Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

1 Publication

Mode-locked short pulses from an 8 μm wavelength semiconductor laser

Hillbrand, J.; Opačcak, N.; Piccardo, M.; Schneider, H.; Strasser, G.; Capasso, F.; Schwarz, B.

Quantum cascade lasers (QCL) have revolutionized the generation of mid-infrared light. Yet, the ultrafast carrier transport in mid-infrared QCLs have so far constituted a seemingly insurmountable obstacle for the formation of ultrashort light pulses. Here, we demonstrate that careful quantum design of the gain medium and control over the intermode beat synchronization enable transform-limited picosecond pulses from QCL frequency combs. Both an interferometric radio-frequency technique and second-order autocorrelation shed light on the pulse dynamics and confirm that mode-locked operation is achieved from threshold to rollover current. Furthermore, we show that both antiphase and in-phase synchronized states exist in QCLs. Being electrically pumped and compact, mode-locked QCLs pave the way towards monolithically integrated non-linear photonics in the molecular fingerprint region beyond 6 μm wavelength.

Keywords: quantum cascade laser; two-photon QWIP; mid-infrared, frequency comb

Publ.-Id: 31624