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Spatial Filter, Compact, Five-Axis, XY θxθy 100TPI, Z 80TPI
2 Weeks
2 Weeks


Spatial Filtering

Objective Lens Recommended Max Input Beam Diameter Calculated Pinhole Diameter* Recommended Pinhole Diameter Recommended Pinhole
M-5X 5.0 mm 32.2 µm 50 µm 910PH-50
M-10X 5.5 mm 20.9 µm 25 µm 910PH-25
* For 1 mm diameter beam at 632.8 mm. For a tutorial, check out Fundamentals of Spatial Filtering.

Spatial filters allow the user to remove random fluctuations from the laser beam’s intensity profile, significantly improving an optical system’s resolution. This laser beam cleanup is especially important for applications such as holography and optical data processing. To produce this clean Gaussian beam, a spatial filter removes the unwanted multiple-order energy peaks, while passing only the central maximum of the diffraction pattern. A spatial filter will remove any additional spatial noise from an optical system, including scattered light in the beam profile caused by dust particles on or around the objective. The spatial filter assembly is made up of the microscope objective, a pinhole aperture and a positioning mechanism.

Intuitive and Easy Alignment

We are sure you will find our 910A Spatial Filter to be the simplest you have ever aligned. Start by simply coarse aligning the unit by holding it up toward a room light. Adjust the transverse position of the pinhole until a spot of light is seen. Center this spot, and then focus it with the knurled focusing ring. This procedure usually assures that some laser light will get through the pinhole when the spatial filter is placed in the optical setup and aligned using the integral iris to center the laser beam. Usually only minor translation of the pinhole and tilting of the whole assembly is needed to bring it into full alignment.

Precision Five-Axis Adjustments

Precise XY translation of the pinhole plus true gimbaling of the entire assembly are achieved with precision 100 TPI screws with new knobs including an integral hex hole, providing smooth, high-resolution motion. Our new zero-free play XY mechanism ensures accurate positioning and enhanced long-term stability. Translation along the optical Z-axis is accomplished without rotation of the pinhole by a knurled ring with a precision 80 TPI thread. Together, these adjustments provide all the flexibility needed to easily orient the spatial filter for optimum performance.

Integral Iris Diaphragm

The objective lens holder on the 910A Series Spatial Filter has an integral iris diaphragm to aid in coarse alignment of the beam and for blocking out stray light.

Independent Adjustment Locks

Independent locks for each axis of translation and rotation securely lock the mechanism, not just the actuator screws, maintaining stable alignment. Engaging or disengaging each lock has negligible influence on the other axes.

Easy Change Pinholes and Objectives

It's easy to change mounted pinholes, which simply thread into the body of the spatial filter. RMS-threaded objective lenses attach to the lens holder, which is then clamped to the positioner. The video shows how to install an M- Series objective lens and 910PH Series mounted pinhole assembly into the 910A. The lens holder has an integral iris diaphragm to aid in coarse alignment of the beam to the spatial filter and for blocking out stray light. Objective lenses and pinholes must be selected and purchased separately. These spatial filters are designed to accommodate select Microscope Objective Lenses models (RMS thread and slim body to fit into 910A's brass cylinder), and all 910PH Series High-Energy Pinhole Apertures.

Optical Table or Post Mounting

For maximum stability when mounting directly to an optical table, these spatial filters are supplied with a slotted base plate that can be attached to either side of the unit. The spatial filter can also be post mounted, using either the 8-32 or M4 threaded hole in the bottom, removing the slotted base plate if desired.