Fiber Sensors

Prof. Dr. Markus A. SCHMIDT

Email: markus.schmidt@ipht-jena.de
Phone: +49 3641-2-06140

Prof. Markus A. Schmidt holds a professorship in Fiber Optics at Friedrich Schiller University Jena and heads the Department of Fiber Photonics at the Leibniz Institute of Photonic Technology.

His research focuses on advanced optical fibers and hybrid waveguides that combine fiber optics with nanophotonics, microfluidics and functional materials. Current activities include hollow-core waveguides, 3D-nanoprinted meta-optics on fiber end faces, nonlinear frequency conversion, and fiber-based sensing of micro- and nanoscale objects.

Research Areas

Prof. Schmidt's research focuses on novel fiber and waveguide concepts at the interface of fiber optics, nanophotonics and sensing. Research interests include:

Hollow-core fibers and 3D-nanoprinted hollow-core waveguides
Metafibers and functionalization of optical-fiber end faces
Beam shaping, focusing and polarization control by fiber-integrated nanostructures
Nonlinear frequency conversion in microstructured and liquid-core fibers
Optical trapping and detection of micro- and nano-objects
Fiber-based biosensing and optofluidics
Chiral light–matter interaction in structured waveguides
Fiber-integrated platforms for quantum and atomic-photonic applications

Teaching Fields

Prof. Schmidt’s teaching is devoted to the early involvement of young developing scientists in state-of-the-art research. Currently, he holds two courses in:

Fiber optics (summer semester)
Active Photonics Devices (winter semester)

Research Methods

The group combines optical-fiber fabrication with nanophotonic structuring and advanced optical characterization. Methods include:

Design and fabrication of microstructured and multicore optical fibers
Fiber drawing and hybrid material integration
3D laser nanoprinting on fiber end faces and within photonic structures
Fabrication of hollow-core light cages and meta-optical elements
Ultrashort-pulse and nonlinear-optical characterization
Spectral and modal characterization of optical fibers and waveguides
Microscopic tracking of micro- and nano-objects
Optical trapping and particle-motion analysis
Spectroscopic and interferometric characterization of fiber-integrated devices

Left: In-fiber nano-object by means of analyzing Brownian motion. Right: Optofluidic light cage, representing an example of a 3D-nanoprinted hollow waveguide structure.
Illustration: Schmidt research group

Recent Research Results

A major recent research direction is the integration of nanophotonic functionality directly onto optical fibers. Three-dimensional nanoprinting enables metasurfaces and holographic structures to be fabricated on fiber end faces for compact beam shaping and imaging. Achromatic metafibers have demonstrated diffraction-limited focusing across the entire telecommunication band, while more recent dual-core fiber concepts allow the focal position to be tuned dynamically by changing only the optical power distribution inside the fiber [1,2].

Hollow-core “light cages” provide a complementary platform in which light is guided inside an open, low-index core surrounded by nanoprinted dielectric structures. Fiber-integrated light cages combine hollow-core guidance with direct access to the guided field and are promising for sensing, optofluidics and quantum technologies [3]. Recent twisted light-cage geometries additionally enable strong control of optical chirality, including circular birefringence and dichroism [4]. These hollow-core structures are also being explored as interfaces between guided light and atomic systems. In 2026, light storage in cesium-filled light cages demonstrated a scalable platform for multiplexed optical quantum memories [5].

Complementary activities address ultrafast nonlinear frequency conversion and fiber-based detection of nano-objects, linking specialty fiber design with tailored light generation and sensing.

Left: Key features of nonlinear frequency conversion in liquid core fibers. Right: Example of fiber-integrated plasmonic metasurfaces mediated light focusing.
Illustration: Schmidt research group

[1] Ren et al., Nat. Commun. 13, 4183 (2022).
[2] Sun et al., Light Sci. Appl. 14, 237 (2025).
[3] Huang et al., Opt. Lett. 49, 3194 (2024).
[4] Huang et al., Optica 13, 303 (2026).
[5] Gómez-López et al., Light Sci. Appl. 15, 13 (2026).

Link to the Fiber Optics Group of the IPHT JenaExternal link