Optic Mounts for 30 mm Cage Cubes
![](https://www.thorlabs.com/Images/GuideImages/6850_OpticsMounts_5.jpg)
- Integrate Dichroic Filters, Prisms, Beamsplitting Cubes,
or Ø1" Optics into 30 mm Cage Systems - Compatible with 30 mm Cage Cube Platforms and Rotating Platforms
B6C
Cube or Prism Clamp
B5C1
Ø1" Optic Holder
FFM1
Dichroic Filter Holder
B6C Holding a Right-Angle
Prism and FFM1 Mounting a
Dichroic Mirror in 30 mm Cage Cubes
Application Idea
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30 mm Cage Cubes and Accessories | ||||
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Cage Cubes | Optic Mounts | Platforms | Rotating Platforms |
Cover Plates |
Features
- Optic Mounts for 30 mm Cage Cubes
- Mount on 30 mm Cage Platforms and Rotating Platforms
These 30 mm-Cage-Cube-Compatible Optic Mounts are ideal for integrating prisms, beamsplitters, dichroic filters, and Ø1" optics into a 30 mm cage cube system. They are compatible with our selection of 30 mm Cage Cube Accessories. See the Application Ideas tab for an example of how to use our cage cubes and accessories to construct a beam combiner with a dichroic mirror as well as a variable attenuation beamsplitter with a polarizing beamsplitting cube.
The FFM1 rectangular filter holder, Ø1" optic mounts, and PM3 clamping arm are designed to mount directly to any of our 30 mm cage cube platforms. The B6C cage cube clamp mounts directly to the top of a C4W or C6WR 30 mm cage cube. This clamp works in conjunction with either a platform or B1C Blank Cover Plate mounted to the bottom of the cage cube.
We also offer a dichroic cage cube with a built-in FFM1 mount.
Combining Two Beams
Our cage system can be used to build an easily adjustable beam combiner. This setup is based on the use of an appropriate dichroic mirror for the wavelengths that need to be combined. One beam needs to be in the transmission band of the dichroic mirror, while the other needs to be in the reflection band. For this application the reflection band laser is 405 nm and the transmission band laser is 635 nm. The DMLP567 is an appropriate dichroic mirror for the two selected wavelengths.
The dichroic mirror is mounted in a B5CT1 threaded Ø1" optic mount and attached to a B4C kinematic platform. The kinematic platform allows for positioning of the beam that is within the reflection band of the dichroic mirror. This assembly is placed within a C4W cage cube with ER cage rods attached to two adjacent faces. One set of cage rods holds a collimator for the reflection band's fiber coupled laser, while the other set of cage rods holds a collimator for the transmission band's fiber coupled laser.
A more complex setup can be built to combine more than two beams by using multiple dichroic mirrors together.
![](https://www.thorlabs.com/images/TabImages/Cage_Dichroic_Mirror_A1-351.jpg)
![Polariztion Key](https://www.thorlabs.com/images/TabImages/Attenuator_Polarization_D1-315.jpg)
Variable Attenuation Beamsplitter
In normal operation, the variable beamsplitter/attenuator utilizes a half-wave plate to rotate the polarization of a previously linearly polarized beam of light. At the beamsplitter interface, p-polarized light will be transmitted, while s-polarized light will be reflected. By choosing the correct orientation with the half-wave plate, one can determine the amount of p-polarized and s-polarized light incident upon the interface (as shown in Figure 1 below).
![Variable Beamsplitter Operation](https://www.thorlabs.com/images/TabImages/Beamsplitter_Operation_D1-476.jpg)
Figure 1. Normal Variable Beamsplitter Operation
The variable attenuation beamsplitter is a common component in many large optical systems and can serve as the basic building block for various applications just as; beam sampling, beam combining, beam splitting, power balance, and reflection isolation. Due to the modular design of the 30 mm cage cube system, this device can be easily integrated into a larger cage cube system. A variable attenuation beamsplitter can function at any wavelength supported by the optics of the system. For this application the optics were chosen for a 670 nm variable beamsplitter.
