title: Anisotropic contrast optical microscope.
abstract: An optical microscope is described that reveals contrast in the Mueller matrix images of a thin, transparent, or semi-transparent specimen located within an anisotropic object plane (anisotropic filter). The specimen changes the anisotropy of the filter and thereby produces contrast within the Mueller matrix images. Here we use an anisotropic filter composed of a semi-transparent, nanostructured thin film with sub-wavelength thickness placed within the object plane. The sample is illuminated as in common optical microscopy but the light is modulated in its polarization using combinations of linear polarizers and phase plate (compensator) to control and analyze the state of polarization. Direct generalized ellipsometry data analysis approaches permit extraction of fundamental Mueller matrix object plane images dispensing with the need of Fourier expansion methods. Generalized ellipsometry model approaches are used for quantitative image analyses. These images are obtained from sets of multiple images obtained under various polarizer, analyzer, and compensator settings. Up to 16 independent Mueller matrix images can be obtained, while our current setup is limited to 11 images normalized by the unpolarized intensity. We demonstrate the anisotropic contrast optical microscope by measuring lithographically defined micro-patterned anisotropic filters, and we quantify the adsorption of an organic self-assembled monolayer film onto the anisotropic filter. Comparison with an isotropic glass slide demonstrates the image enhancement obtained by our method over microscopy without the use of an anisotropic filter. In our current instrument, we estimate the limit of detection for organic volumetric mass within the object plane of ≈49 fg within ≈7 × 7 μm2object surface area. Compared to a quartz crystal microbalance with dissipation instrumentation, where contemporary limits require a total load of ≈500 pg for detection, the instrumentation demonstrated here improves sensitivity to a total mass required for detection by 4 orders of magnitude. We detail the design and operation principles of the anisotropic contrast optical microscope, and we present further applications to the detection of nanoparticles, to novel approaches for imaging chromatography and to new contrast modalities for observations on living cells.
authors.affiliation: Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: D
authors.initials: D
authors.lastname: Peev
authors.affiliation: Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: T
authors.initials: T
authors.lastname: Hofmann
authors.affiliation: Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: N
authors.initials: N
authors.lastname: Kananizadeh
authors.affiliation: Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: S
authors.initials: S
authors.lastname: Beeram
authors.affiliation: Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: E
authors.initials: E
authors.lastname: Rodriguez
authors.affiliation: Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: S
authors.initials: S
authors.lastname: Wimer
authors.affiliation: Biolin Scientific Inc., Paramus, New Jersey 07652, USA.
authors.forename: K B
authors.initials: KB
authors.lastname: Rodenhausen
authors.affiliation: J. A. Woollam Co., Inc., Lincoln, Nebraska 68508-2243, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Herzinger
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: T
authors.initials: T
authors.lastname: Kasputis
authors.affiliation: Celerion, Inc., Lincoln, Nebraska 68502, USA.
authors.forename: E
authors.initials: E
authors.lastname: Pfaunmiller
authors.affiliation: Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: A
authors.initials: A
authors.lastname: Nguyen
authors.affiliation: Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: R
authors.initials: R
authors.lastname: Korlacki
authors.affiliation: Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: A
authors.initials: A
authors.lastname: Pannier
authors.affiliation: Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: E
authors.initials: E
authors.lastname: Schubert
authors.affiliation: Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: D
authors.initials: D
authors.lastname: Hage
authors.affiliation: Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: M
authors.initials: M
authors.lastname: Schubert
mesh_terms: D016880:Anisotropy; D008853:Microscopy / Q000379:methods*; D008962:Models, Theoretical