title: Long-wavelength (lambda approximately 8-11.5 microm) semiconductor lasers with waveguides based on surface plasmons.
abstract: Laser waveguides based on surface plasmons at a metal-semiconductor interface have been demonstrated by use of quantum cascade (QC) lasers emitting in the 8-11.5-microm wavelength range. The guided modes are transverse magnetic polarized surface waves that propagate at the metal (Pd or Ti-Au)-semiconductor interface between the laser top contact and the active region without the necessity for waveguide cladding layers. The resultant structure has the advantages of a strong decrease in the total layer thickness and a higher confinement factor of the laser-active region compared with those of a conventional layered semiconductor waveguide, and strong coupling to the active material, which could be used in devices such as distributed-feedback lasers. These advantages have to be traded against the disadvantage of increased absorption losses. A peak output power exceeding 25 mW at 90 K and a maximum operating temperature of 150 K were measured for a QC laser with an emission wavelength lambda approximately 8 microm . At lambda approximately 11.5 microm the peak power levels are several milliwatts and the maximum operating temperature is 110 K.
authors: C
authors: C
authors: Sirtori
authors: C
authors: C
authors: Gmachl
authors: F
authors: F
authors: Capasso
authors: J
authors: J
authors: Faist
authors: D L
authors: DL
authors: Sivco
authors: A L
authors: AL
authors: Hutchinson
authors: A Y
authors: AY
authors: Cho