Deborah L. Sivco

Internally excited acoustic resonator for photoacoustic trace detection.

The quantum-cascade laser can be used as an infrared source for a small portable photoacoustic trace gas detector. The device that we describe uses a quantum-cascade laser without collimating optics mounted inside an acoustic resonator. The laser is positioned in the center of a longitudinal resonator at a pressure antinode and emits radiation along the length of the resonator exciting an axially symmetric longitudinal acoustic mode of an open-ended cylindrical resonator. Experiments are reported with an 8-microm, quasi-cw-modulated, room-temperature laser used to detect N2O.

Intra-Cavity Terahertz Difference-Frequency Generation in Quantum Cascade Lasers

We demonstrate intra-cavity terahertz difference-frequency generation in quantum cascade lasers. A two-wavelength quantum cascade laser with monolithically integrated optical nonlinearity emitting at 7.6 and 8.7 µm was used to generate difference frequency at 60 µm.

Multiwavelength and supercontinuum quantum cascade lasers

Bandstructure engineering of intersubband optical transitions has led to a new class of quantum cascade lasers (QCL) that simultaneously emit multiple wavelengths by suitable tailoring of the gain spectrum of identical cascaded active regions or by cascading of different active regions. Using the larrer approach the first super continuum semiconductor laser has been demonstrated. Bidirectional QCLs as well as preliminary results on intracavity nonlinear optical generation will be discussed.