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In our lab, we use quasiparticles called polaritons to trap infrared light in cavities (size 0.01-1μm) with a size far below the free space wavelength (typically 1-100μm). We couple these polaritons to optical transitions in dimensionally confined quantum mechanical systems, such as quantum wells, wires, and defects. The goal is to assess whether we can overcome the length scale mismatch between the light and the quantum system, enabling new optical components and phenomena. In addition to a fundamental understanding of the optical properties of materials and light, we apply these concepts to develop new optical technology. Examples include thermal cameras, infrared light sources, and infrared gas and liquid sensor systems. These can be used for applications such as measuring heat generation in domestic or commercial spaces, measurement of trace environmental pollutants, and even potentially optical computation. Work in my group is based around a range of materials, including 2D materials (such as graphene), semiconducting materials (such as gallium arsenide), and vibrationally active molecules (including liquids and thin films). I am also committed to building a diverse and inclusive lab where everyone is welcome and supported by both myself and each other. If you are interested in joining or collaborating with us, please reach out to Prof. Folland

Articles

Feature figure

Work on non-destructive spectroscopy of Si nanowires published

Wednesday, November 20, 2024
This paper showed that silicon nanowires fabricated through metal-assisted chemical etching can be characterized using FTIR spectroscopy. Crucially, we show that effective medium models allow us to predict the density of nanowire filling and detect nanometer-thick coatings of oxides. This could act as a versatile platform for infrared spectroscopy.
Herky AFM image

Herky at the Microscale

Tuesday, November 19, 2024
Showing our Hawkeye spirit through microfabrication!
ToC figure

New paper 'Lifetime and Molecular Coupling in Surface Phonon Polariton Resonators'

Friday, May 10, 2024
In this paper, we uncover how the properties of SPhP modes offer some challenges for surface-enhanced sensors. To do so we develop numerical models for understanding both the lifetime and frequency of resonances in silicon carbide resonators. Our results reveal a comparatively narrow range in the center of the Reststrahlen band offers the best candidate spectral range for enhanced sensing.
Presentation

Sid presents honors thesis

Friday, June 16, 2023
Congratulations to Sid, who graduated with honors on research performed in our lab.
GaN characterization

New ONR award to studying GaN using infrared spectroscopy

Friday, June 16, 2023
In this program we will understand the properties of defects and dopants in vertical GaN power electronics
Image from grant

NSF Career - CAREER: Photonics in the Lowest Symmetry Crystals

Tuesday, March 21, 2023
In this project PI Folland will determine how certain classes of crystals can be used to control both direction, and orientation of light waves.
Photo of Sid and Tristan

Tristan and Sid present at SURF 2022

Thursday, March 31, 2022
This past wednesday both Tristan and Sid presented at the University of Iowa Spring Undergraduate Research Festival, on their work which is being performed as part of their shared ICRU fellowship. Congratulations on a great presentation!
Anisotropy

Perspective on anisotropy in nanophotonics published in ACS Photonics

Thursday, March 17, 2022
Publication reviews the possibilities for low symmetry materials for next generation nanophotonics.
PhP detector concept

Perspective on new concepts for infrared optoelectronics

Wednesday, February 23, 2022
Here we discuss how a new generation of infrared optoelectronics could be realized leveraging surface phonon polaritons.
Image of Shear Polaritons

Research on Hyperbolic Shear Polaritons published in Nature

Wednesday, February 23, 2022
Shear phenomena in the infrared dielectric response of a monoclinic crystal are shown to unveil a new polariton class termed hyperbolic shear polariton that can emerge in any low-symmetry monoclinic or triclinic system