Multiphotonlithography and measurement system

• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas ; Systems Engineering
• Term: Funded in 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 468910972

To investigate several different nonlinear optical frequency generation processes in silicon based micro- and nanostructures a measurement system will be constructed, which is based on an optical microscope. The system will also be used to fabricate nanophotonic structures lithographically via multi photon polymerisation. In particular two photon polymerisation will be used to create structures for light in- and out-coupling as well as for structuring photo sensitive chalcogenide glasses. Nonlinear frequency generation processes like second harmonic generation and four wave mixing from structured surfaces, thin films, waveguides and micro- and nano resonators will be studied in the near and mid- IR. For this purpose several different laser sources will be attached to the microscope. Especially the excitation in the mid IR at wavelengths above 2200nm is of special interest, since the strong two photon absorption in silicon can be avoided in this way. As a centrepiece therefore a tunable CW-laser system featuring a very narrow line width and large tuning range in the NIR and MIR will be purchased. It will be used to efficiently excite high-Q-resonances (Q>10 000) e.g. in ring or racetrack resonators.The modular upright microscope is designed to allow measurements in reflexion as well as in transmission. The exciting laser light will be coupled through a microscope objective into the on-chip waveguides, while the generated light from the sample is coupled out at a different position and collected with the same objective. The simultaneous white light observation of sample, laser injection and light extraction spots within the same field of view of the microscope allows the correct positioning of the sample achieving optimum light injection as well as convenient adjustment of the light extraction. This will simplify and accelerate the measurements and will lead – in conjunction with special couplers – to an increase in injected light intensity, which is especially important for the efficient excitation of nonlinear optical effects.In summary, the system will facilitate a large variety of nonlinear optical experiments on micro- and nanostructures. Its modular composition is open for future adjustments and extensions and the use of established robust microscope components ensures reliable, reproducible, convenient and faster measurements. The purchase of a tunable MIR-laser complements the existing experimental infrastructure and extends it towards MIR wavelengths allowing the study of efficient nonlinear optical frequency generation processes in silicon and hybrid photonic structures within this spectral range.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Multiphotonenlithographie- und -messsystem
• Instrumentation Group: 0910 Geräte für Ionenimplantation und Halbleiterdotierung
• Applicant Institution: Martin-Luther-Universität Halle-Wittenberg
• Leader: Professor Dr. Jörg Schilling