The polarization beamsplitting cube sits upon a B4CRP precision rotation platform and is held in place with a B6C cage cube clamp. The precision rotation platform allows for precise alignment of the polarization beamsplitting cube relative to the incident laser beam and also yields control over output beam alignment. This assembly is mounted within a C6WR 30 mm cage cube with ER cage rods attached to hold a half-wave plate and rotation mount. The rotation mount is a CRM1PT which is designed for integration into a 30 mm cage system. The precision control over the rotation is particularly useful when attempting to maximize or minimize a beam throughput. The zero-order mounted half-wave plate threads directly onto this rotation mount.
Cage System Overview
The Cage Assembly System provides a convenient way to construct large optomechanical systems with an established line of precision-machined building blocks designed for high flexibility and accurate alignment.
16 mm, 30 mm, and 60 mm Cage System Standards
Thorlabs offers three standards defined by the center-to-center spacing of the cage assembly rods (see image below). The 16 mm cage, 30 mm cage, and 60 mm cage standards are designed to accommodate Ø1/2", Ø1", and Ø2" optics, respectively. Specialized cage plates that allow smaller optics to be directly inserted into our larger cage systems are also available.
Standard Threads
The flexibility of our Cage Assembly System stems from well-defined mounting and thread standards designed to directly interface with a wide range of specialized products. The three most prevalent thread standards are our SM05 Series (0.535"-40 thread), SM1 Series (1.035"-40 thread), and SM2 Series (2.035"-40 thread), all of which were defined to house the industry's most common optic sizes. Essential building blocks, such as our popular lens tubes, directly interface to these standards.
![](https://www.thorlabs.com/images/tabimages/Cage_Plate_Overview_D1-650.gif)
An example of the standard cage plate measurements determining cage system compatibility.
Standard Cage System Measurements | |||
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Cage System | 16 mm | 30 mm | 60 mm |
Thread Series | SM05 | SM1 | SM2 |
Rod to Rod Spacing | 16 mm (0.63") | 30 mm (1.18") | 60 mm (2.36") |
Total Length | 25 mm (0.98") | 41 mm (1.60") | 71.1 mm (2.80") |
Cage Components | ||
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Cage Rods | 16 mm | These rods are used to connect cage plates, optic mounts, and other components in the cage system. The SR Series Cage Rods are compatible with our 16 mm cage systems, while the 30 mm and 60 mm cage systems use ER Series Cage Rods. |
30 mm | ||
60 mm | ||
Cage Plates | 16 mm | These serve as the basic building blocks for a cage system. They may have SM-threaded central bores, smooth bores sized for industry standard optics or to accommodate the outer profile of our SM Series Lens Tubes, or specialized bores for other components such as our FiberPorts. |
30 mm | ||
60 mm | ||
Optic Mounts | 16 mm | Thorlabs offers fixed, kinematic, rotation, and translation mounts specifically designed for our Cage Systems. |
30 mm | ||
60 mm | ||
Cage Cubes | 16 mm | These cubes are useful for housing larger optical components, such as prisms or mirrors, or optics that need to sit at an angle to the beam path, such as beamsplitters. Our cage cubes are available empty or with pre-mounted optics. |
30 mm | ||
60 mm | ||
Replacement Setscrews | Replacement setscrews are offered for our 16 mm (SS4B013, SS4B025, and SS4B038) and 30 mm (SS4MS5 and SS4MS4) cage systems products. | |
Post and Breadboard Mounts and Adapters | Mounting options for cage systems can be found on our Cage System Construction pages. Cage Systems can be mounted either parallel or perpendicular to the table surface. | |
Size Adapters | Cage System Size Adapters can be used to integrate components from different cage system and threading standards. | |
Specialized Components | Thorlabs also produces specialized cage components, such as Filter Wheels, a HeNe Laser Mount, and a FiberPort Cage Plate Adapter, allowing a wide range of our products to be integrated into cage-mounted optical systems. Explore our Cage Systems Visual Navigation Guide to see the full range of Thorlabs' cage components. |
Posted Comments: | |
Katsuya Nozawa
 (posted 2022-10-27 17:03:06.527) The B6C works well to fix a prism on a specified angle.
