SoSe 20 Exp. Quantum Optics Group / Laboratory of Nano-Optics
Experimental Methods in Nano and Quantum Optics
Exercise 1
1. Derive the rate equations of a three-level system made of a ground, excited and shelving state (see Fig. 1).
Fig. 1 Jablonsky diagram of a three-level system.
A. What are the similarities and the differences with respect to the rate equations of a two- level system (TLS)?
B. Find the steady-state solution of the rate equations.
C. Can you comment, with the help of plots, on the emission rate for weak and strong excitation?
2. Consider a Hanbury-Brown Twiss setup (see Fig. 2). The count rate on one detector is 105 cps and the beamsplitter is 50:50. This count rate corresponds to CW excitation of a TLS with excited-state lifetime 10 ns.
Fig. 2 Hanbury-Brown Twists setup with a 50:50 beamsplitter and two photodetectors.
A. If the binning time is 50 ps, for how long do you need to collect data in order to span the delay time - 10 ns to 10 ns with a signal-to-noise ratio (SNR) of 3? Assume a detector noise of 100 cps.