Optical simulations of a nanowire-based single-photon source

Contacts:

Niels Gregersen, DTU Fotonik, 4525-3789 (ngr@fotonik.dtu.dk)

Torben Roland Nielsen, DTU Fotonik, 4525-6367 (trn@fotonik.dtu.dk)

Jesper Mørk, DTU Fotonik, 4525-5765 (jm@fotonik.dtu.dk)

Sketch of a nanowire single-photon source (left) and numerical simulation of electric field profile (right).

The semiconductor nanowire with an embedded quantum dot can be used as a single-photon source with applications in quantum information and quantum cryptography. However, to efficiently extract single photons from the nanowire is a challenge. In order to design a nanowire with a photon collection efficiency close to 100 % an understanding of the light-matter interaction is necessary and this requires a solution to the electromagnetic problem. First, the light-matter coupling between the QD and the optical field must be evaluated and this is done by calculating the local density of states. Then the light emission from the nanowire must be determined to ensure that the photon is transmitted towards the optical detection system.

Numerical simulation of the electric field profile of the fundamental mode in a nanowire.

In this theoretical project, the students will perform numerical simulations to solve the electromagnetic problem for a realistic nanowire-based single-photon source. Starting with Maxwell’s equations, the students will determine the optical modes of the nanowire. This will be performed using semi-analytical and numerical methods (Femlab). From here the project will continue depending on the students interests.