But I have to loosen the screw to rotate the prism.
I can rotate the prism precisely on B4CRP/M, if you have a spring type clamp pushing the prism on B4CRP/M with free rotation axis. cdolbashian
 (posted 2022-10-31 01:31:04.0) Thank you for the inquiry! I have reached out to you directly to clarify your inquiry! user
 (posted 2021-10-14 11:52:36.673) Hello, I would like to use a FFM1 holder for a 1mm thick rectangular dichroic mirror fixing on a B3C/M baseplate at 45°. Everything will be fixed on a C6WR cube to be inserted in 30mm cage system. However, I was wondering 2 things : 1) is the FFM1 holder rigid enough for stability/safety during transportation ? If not, what can you propose ? 2) what are the angular tolerances for the 45° angle ?
Thanks,
have a nice day,
Rémy. azandani
 (posted 2021-10-26 02:22:24.0) Hello Remy, thank you for contacting Thorlabs. We unfortunately do not have any specs regarding the stability of these products during transportation as that was not part of the intended design process. We also do not have a spec for the tolerance of the 45 degree angle as that is reliant on the end user. user
 (posted 2019-11-06 15:17:15.06) A product similar to this but at 45 deg is needed. If this is mounted to a B4C you lose a fine adjust degree of freedom and only have the coarse loosen screws and rotate by hand to replace it. The closest you come to the needed part is the top of the H45B2. However using this puts the optic surface off of the cube center. It also has clearance issues if through cage rods are used. The suggested part would allow using both the reflected and transmitted beam along the center of a light tight cage cube while retaining both fine degrees of freedom on the reflected beam. llamb
 (posted 2019-11-07 09:56:32.0) Thank you for your feedback about our B5C1 optic holder. While you could consider using the B4CRP(/M) for additional precision in your 45° alignment, a fixed alignment from the optic mount would indeed be helpful. I have added this product idea to our internal engineering forum for further review. I see you did not submit contact information, so feel free to contact techsupport@thorlabs.com if you have any further questions/comments. psonin
 (posted 2015-06-03 18:13:32.07) Hello, I would like to mount a beam-splitter plate in the C4W+B4C cube holder/kinematic platform and the FFM1. However the plate thickness is ~5 mm (20x40x5 mm^3). Can I still use the FFM1 for that? It is indicated that the maximum thickness that it can handle is 3 mm. Or can you please advice another solution? Thanks. besembeson
 (posted 2015-08-28 02:28:19.0) Response from Bweh at Thorlabs USA: Unfortunately the FFM1 will not be suitable and we don't have a solution now for the 5mm thick rectangular plate beamspliter. For a circular one, you can use the B5C (http://www.thorlabs.de/thorproduct.cfm?partnumber=B5C). Outside the cube, there are a few options here: http://www.thorlabs.de/newgrouppage9.cfm?objectgroup_id=1446 elkeneu
 (posted 2015-04-15 08:19:34.26) Dear Thorlabs developer, I want to hold an ultraflat dichroic mirror in one of your cubes. I feel that the mounting system with the 3 fixing screws might be bad for the flatness of the dichroic. I personally think an optics mount using a retaininer ring woulb be more suitable. But there seems to be no such version? cdaly
 (posted 2015-04-20 11:32:24.0) Response from Chris at Thorlabs: If a threaded mount is needed, the CP360R filter holder can actually be used inside of the 30mm cage cube C6W. It's worth noting though that given the fact that the optic is sandwiched between two retaining rings and given the housing's overall length, the clear aperture will be reduced in comparison to the B5C. johannes-2.mueller
 (posted 2014-06-03 15:38:10.107) Hi Thorlabs-Team,
is it possible to fit the FFM1 on the B3C/M? Because the clearance holes on the FFM1 are 25.4 mm apart, while the threads on the B3C/M are only 25.0 mm apart.
