A room-temperature semiconductor spaser operating near 1.5 µm.

Room temperature spasing of surface plasmon polaritons at 1.46 µm wavelength has been demonstrated by sandwiching a gold-film plasmonic waveguide between optically pumped InGaAs quantum-well gain media. The spaser exhibits gain narrowing, the expected transverse-magnetic polarization, and mirror feedback provided by cleaved facets in a 1-mm long cavity fabricated with a flip-chip approach. The 1.06-µm pump-threshold of ~60 kW/cm2 is in good agreement with calculations. The architecture is readily adaptable to all-electrical operation on an integrated microchip.

Emergent chemical mapping at atomic-column resolution by energy-dispersive x-ray spectroscopy in an aberration-corrected electron microscope.

Chemical mapping at atomic-column resolution by energy-dispersive x-ray spectroscopy in a spherical aberration-corrected scanning transmission electron microscope (STEM) has been demonstrated for the 1.47-A dumbbell structure in InGaAs. The structural imaging and the chemical information in the two-dimensional map are directly correlated. Comparisons with the other existing mapping techniques of STEM in conjunction with electron energy-loss spectroscopy were discussed from aspects of ionization interactions.

Active control and spatial mapping of mid-infrared propagating surface plasmons.

Periodic arrays of subwavelength apertures in metal films have been shown to exhibit strongly enhanced transmission at wavelengths determined by the periodicity of the film as well as the optical properties of the metal and surrounding dielectric material. Here we investigate the coupling between such a grating and a Quantum Cascade Laser. By actively tuning the optical properties of our grating, we control the coupling of laser light to the plasmonic structure, switching our grating from a predominantly transmitting state to a state that allows coupling to propagating surface waves, which can then be imaged on the metallic surface.

Dual wavelength tunable IR dye laser system synchronously pumped by a ND:YAG laser.

We describe a laser system that can provide synchronized pulses matched to the band gap of AlGaAs/GaAs and to InGaAsP/InP.

Broadband ultrafast pulse generation from synchronously pumped dye lasers.

Broadband (up to 70-nm) femtosecond to picosecond laser pulses are generated from synchronously pumped dye lasers. We demonstrate that such well-collimated broadband laser pulses can facilitate pump-and-probe experiments by measuring the evolution of the transmission spectrum of a Schott RG830 doped glass after being pumped by 1.4-psec, 532-nm pulses.

Continuous-wave synchronously pumped femtosecond dye laser at 1.3 microm.

We report a synchronously pumped, cw mode-locked, near-IR dye laser based on the Kodak Q-switch dye No. 5. Benzyl alcohol is used as the solvent to form a flowing dye jet. Synchronously pumped by 2-psec, 950-mW, compressed pulses of a Nd:YAG laser, the dye laser can be tuned from 1210 to 1340 nm with a maximum output of 5 mW and a pulse duration of 600 fsec.