Quantum Cascade Lasers  (QCLs) have witnessed a fast-paced development since their invention in 1994.  The operating wavelength has been extended from the mid-infrared to the far-infrared and now covering a broad range of ~3.2-190 µm. Above room-temperature cw operation has been achieved and the devices are commercially available, opening the door to a wealth of industrial and military applications, particularly in the arenas of chemical and remote sensing, imaging, and communications. Still many exciting areas of exploration remain, ranging from the fundamental performance limits (such as operating temperatures, wavelengths, linewidth, and power) of the QCLs, to the basic understanding of transport, the design of new structures based on electronic and photonic band structure engineering, and the use of new materials.

Similar to the first International QCL workshop held in Seville, Spain (http://www.iiiv.cornell.edu/allwood/spain2004/), this is a by-invitation-only workshop. The objective of this workshop is to be a "think tank", where the top researchers in the field will report on recent exciting developments and brainstorm on promising new directions ranging from questions of basic device physics to applications. We hope that new strategic directions will emerge to provide a roadmap for future development of QCL technology.

The workshop will cover device design, modeling, characterization and testing, as well as the basic QCL transport and optical physics. Applications such as high-resolution spectroscopy, chemical sensing for a variety of diagnostics uses, local oscillators, and imaging will also be discussed.

Discussion emphasizing the following is encouraged:

• Novel applications using QCLs
• