Full Aperture Obstruction Targets

Low-Reflectivity Chrome Targets: Ø50 µm - Ø2500 µm
Chrome OD ≥2.5 for the 400 - 1050 nm Wavelength Range
Ø1" Soda Lime Glass Substrates
>Ø22.86 mm Clear Aperture

R1D50P

Ø50 µm
Obstruction Target

R1D500P

Ø500 µm Obstruction Target

R1D2500P

Ø2500 µm Obstruction Target

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Overview
Graphs
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General Specifications
Substrate	Soda-Lime-Glass
Substrate Thickness	1.5 ± 0.2 mm
Substrate Diameter	25.4 +0.0 / -0.1 mm
Clear Aperture	>22.86 mm
Obstruction Centration Tolerance^a	±0.2 mm
Chrome Optical Density (OD)	≥2.5 (400 - 1050 nm)
Transmitted Wavefront Error	<λ @ 633 nm
Surface Quality	60-40 Scratch-Dig

X and Y tolerance of how centered the obstructions are on the substrate.

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R1D1000P Obstruction Target Secured in the LMR1 Optic Mount

Features

Low-Reflectivity Chrome Obstruction Targets: Ø50 µm - Ø2500 µm
Obstructions Centered on Ø1" Soda Lime Glass Substrates
Chrome OD ≥2.5 (400 - 1050 nm)
>Ø22.86 mm Clear Aperture

Thorlabs' Full Aperture Obstruction Targets consist of a low-reflectivity chrome obstruction centered on a soda-lime glass substrate. The full aperture opening outside the obstruction diameter is >Ø22.86 mm. They are designed for applications such as zero-order beam blocking, investigating stray light, darkfield microscopy, or phase imaging.

The positive obstructions consist of low-reflectivity (AR coated) chrome, which reduces back reflections from the opaque chrome target improving imaging contrast. The AR coating results in < 10% light reflected from the target from 300 - 500 nm. Please see the Graphs tab for data on the AR coating over a wider wavelength range. The chrome target also provides an OD ≥2.5 from 400 - 1050 nm.

The targets can be secured in Ø1" optic mounts; translation mounts are available for precise target alignment along the XY or XYZ axes.

Item #	R1D50P	R1D100P	R1D200P	R1D300P	R1D400P	R1D500P	R1D1000P	R1D1500P	R1D2000P	R1D2500P
Obstruction Diameter	Ø50 µm	Ø100 µm	Ø200 µm	Ø300 µm	Ø400 µm	Ø500 µm	Ø1000 µm	Ø1500 µm	Ø2000 µm	Ø2500 µm
Obstruction Diameter Tolerance	±2 µm		±5 µm				±10 µm	±15 µm	±20 µm

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Click Here to Download Transmission Data
This graph shows the transmission of the soda lime glass substrate.

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Click Here to Download Target Data
This graph shows the spectral reflectance of low-reflectivity chrome (blue line) and soda-lime-glass (red line). The reflectance data of the soda-lime glass accounts for reflection returning from both the front and back surfaces of the substrate. In the 300 - 500 nm range, the low-reflectivity chrome positive obstruction targets reflect <10% of incident light.

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Click Here to Download Target Data
The Optical Density of the Low-Reflectivity Chrome Obstructions vs. Wavelength

Posted Comments:
Ian Oldenburg (posted 2023-10-23 16:39:19.78) Can you make these full apperature obstruction targets on a 2inch optic? cdolbashian (posted 2023-10-27 04:46:42.0) Thank you for reaching out to us with this inquiry. We indeed can make such an obstruction. I have contacted you directly to gather some more information regarding specifications of your custom.