Filter Mount with Sliding Modular Inserts

Overview
Application Idea
Cage Overview
Feedback

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Two CFS1 Filter Mounts with ND Filters for OD Values from 0 to 5
(See the Application Idea Tab for More Information)

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CFS1 Filter Mount with Ø1" Filters and Polarizers

Features

CFS1 Filter Mount with Two CFS1-F1 Modular Inserts for Four Ø1" Optics
CFS1ND Bundle Also Includes Four Absorptive ND Filters (OD 1.0, 2.0, 3.0, and 4.0)
Available Filter Inserts:
- CFS1-F05: SM05-Threaded Filter Insert for Ø1/2" Optics
- CFS1-F1: SM1-Threaded Filter Insert for Ø1" Optics
- CFS1-B: Blank Insert for Custom Machining or Light Blocking
Snap Mechanism Enables Mixing and Matching of Inserts (See Video Below)
Dovetail Track with Detents for Repeatable Positioning
Stackable Design for Mounting of Filters in Series
Filter Inserts Have Blank Labels for Optic Identification
Main Body is Compatible with 30 mm Cage System and SM1 Lens Tubes
8-32 (M4) Tap for Post Mounting

Thorlabs' CFS1 Filter Mount features a modular design that allows sliding inserts with filters or polarization optics to be used with our 30 mm cage system. Each CFS1(/M) Filter Mount comes with two SM1-threaded inserts for up to four Ø1" optics. A blank insert, an SM05-threaded insert, and extra SM1-threaded inserts are available separately. For convenience, we offer the CFS1ND(/M) Mount with four Ø1" Absorptive ND Filters (OD 1.0, 2.0, 3.0, and 4.0) and two SM1-threaded inserts.

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Main bodies can be stacked in series using the included cap screws.

CFS1 Filter Mount Assembly and Stacking Procedure

Main Body
The main body of the CFS1(/M) Filter Mount features a spring-loaded detent mechanism that aligns each filter with the cage system's mechanical axis. The top also offers a setscrew for locking the insert in place. The three adjacent setscrews are used by the positioning detents and should not be adjusted. Multiple filter mounts can also be stacked along the optical path as illustrated in the image to the left and the video to the right.

The main body's face plates offer eight 4-40 taps for compatibility with 30 mm cage systems and internal SM1 (1.035"-40) threading for compatibility with SM1 lens tubes. The body can also be post mounted using the 8-32 (M4) tap on the bottom.

Filter Inserts
The modular design of our filter inserts allows them to be mixed and matched. Inserts can be attached to each other using the hook-and-detent mechanism on the sides of the insert, as illustrated in the video to the right. The inserts must be hooked together while held at 90° with respect to each other. A spring-loaded ball and detent mechanism is designed to keep the filter inserts parallel to each other.

Ø1/2" optics up to 0.28" (7.0 mm) thick and Ø1" optics up to 0.26" (6.6 mm) thick can be mounted inside our CFS1-F05 and
CFS1-F1 Filter Inserts, respectively. Each insert has two SM-threaded optic cells with a lip for mounting optics using the included retaining rings. Thorlabs offers spanner wrenches for tightening the retaining rings. Each filter insert also features a blank label for optic identification. The CFS1-B Blank Insert is designed for custom machining or light blocking applications. This blank insert has an engraved crosshair on one side and a centered dimple on the reverse for aligning a drill bit. It can also be used as an end piece to increase the surface area available for handling.

Stacking CFS1 Filter Mounts with ND Filters

Thorlabs' CFS1 Sliding Filter Mounts can be stacked and loaded with ND filters for various OD combinations. The functionality is similar to our Manual Filter Wheel Mounts. The application idea shown in the photos below uses six Ø1" absorptive ND filters to achieve OD values from 0.1 to 5.0. An optic cell is left empty in each filter mount to allow light to pass through unattenuated. To obtain the OD value combinations in the Combined OD Values table, please insert the filters into each filter mount as indicated in the table. Other combinations are also possible. To view the imperial and metric items used in this setup, refer to the two tables below.

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Exploded View

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Assembled View

Combined OD Values^a
		Filter Mount 'A'
		Empty	NE01B	NE05B	NE10B
Filter Mount 'B'	Empty	0	0.1	0.5	1.0
	NE02B	0.2	0.3	0.7	1.2
	NE20B	2.0	2.1	2.5	3.0
	NE40B	4.0	4.1	4.5	5.0

Filters mounted in this configuration will combine to obtain the OD (optical density) values shown. Other configurations are also possible. Green cells are only intended to highlight whole OD values.

Item #	Qty	Description
CFS1	2	Sliding Filter Mount with Two CFS1-F1 Inserts, 8-32 Tap
NE01B	1	Unmounted Ø25 mm Absorptive ND Filter, Optical Density: 0.1
NE02B	1	Unmounted Ø25 mm Absorptive ND Filter, Optical Density: 0.2
NE05B	1	Unmounted Ø25 mm Absorptive ND Filter, Optical Density: 0.5
NE10B	1	Unmounted Ø25 mm Absorptive ND Filter, Optical Density: 1.0
NE20B	1	Unmounted Ø25 mm Absorptive ND Filter, Optical Density: 2.0
NE40B	1	Unmounted Ø25 mm Absorptive ND Filter, Optical Density: 4.0

Item #	Qty	Description
CFS1/M	2	Sliding Filter Mount with Two CFS1-F1 Inserts, M4 Tap
NE01B	1	Unmounted Ø25 mm Absorptive ND Filter, Optical Density: 0.1
NE02B	1	Unmounted Ø25 mm Absorptive ND Filter, Optical Density: 0.2
NE05B	1	Unmounted Ø25 mm Absorptive ND Filter, Optical Density: 0.5
NE10B	1	Unmounted Ø25 mm Absorptive ND Filter, Optical Density: 1.0
NE20B	1	Unmounted Ø25 mm Absorptive ND Filter, Optical Density: 2.0
NE40B	1	Unmounted Ø25 mm Absorptive ND Filter, Optical Density: 4.0

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 accomodate 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.

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 (2.8")

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
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:

Simon Altenburg (posted 2020-11-03 10:07:35.937)

Which storage box is best suited to store several (at least 5) filter inserts with mounted filters?

llamb (posted 2020-11-06 10:56:17.0)

Thank you for contacting Thorlabs. We do not have a particular storage box/optic case that is compatible with the CFS1-F1 filter inserts. Instead, you may consider one of our larger storage cabinets (such as the ST9) for the filter inserts directly, or otherwise removing the Ø1" optics from the CFS1-F1 filter inserts and storing them in an optic case like the BX0110.

Shengxi Huang (posted 2019-11-21 19:34:10.467)

I wonder if there is a slider similar to CFS1-F1, but smaller in height, that can fit Olympus microscope?

llamb (posted 2019-11-25 09:11:14.0)

Thank you for your feedback. Unfortunately we do not have a similar sliding filter mount for Olympus microscopes. The next best option may be to adapt the CFS1 to your microscope port using one of our adapters here: https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=2665. I have added this idea to our internal product forum in the meantime.

rcprince (posted 2017-01-09 17:51:30.083)

My lab purchased two of these mounts. On both the sliding action of the inserts seems to require more force than one would expect. Can this be remedied?

tfrisch (posted 2017-01-11 01:49:42.0)

Hello, thank you for contacting Thorlabs. The most common cause for difficulty sliding the inserts is that they have been locked in place by the locking set screw on the top of the body, but I will reach out to you directly about your application.

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