Thanks for your help! jlow
 (posted 2014-06-03 10:53:48.0) Response from Jeremy at Thorlabs: The FFM1 will fit onto the B3C/M. The mounting holes on FFM1 are enlarged slightly to accommodate the 25.0mm pitch of the metric base. |
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![CM1-CC Application](https://www.thorlabs.com/images/TabImages/Cage_Dichroic_Holder_A2-150.jpg)
Click to Enlarge FFM1 Dichroic Filter Holder shown mounted to a B3C Cube Platform mounted in a C6WR Cube.
- Holds Dichroic and Other Filters from 26 - 43 mm Long
- Mounts Filters Up to 3.0 mm Thick
- Can Accommodate Filters Up to:
- 1.26" (32 mm) Tall Inside a C4W Cage Cube
- 0.98" (25 mm) Tall Inside a C6WR Cage Cube
- Two Spring-Loaded Clamping Mechanisms Secure Optic's Position
The FFM1 Cage-Compatible Rectangular Filter Holder is specifically designed to hold the rectangular filters. The two included 4-40 (M3) cap screws can be used to secure the holder to Thorlabs' 30 mm Cage Cube Platforms or Rotating Platforms.
If used with a C4W Cage Cube, the mount enables the filter to be placed at a 45o angle with respect to the cube's face and provides a Ø1" clear aperture, which maximizes the usable area of the filter for this configuration. If used with the C6WR Cage Cube, you will only be able to use the top ER rod clearance holes (the bottom ones will be blocked by the platform) and the maximum filter height that can be accommodated is 0.98" (25 mm). Note that the FFM1 Holder is not compatible with our C6WA Platform Adapter.
Rectangular filters up to 3 mm thick can be held using two spring-loaded clamping arms designed to avoid scratching of a filter's interference coating; simply apply a horizontal force to the spring-loaded clamps, seat the optic into the channel created, and release the clamps, which leaves the optic wedged between a stop and a clamp at each end.
If desired, the FFM1 can be mounted directly to a Mini-Series Post using the included cap screws. To mount the filter holder to our Ø1/2" Posts, which feature 8-32 (M4) threading, you'll need an MSA8 thread adapter (MSA4/M for metric Ø1/2" posts).
We also offer the CM1-DCH, which is a dichroic filter mount in our compact 1.5" CM1 cage cube.
![Back to Top Back to Top](https://www.thorlabs.com/images/arrow_Vert.gif)
![](https://www.thorlabs.com/images/TabImages/Rotating_Cage_Platform_A4-150.jpg)
Click to Enlarge B5C1 Mount with Ø1" Optic Mounted on B3CR Platform in a C6WR Cage Cube
![](https://www.thorlabs.com/images/TabImages/30mm_Cage_Mount_A1-150.jpg)
Click to Enlarge
Coated Side of Optics Aligns to Engraved Witness Lines
- Holds Ø1" (25.4 mm) Optics Thicker than 0.12" (3.0 mm)
- Compatible with 30 mm Cage Cube Platforms and Rotating Platforms
The B5C1 Optic Mount uses a setscrew to hold Ø1" optics on our 30 mm Cage Cube Platforms and Rotatable Platforms. The nylon-tipped setscrew that holds the optic in place has a 5/64" (2.0 mm) hex. The mount is attached to imperial cage cube platforms using a 4-40 button head screw (1/16" hex) and washer and to metric cage cube platforms using an M3 screw (2 mm hex) and washer (all mounting hardware included).
When used in a C4W or C6WR cage cube, the mount can center the optic within the cube. This is particularly important when mounting a mirror in the cube. Witness lines are engraved on the sides of the mount for aid in alignment. These witness lines mark the position of the optic's front surface when inserted into the mount with the front face directed towards the screw's mounting slot.
