Removable Filter Holders and Inserts for 30 mm Cage System

Spring-Loaded Dovetail Design Ensures Repeatable Positioning
Mounts Ø1/2" or Ø1" Optics
SM05 or SM1 Lens Tube Compatible
Blank Plate and Variable Attenuator Inserts Available

Stackable Design

CFH2R

(Cage Plate & Filter Holder Included)

CFH1R

(Cage Plate & Filter Holder Included)

CFH1-F

Extra Ø1/2" Filter Holder

CFH2-V

Variable Attenuator Insert

Related Items

Filters

30 mm Cage Systems

Lens Mounts

Quick-Release Cage Mount

Nanoparticle-Based Linear Polarizers

Lens Tubes

Ø1/2" Posts

Filter Cube for 30 mm Cage Systems

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Overview
Cage Overview
Feedback

Click to Enlarge
Figure 1.1 Filter Holders Allow Quick Swapping of Mounted Filters in Cage System

Alternative Size Options
30 mm Removable Filter Holders
60 mm Removable Filter Holders

Features

Two Filter Holder Mounts Available

Ø1/2" Optics up to 0.18" (5.0 mm) Thick
Ø1" Optics up to 0.31" (8.0 mm) Thick

Easy, One-Hand Operation
Dovetail Design Ensures Good Repeatability
Stackable Design
Extra Filter Holders, Blank Filter Holders, and Variable Attenuator Insert Available Separately

The CFH1R and CFH2R(/M) Removable Filter Holders are based upon a precision dovetail design, ensuring good position stability and repeatability. The CFH1R features an SM05-threaded (0.535"-40) bore that accepts Ø1/2" optics up to 0.18" (5.0 mm) thick, while the CFH2R(/M) has an SM1-threaded (1.035"-40) bore that can accommodate Ø1" optics up to 0.31" (8.0 mm) thick. These mounts are designed for use with a wide variety of Thorlabs' optics such as our Dichroic or Neutral Density Filters, Economy or Concave Mirrors, or Frosted Glass Alignment Disks. The optic is secured in the mount using the included retaining ring.

Extra filter plates are available separately for both the CFH1R Ø1/2" filter mount and the CFH2R(/M) Ø1" filter mount. In addition, blank plates for each mount, also purchased separately, can be used as a manual shutter or machined to suit your specific requirements. The CFH2-V Variable Attenuator Insert can be used in the CFH2R(/M) to partially or completely block light from passing through the aperture.

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 Figure 14A). 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.

Figure 14A An example of the standard cage plate measurements determining cage system compatibility.

Standard Cage System Measurements
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
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:

Alastair Curnock (posted 2025-07-16 09:49:33.07)

Hi Would really like to see a filter holder for 1/2"/12.5mm optics/filters that can fit in the CFH2R/M Cage Plate. ie a version of the CFH2-F with an SM05 threaded mount. would allow me to use 1" or 1/2" optics in the same system without having to change the cage plates

jdelia (posted 2025-07-16 04:05:20.0)

Thank you for contacting Thorlabs, and for providing this valuable feedback. While we currently do not manufacture this, I have passed this request along to our design engineers via our internal suggestion forum for future consideration as a catalog offering.

user (posted 2025-01-16 17:25:33.587)

Hi, I'm currently connecting a CCM1-G01 directly to a CM1-BP108 using CM1-CC. (pellicle beamsplitter to turning mirror using cage cube connector). I'd like to insert a CFH2R between them, but I don't see a way to connect directly, is it possible? I don't want to use cage rods for this for stability reasons.

cdolbashian (posted 2025-01-30 10:25:06.0)

Thank you for reaching out to us with this request. I have contacted you directly to more clearly understand your geometrical configuration.

Gerard Jacobson (posted 2020-01-24 18:03:24.247)

We like the filter holder, the only problem is Thorlabs doesn't carry a storage box that one can place the filter holder in vertically with the label end facing up. Some collegues 3D printed up a holder to store up to 30 mounted filters and used a old detector case to put it in. We can now easily access the mounted filters and ship a filter set in one case. I really think Thorlabs should consider making such a storage box.

