For many applications, such as holography, spatial intensity variations in the laser beam are unacceptable. Using these precision pinholes in conjuction with precision positioning and focusing equipment, such as our KT310 Spatial Filter System, creates a "noise" filter, effectively stripping variations in intensity out of a Gaussian beam. Click the "How It Works" tab for specific details.
Principles of Spatial Filters The input Gaussian beam has added to it spatially varying intensity "noise." When a beam is focused by an aspheric lens, the input beam is transformed into a central Gaussian spot (on the optical axis) and side fringes which represent the unwanted "noise." The radial position of the side fringes is proportional to the spatial frequency of the "noise." By centering a pin hole on a central Gaussian spot, the "clean" portion of the beam can pass while the "noise" fringes are blocked.
The diffraction limited spot size at the 99% contour is given by: D = λƒ/r where λ=wavelength, ƒ=focal length and r=input beam 1/e2 radius. A pinhole that is approximately 30% larger is chosen to allow the focused Gaussian spot to pass while blocking the "noise" fringes that are shifted off axis.
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Posted Comments:
Poster: klee
Posted Date: 2009-09-08 12:04:21.0
A response from Ken at Thorlabs to wwarger: We can make 1/2" mounted pinholes as specials. Please send an email to techsupport@thorlabs.com, with the size and quantity that you need, and we will send you a quotation.
Poster: wwarger
Posted Date: 2009-09-03 14:13:47.0
You should consider making 1/2" mounted pinholes to fit in the SM05 mounts and 16 mm cage plates.
Poster: Laurie
Posted Date: 2008-05-27 09:31:50.0
Response from Laurie at Thorlabs to cm1105: The mounted pinholes are fabricated from 302 nonmagnetic stainless steel. If you have additional questions, please dont hesitate to ask.
Poster: cm1105
Posted Date: 2008-05-27 08:41:52.0
of which material are the pinholes made?
Poster: Laurie
Posted Date: 2008-03-18 12:50:14.0
Response from Laurie at Thorlabs to cm1105: The specified dimension in the price box is the diameter of the pinhole. This certainly isnt clear, so we will change the item description to prevent future confusion.
Poster: cm1105
Posted Date: 2008-03-18 12:37:38.0
The specified dimension is the radius or the diameter of the pinhole?
Poster: acable
Posted Date: 2007-10-17 14:50:18.0
Is the CW power rating measured at 10.6um or 1.06um.
Poster: techsupport
Posted Date: 2007-10-17 11:25:37.0
add a definition of the parameter circularity which is mentioned on the overview tab
Copper pinholes, gold-plated one side, flat poly black (98%
emissivity) on the reverse 25 µm Thickness at Aperture Aluminum Housing with 1" Outer Diameter
Damage Threshold 5 x 105 W/mm2, 75 ns Pulse @700 nm 1 x 106 W/mm2, 10 ns Pulse @ 700 nm 1 x 104 W/mm2, CW @ 10.6 µm
Pinhole Diameters
Diameter Tolerance
Pinhole Thickness
10 µm
1 µm
25 µm
25 µm
2.0 µm
50 µm
3.0 µm
These high-power pinholes are designed to withstand high power densities, up to 104 W/mm2 (106 W/cm2) for CW lasers. We recommend aligning the pinhole at low power, increasing the laser to full power after ensuring good throughput.
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Pinhole Fabricated from 302 Nonmagnetic Stainless Steel
P5S
- Ø5 µm Mounted Pinhole, Ideal For Building Spatial Filters
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