![Back to Top Back to Top](https://www.thorlabs.com/images/arrow_Vert.gif)
![](https://www.thorlabs.com/images/TabImages/Precision_Cage_Platform_A5-150.jpg)
Click to Enlarge B5CT2 Mount with Ø1" Optic Mounted on B4CRP Platform in a C6WR Cage Cube
![](https://www.thorlabs.com/images/TabImages/30mm_Cage_Mount_A2-150.jpg)
Click to Enlarge
Coated Side of Optics Aligns to Engraved Witness Lines
- B5CT1 Holds Ø1" (25.4 mm) Optics up to 0.13" (3.4 mm) Thick
- B5CT2 Holds Ø1" (25.4 mm) Optics up to 0.25" (6.3 mm) Thick
- SM1-Threaded with Included SM1RR Retaining Ring
- Compatible with 30 mm Cage Cube Platforms and Rotating Platforms
The B5CT1 and B5CT2 SM1-threaded Optic Mounts hold Ø1" optics on our 30 mm Cage Cube Platforms and Rotatable Platforms. The B5CT1 and B5CT2 Mounts hold optics up to 0.13" (3.4 mm) or 0.25" (6.3 mm) thick, respectively, using an SM1RR retaining ring (included). The deeper design of the LB5CT2 mount reduces the clear aperture when used with transmissive optics such as beamsplitters, making it ideal for mounting mirrors. Each mount is attached to imperial cage cube platforms using a 4-40 button head screw (1/16" hex) and washer and to metric cage cube platforms using an M3 screw (2 mm) and washer (all mounting hardware included).
When used in a C4W or C6WR cage cube, the mount can center the optic within the cube. This is particularly important when mounting a mirror in the cube. Witness lines are engraved on the sides of the mount for aid in alignment. These witness lines mark the position of the optic's front surface when inserted into the mount with the front face directed towards the screw's mounting slot.
![Back to Top Back to Top](https://www.thorlabs.com/images/arrow_Vert.gif)
![B6C Cage Cube Clamp with Cage Cube](https://www.thorlabs.com/images/TabImages/Cage_Cube_Clamp_A2-250.jpg)
Click to Enlarge
Exploded view of a cage system showing a right-angle prism clamped by the B6C.
- Clamp Objects Within Cage Cubes
- 1/8" Hex Socket Adjuster Clamp with Delrin®-Tipped* Swivel Head
The B6C cage cube clamp, designed for use with our 30 mm cage cubes, features a 1/4"-20 clamp adjuster with a Delrin swivel tip that helps to protect the clamped optic from marring. The clamping mechanism is adjusted with a 1/8” hex socket and designed for use with rectangular objects and other objects with parallel top and bottom surfaces. The clamp of the B6C threads down from its top and pushes down on the object being clamped. Because of this top-down clamping system, the B6C must be used in conjunction with a B1C blank cover plate, platforms, or rotational platforms (see image to the right).
The table above lists the minimum and maximum object thickness that this clamp can hold. For systems that require light tightness, the B6C features an O-ring that, when used with the B1C blank Cover Plate and a 30 mm cage cube, forms a light-tight cage cube.
*Delrin® is a registered trademark of DuPont Polymers, Inc.
Item # | Min Thickness | Max Thickness |
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B6C with B1C | 0.58" (14.8 mm) | 1.28" (32.5 mm) |
B6C with B3C, B3CR, B4C, or B4CRP | 0.45" (11.5 mm) | 1.15" (29.2 mm) |
![Back to Top Back to Top](https://www.thorlabs.com/images/arrow_Vert.gif)
![B3CR and PM3 Holding a Prism](https://www.thorlabs.com/images/tabimages/Cage_Clamping_Arm_A1-150.jpg)
Click to Enlarge The B3CR has 6-32 taps for use with the PM3 to hold a right-angle prism.
- Provides Clamping Force for Our Cage Cube Platforms
- Ideal for Prisms and Beamsplitter Cubes
- Compatible with 30 mm Platforms and Rotating Platforms
Thorlabs' PM3(/M) arms feature a cap screw-activated flexure mechanism to secure the clamping arm to the post, while a nylon-tipped setscrew secures the optic. A Ø0.09" (Ø2.3 mm) hole located near the top of the post allows for its initial tightening with a 5/64" (2 mm) balldriver or hex key. The PM3(/M) arm offers 0.97" (24.6 mm) of vertical travel.
The PM3/M metric clamping arm is compatible with the metric versions of both our 30 mm platforms and rotating platforms. The PM3 imperial clamping arm is compatible with the imperial versions of our 30 mm cage rotating platforms (see image to the right).