Laboratory Course: Photonics and Magnonics

SS 2024

Enrollment key: PM24
Start of enrollment: 03.04.20234
Scope: 2 experiments over 2 or 3 days, 3 SWS, 4.5 LP
Preliminary meeting: Mo. 15.04.2024, 15:00-16:00, SR AP 222
Assignment: Experimentelle Übung: Physikalische Vertiefung (I o. II) Photonik und Magnonik

During the practical course, experiments in the fields of magnetism or optics can be carried out, depending on your interests. From the following offer, 2 experiments with a range of at least 4.5 credit points must be carried out. Appointments are made individually with the corresponding supervisors.

Ferromagnetic resonance (3 days/LP)

Although ferromagnetic resonance (FMR) was experimentally discovered about 60 years ago, it is still one of the most popular methods for studying and characterizing magnetic materials. Basically FMR is the resonance absorption of microwave radiation in a ferromagnetic sample. Students are offered an experiment to study the resonance absorption of microwave radiation with a frequency of 3-5 GHz on a thin ferromagnetic layer. The students learn how to generate or measure a magnetic field, how microwave components (e.g. microwave circulator) work and how to record a resonance curve. The ultimate goal of the experiment is to determine quantities that characterize the ferromagnet (e.g. static magnetization) based on the measured resonance curves.

Frequency doubling in Q-switched Nd:YAG laser (2 or 3 days/LP)

Optically pumped Nd:YAG lasers are often used in industry, research and medicine. In this experiment, a laser is constructed from individual components such as resonator mirrors, pump diode and Nd:YAG crystal. The typical properties of these components are investigated experimentally. The emitted infrared light is then doubled in frequency in a nonlinear crystal. With a Q-switching, short laser pulses can then be generated from the continuous emission. The experiment provides an insight into the functioning and properties of a laser and the nonlinear interaction between light and matter.

Fiber laser (2 or 3 days/LP)

In this experiment, a laser based on glass fibers doped with rare earths is constructed and characterized. The basics of lasers are worked up and the handling and fusion bonding of glass fiber components is learned. Furthermore, possibilities for tuning the output wavelength of the laser or for generating ultrashort laser pulses are investigated and the result is measured.

Light propagation in fibers (2 or 3 days/LP)

The experiment "Light propagation in fibers" is intended to provide a basic understanding of how laser light behaves when propagating through light-conducting structures, using the example of glass fibers. The experimental handling of glass fibers is learned and the properties of a laser beam after propagation through different types of glass fibers are investigated. The polarization of the light as well as its transverse beam profile are of central interest.

Autocorrelation of ultrashort laser pulses (2 or 3 days)

The autocorrelation is an important and everyday tool when dealing with ultrashort laser pulses in the laboratory as it gives information about the duration of the optical pulse which is, due to the time scale in the pico- to femtosecond regime, not directly measurable. In this lab course you will build an autocorrelator yourself, test different detection schemes, and use it to characterize an ultrafast laser.