Project Descriptions

 Laboratory Projects

  • (1) Surface Plasmon Polaritons

    • Surface plasmon polaritons are the resulting excitations of photons coupling to the conduction electrons in metals. These surface modes exist at interfaces between a metal and a dielectric. Their propagation constant along the interface is larger than that of radiation propagating in the dielectric, such that they can be used to confine fields below the diffraction limit. In this experiment, you familiarize yourself with the concept of surface modes and experimentally probe the dispersion relation of surface plasmon polaritons.
    • Literature A to Project 1


  • (2) Photon Anti-Bunching

    • Photon anti-bunching is a true manifestation of the quantum nature of light. It is a statistical measure for the arrival times of photons. In essence, a single emitter (e.g. a quantum dot or molecule) can only emit a single photon at once and hence the probability of the time-separation T between two photons is zero for T=0. In this project, the photon statistics from single quantum dots will be measured using a single photon detector in combination with fast data acquisition software. 
    • Literature A to Project 2
    • Literature B to Project 2

 

  • (3) Optical properties of low-dimensional materials

    • Low-dimensional materials have recently sparked tremendous interest in both research and device applications. This student experiment aims on investigating and understanding how the optical properties of a material change when going from bulk to few atom thick samples. Using standard characterization tools (optical microscopy, atomic force microscopy) as well as photoluminescence measurements, few atom thick flakes of MoS2 will be studied to observe this transition.
    • Literature A to Project 3
    • Literature B to Project 3

  

  • (4) Laser Tweezers and Optical Forces 

      Optical tweezers make use of the gradient forces acting on polarizable particles in an inhomogeneous electric field, such as a focused laser beam. The trapping efficiency depends on how strongly the laser is focused, on its intensity, and on the polarizability of the particle to be trapped. Because of Brownian motion there is no stable trapping in liquids. It is just a question of time until a sufficiently powerful kick from a solution molecule (Maxwell-Boltzmann distribution) leads to the escape of the trapped particle. In this project a laser tweezer will be used to trap micron-sized particles in a solution and the trapping dynamics will be monitored with a quadrant photodetector. The statistics of random Brownian motion in the trap will be recorded and used to derive the trap stiffness and the trap depth.

    • Literature A to Project 4
    • Literature B to Project 4

 

     Theoretical Research Projects

    1. Torque and angular momentum in focused fields
    2. Design of a directional optical antenna


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