housing (see drawing to the right) as well as a full Ø25 mm aperture. For the minimum and maximum apertures of all of these irises, please see the table in the Overview tab above.
The threaded ring-activated iris diaphragms are specifically designed for use in areas with space constraints where the use of a lever is not possible or practical. For instance, in a cage system the motion of the lever might be constrained by the cage rods. In this case, ring-actuated irises are an excellent solution. The ring actuator turns smoothly and can be locked in position with a setscrew.
The graduated iris uses the same convenient ring-actuated design described above with the addition of a laser-engraved scale, with 0.5 mm increments, indicating the actual diameter of the iris in millimeters to within ±0.5 mm. This is especially useful when the iris is mounted where it is not possible to see the aperture opening, like in closed lens tube system.
The stainless steel leaves of the SM1D12SS iris allow it to be used in higher power applications than traditional spring steel irises. The aperture can be continuously varied from the maximum aperture diameter of 12 mm to a minimum aperture diameter of 0.9 mm. This iris also has internal SM1 (1.035"-40) threading on one side and external SM1 threading on the other, which makes the iris easy to integrate into an SM1 Lens Tube System. The lever-activated diaphragm is designed to provide smooth operation for several thousand cycles. An engraved arrow indicates the position the lever must be in to close the iris. We use a magnetic stainless steel in this iris. Due to its hardness, it offers a longer lifetime than typical non-magnetic stainless steel.
The dual leaf design of the SM1D12SZ allows the iris to be continuously varied from the maximum aperture diameter of 12 mm to completely closed (zero aperture). Our zero-aperture design achieves a completely closed aperture by utilizing two sets of steel leaves mounted in two adjacent planes. This iris also has internal SM1 (1.035"-40) threading on one side and external SM1 threading on the other, which makes the iris easy to integrate into an SM1 Lens Tube System. The iris leaves are made from black spring steel and the lever-activated diaphragm is designed to provide smooth operation for several thousand cycles. These irises feature an engraved arrow on the housing which indicates the direction the lever must be moved to close the aperture. As the aperture gets smaller, it also becomes slightly elliptical due to the design of the iris.
The setscrew on the housing of the iris retains the internal aperture mechanism within the mounting ring and should not be adjusted.
The SM1D12CZ zero-aperture graduated iris provides the added benefit of being able to close completely. The ability to be completely closed is due to the dual layer design of this iris. When the ring is in the closed position, the iris aperture is completely closed (zero aperture), unlike a standard iris, which has a non-zero diameter aperture when in the minimum position. Please note that as the aperture gets smaller, it also becomes slightly elliptical due to the design of the iris.
The SM1D12CZ uses a graduated ring-actuated design with an additional laser-engraved scale, which indicates the actual diameter of the iris in millimeters to within ±0.5 mm. In applications where the iris cannot be easily viewed, this engraved scale greatly simplifies the process of optimizing the iris diameter.
The positions of the SM1SH1 Manual Beam Shutter are conveniently labeled Open and Closed. The lever-actuated shutter is firmly held in position with a precision detent mechanism at both the opened and closed locations. The shutter has internal SM1 lens tube threads on one side and external SM1 threads on the other side, which makes it ideal for use with our lens tube systems and cage assemblies. The shutter has a Ø0.29" (Ø7.2 mm) clear aperture when open.