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Search Publications by: Craig Copeland (Fed)

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Displaying 1 - 13 of 13

Sub-picoliter Traceability of Microdroplet Gravimetry and Microscopy

December 20, 2021
Lindsay C. C. Elliott, Adam L. Pintar, Craig R. Copeland, Thomas Brian Renegar, Ronald G. Dixson, Robert Ilic, R. Michael Verkouteren, Samuel M. Stavis
Volumetric analysis of single microdroplets is difficult to perform by ensemble gravimetry, whereas optical microscopy is often inaccurate beyond the resolution limit. To address the latter issue, we advance and integrate these complementary methods

Accurate localization microscopy by intrinsic aberration calibration

June 24, 2021
Craig Copeland, Craig McGray, Robert Ilic, Jon Geist, Samuel Stavis
A standard paradigm of localization microscopy involves extension from two to three dimensions by engineering information into emitter images, and approximation of errors resulting from the field dependence of optical aberrations. We invert this standard

Experimental Variation of Magnification Calibration for Localization Microscopy

September 15, 2019
Craig R. Copeland, Bojan R. Ilic, Samuel M. Stavis
We study the experimental variation of a localization microscope due to temporal and thermal factors, enabling elucidation of the discrepancy between transillumination brightfield and epi-illumination fluorescence of an aperture array for magnification

Particle tracking of microelectromechanical system performance and reliability

October 25, 2018
Craig R. Copeland, Craig D. McGray, Jon C. Geist, Samuel M. Stavis
Microelectromechanical systems (MEMS) that require contact of moving parts to implement complex functions have demonstrated critical limits of performance and reliability. Here, we advance a particle tracking method to measure MEMS motion in operando at

Subnanometer localization accuracy in widefield optical microscopy

July 11, 2018
Craig R. Copeland, Jon C. Geist, Craig D. McGray, Vladimir A. Aksyuk, James A. Liddle, Bojan R. Ilic, Samuel M. Stavis
The common assumption that precision is the limit of accuracy in localization microscopy and the typical absence of comprehensive calibration of optical microscopes lead to a widespread issue - overconfidence in measurement results with nanoscale

Aperture Arrays for Subnanometer Calibration of Optical Microscopes

September 28, 2017
Craig Copeland, Craig McGray, Jon Geist, James Alexander Liddle, Robert Ilic, Samuel Stavis
We fabricate and test subresolution aperture arrays as calibration devices for optical localization microscopy. An array pitch with a relative uncertainty of approximately three parts in ten thousand enables magnification calibration with subnanometer

Centroid and Orientation Precision of Localization Microscopy

March 11, 2016
Craig D. McGray, Craig R. Copeland, Samuel M. Stavis, Jon C. Geist
The concept of localization precision, which is essential to localization microscopy, is formally extended from optical point sources to microscopic rigid bodies. Measurement functions are presented to calculate the planar position, orientation, and motion

Characterization of Electrothermal Actuation with Nanometer and Microradian Precision

June 21, 2015
Craig R. Copeland, Craig D. McGray, Jon C. Geist, Vladimir A. Aksyuk, Samuel M. Stavis
A recently introduced particle-tracking method was used to measure the single motion cycles of an electrothermal actuator with nanometer and microradian precision. Driving the actuator with a low-noise input induced deterministic motion that was perfectly