RESUMO
We experimentally demonstrated a diode-pumped 587 fs ultrafast laser by using an a-cut Nd:CaYAlO4 crystal. Pumped by an 808 nm fiber-coupled laser diode, a stable continuous-wave mode-locked ultrafast laser was achieved with a semiconductor saturable absorber. The ultrafast pulses had a repetition rate of 75 MHz at the center wavelength of 1080.8 nm. A maximum average output power of the mode-locked laser reached 375 mW delivering a slope efficiency of 9%.
RESUMO
We propose a multiple-range quantum communication channel to realize coherent two-way quantum state transport with high fidelity. In our scheme, an information carrier (a qubit) and its remote partner are both adiabatically coupled to the same data bus, i.e., an N-site tight-binding chain that has a single defect at the center. At the weak interaction regime, our system is effectively equivalent to a three level system of which a coherent superposition of the two carrier states constitutes a dark state. The adiabatic coupling allows a well controllable information exchange timing via the dark state between the two carriers. Numerical results show that our scheme is robust and efficient under practically inevitable perturbative defects of the data bus as well as environmental dephasing noise.