YLohia (posted 2020-01-28 08:39:03.0)

Hello Gerard, thank you for your feedback. I have posted your request on our internal engineering forum for further consideration of the filter holder storage box as a future product.

tcohen (posted 2012-04-19 15:33:00.0)

Response from Tim at Thorlabs: Thank you for your feedback! I am discussing your suggestion with our production team. In the meantime we may be able to provide these as custom items. I will contact you with more information.

cbrideau (posted 2012-04-19 14:28:11.0)

I use the 1/2" filter holder, and recently ordered another batch of -F inserts for it. I was surprised and pleased to find you had switched to a longer design as suggested by an earlier poster. I am now interested in the 1" holder, but I'd like to be able to get it with additional filter holders, i.e. CFH2-F as a part. I always need multiple filters for each holder so having more holders available is important to me.

bdada (posted 2011-10-25 23:51:00.0)

Response from Buki at Thorlabs: Thank you for your interest in our cage plates. We will consider your request for a plate that can mount a thicker filter. In the meantime, please consider mounting the thicker filter in one of our 1/2" diameter lens tubes (SM05Lx series) and then threading the lens tube into the cage plate. http://www.thorlabs.com/NewGroupPage9.cfm?ObjectGroup_ID=3306&pn=SM05L03 Please contact TechSupport@thorlabs.com if you have further questions.

user (posted 2011-10-24 13:33:40.0)

A similar holder that can accomodate your thicker (6mm) bandpass filters would also be welcome.

Thorlabs (posted 2010-08-16 16:44:45.0)

Response from Javier at Thorlabs to guyeda: Thank you very much for your feedback. We will modify the filter holder so that the length extends through the entire length of the cage plate.

guyeda (posted 2010-08-13 14:45:59.0)

There should be an option for a filter holder that extends the entire length of the cage plate. As it stands, the gap at the bottom makes this holder ill suited for applications where minimizing stray light is important.

Ø1/2" Removable Filter Holder and Inserts

Ø1/2in Removable Filter Holder and Inserts

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Mounts Ø1/2" Optics Up to 0.18" (5.0 mm) Thick
Compatible with 30 mm Cage Systems
SM05-Threaded on One Side of the Insert
Stackable Design
Post Mountable via 8-32 and M4 Taps

The CFH1R Removable Filter Holder is based upon a precision spring-loaded dovetail design, ensuring good position stability and repeatability. The SM05 (0.535"-40) threaded bore accepts Ø1/2" optics up to 0.18" (5.0 mm) thick, fastened with the included SM05RR Retaining Ring.

Extra SM05-threaded filter plates (CFH1-F) are available separately. In addition, the CFH1-B Blank Plate, also purchased separately, can be used as a manual shutter or machined to suit your specific requirements.

Ø1" Removable Light-Tight Filter Holder and Inserts

Ø1in Removable Light-Tight Filter Holder and Inserts

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Click to Enlarge
Figure 385B Pushing the adjuster down on the CFH2-V quickly closes the shutter.

Click to Enlarge
Figure 385A CFH2R Schematic

Mounts Ø1" Optics Up to 0.31" (8.0 mm) Thick
Compatible with 30 mm Cage Systems
SM1-Threaded on Both Sides
Light-Tight Design
Post Mountable via 8-32 (M4) Tap
Extra Filter Holder, Blank Plate, or Variable Attenuator Insert Available Separately
- Inserts are Compatible with CFH2R(/M) and Previous-Generation CFH2(/M) Filter Holders

Click to Enlarge

The CFH2R(/M) Removable Filter Holder is a light-tight, stackable filter block designed to integrate easily into our 30 mm cage system or to be post mounted on a breadboard. Unlike the CFH1R above, this light-tight design is achieved with a permanent O-ring mounted on the front face and a double-flanged top plate on the removable inner body.

Filter Holder
The filter holder can accommodate Ø1" optics up to 0.31" (8.0 mm) thick and is equipped with SM1-threaded (1.035"-40) faces, making it compatible with any of Thorlabs' SM1-threaded components. The precision, spring-loaded, dovetail design of the removable inner body ensures reproducible positioning and eliminates unwanted movements to ensure repeatability.

The top plate features two laser-engraved boxes for labeling and identification of the mounted optic. Multiple filter holders can be continually stacked in our 30 mm cage system provided an equivalent length of cage rods is available for support. The cage rods can pass through the cage rod clearance holes on the bottom of the CFH2R(/M); however, they thread into the top. Extra SM1-threaded filter plates (CFH2-F) are available separately.

Blank Plate
In addition, the CFH2-B Blank Plate, also purchased separately, can be used as a manual shutter or machined to suit your specific requirements. It features two top-located, laser-engraved boxes for labeling.

Variable Attenuator Insert
The CFH2-V is a variable attenuator insert for the CFH2R(/M) and previous-generation CFH2(/M) holders equipped with a black-oxide-coated variable single-blade shutter to partially or fully block light. The shutter moves vertically from the top across the Ø0.54" aperture and is intended for a maximum 0.50" beam diameter. Shutter position is controlled with a 3/16"-120 adjuster that provides 0.005" shutter translation per revolution; fine adjustments can be performed with the included 5/64" hex key. To quickly close the shutter, press the adjuster down (see Figure 385B); letting go of the adjuster will return the shutter to the set position (within 0.0005"). For best performance, light after the attenuator insert should be coupled into a fiber optic patch cable as the output beam profile will not be circular.