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Measurement


Scanning Electron Microscope (SEM)

PGL uses an Amray Field Emission scanning electron microscope (SEM) to analyze writing, etching and cleaning results for gratings. The image at right shows a grating etched into a silica layer with a multilayer below. The multilayer is composed of hafnia and silica and extends for 26 layers (not visible in micrograph)

 

 


700 mm Fizeau Interferometer (FToptics)


The 700 mm interferometer is used to evaluate the wavefront flatness of substrates, coatings, and diffraction gratings at 633 nm and 1054 nm.

This instrument uses a spatial-carrier static acquisition (Zygo Flashphase™)method to gather data at the frame rate of the camera. This makes the instrument virtually insensitive to vibration. In addition FTOptics designed the TF mount to rotate the Transmission Flat (TF) so that a full mapping of the critical reference surfaces could be made. This method is outlined in a paper by Flemming Tinker and Michael Brae.

PGL also has a 50 to 100 mm aperture phase-shifting interferometer for measuring high spatial frequency features and small gratings.


Perkin-Elmer Lambda 19 Spectrophotometer


This remarkably versatile spectrophotometer is used for everything from evaluation of complex optical coatings to calibration of optical profilometers. Ours is linked to our network and the results are analyzed using OptiRE™ reverse engineering software. We can measure coating in atmosphere or dry nitrogen and in transmission or at a fixed angle. Note the post it notes around the monitor. Where would we be without Post-it notes.

 


Profilometer


PGL has two optical profilometers to measure film thickness, etch thickness, surface roughness, curvature, and coating stress.The instrument at right is fitted with a purge chamber to allow the samples to be measured in a dry nitrogen atmosphere to simulate vacuum conditions. PGL studies environmental and aging effects of stress in coatings so that the gratings will perform without failure or excessive wavefront deformation in vacuum.The post-it notes on the monitor cannot be seen but, trust us, they are there.

Other instrumentation include a fiber-optic spectrometers, several residual gas monitors, an optical microscope and a laser-based photometer platform. This last device is moved to the Nanoruler for mapping diffraction efficiency on the large gratings.

 

 

 

 

 

 

 

 

 

 

 

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70 Industrial Park Road, Plymouth, MA 02360 Telephone: 508-503-1719 Fax: 508-732-0450 Email: sales@plymouthgrating.com
2007 Plymouth Grating Laboratory

 

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