Experiments - Advanced Physical Laboratory

Overview of the available experiments.

Experiments during Sommersemester 2024

Assistant: Ruoming Peng
Room: 02.119 ZAQant
Tel.: 60084
E-Mail: ruoming.peng (at) pi3.uni-stuttgart.de

Room: 1.535    Tel.: 64866

When light hits matter it gets scattered. Mostly this happens in form of elastics scattering (Rayleigh scattering), where the molecule almost instantly reemits the entire absorbed photon energy with the same frequency.
However the excited molecule can absorb (or emit) a (small) part of the photon energy e.g. as molecular vibrations and emit light with a smaller (or larger) frequency. This is called Raman-scattering. The Raman spectrum is characteristic for each molecule and each crystal.
From the energy difference to the incident light and the polarization degree of the scattered light and with the help of group theory one can gain informtation on the atomic structure of the samples. The selection rules for Raman- and IR spectroscopy differ in a way that both methods complement each other very well.
In the experiment the Raman spectra of CHCl3, CHBr3, CdCl3 und CdBr3 are measured. In the setup the light from a HeNe-Laser scattered off the sample is analyzed with a spectrometer.
For the evaluation the measured Raman spectra are compared for these molecules with group theory and assigned to their corresponding group. The Boltzmannn contstant is determined from the intensity ratio between Stokes- and Antistokes lines.

Raman transitions (Stokes and Antistokes), vibrational spectroscopy, group theory of simple symmetries

Assistant: Dumérat, Nicolas
Institute: IGVP
Room: 4.429
Tel.: +49 711 685 69685
E-Mail: nicolas.dumerat (at) igvp.uni-stuttgart.de

Room: PI 218    Tel.: 2480

Over 99% of visible matter in the universe exists in plasma state. On earth natural occurring plasmas are only found in the upper layers of our atmosphere or in natural lightnings. First since the 1920s the research group of Irving Langmuir has devoted themselves to the scientific investigation of plasmas that were generated in the laboratory. Langmuir coined the term “plasma”.
This experiment teaches the work with one of the most important diagnostic tools in plasma physics, the Langmuir-probe. Two different types of probes are used, the single and the double probe, in order to study the plasma parameters of a glow discharge dependent on different discharge parameters. With the Langmuir-probe a number of fundamental properties of a plasma that distinguish it from the other states of matter can be illustrated.

Assistant: Ratnesh Kumar Gupta
Institute: 5.PI
Room: 5.125
Tel.: 64953
E-Mail: rkgupta (at) pi5.physik.uni-stuttgart.de

Room: 1.550    Tel.: 64813

Today nuclear magnetic resonance (NMR) is one of the most important spectroscopic methods in physics, chemistry, biology and medicine. It provides information about the electronic environment of single atoms and their interactions with neighbouring atoms. This information allows the analysis of the structure and dynamics of the sample.
The measuring principle of cw- and pulsed NMR is shown with a simple spectrometer. The characteristic values T1 (spin-lattice relaxation time) and T2 (spin-spin relaxation time) are determined for selected samples.

Key words:
classical and quantum mechanical description of nuclear magnetic resonance, pulse-NMR (rotating coordinate system, FID, spin echo, pulse sequences), measurement of T1 and T2 (spin-spin relaxation, spin-lattice relaxation)

Assistant: Durga Dasari
Institute: 3.PI
Room: 6.546
Tel.: 65228
E-Mail: d.dasari (at) pi3.uni-stuttgart.de

Room: 1.919    Tel.: 64875

One characteristic of classical mechanics is determinism. The dynamics of classical systems are described by differential equations. In the simplest case, these are linear differential equations of second order. For given initial conditions, these can be solved.
However, nonlinear systems might strongly depend on few control parameters. Changing for instance the initial conditions or in the case of friction, one ends up with inhomogeneous differential equations. It is not always possible to solve these equations directly. Even numerical tools can reach the limits of calculability very quickly in this case. The system can no longer be described in global manner and it performs chaotic movements.
The aim of this experiment is to find out what chaotic behavior depends on and to what extent it can be predicted. Two different systems are available for this purpose. One is an inverted pendulum and the other is a Shinriki oscillator.
The pendulum is a purely mechanical system in which chaotic behavior can be directly observed. The Shinriki oscillator is an electrical oscillating circuit that allows for a straightforward and fast analysis of the system.
In both parts of the experiment you will examine basic phenomena of chaotic systems.

Phase-space diagram, Attractor, Bifurcation, Feigenbaum constant, Lyapunov exponent, Kirchhoff´s rules, Shinriki oscillator, Mono-/bistable pendulum, Autocorrelation function

Assistant: Mazzilli, Raffaele
Institute: MPI-FKF
E-Mail: r.mazzilli (at) fkf.mpg.de

Room: 1.939    Tel.: 64864

In a measurement, the demanded information is often given in a time-dependent voltage signal, in the so called time domain. With an oscilloscope, you can record these signals. However, the desired information is often coded in frequency, so one is only interested in particular frequencies. With the aid of a spectrum analyser, the desired signals can be visualized in the frequency domain.
Using examples of simple physical experiments (acoustic resonator, coupled oscillator, fluxgate magnetometer), the experiment demonstrates the versatile possibilities of Fourier methods. Where the oscilloscope just detects noise, you can detect signals in the Fourier space, which differ in amplitude by a factor of 10.000. Aside, a spectrum analyser is excellently qualified for analysing amplitude- or frequency-modulated signals or for the characterisation of nonlinearities.

Assistant: Jiachen Zhao
Institute: 5.PI
Room: 5.160
Tel.: 67470
E-Mail: jzhao (at) pi5.physik.uni-stuttgart.de

Room: 1.519    Tel.: 64866

Imaging techniques are among the most important research methods in science. In order to interpret the images obtained, however, one must have understood the physics on which the image contrast is based. This experiment will familiarize you with the basics of optical microscopy. To do this, you will gradually build your own microscope from simple components and use a modern CCD camera to analyze the contrasts that are characteristic of the various illumination and imaging techniques.

Lenses and lens errors, Fourier optics, Koehler illumination, conjugate planes, Abbe imaging theory, point spread function, contrast transfer function, bright field, and dark field imaging, Zernike phase contrast, fluorescence microscopy, CCD camera.


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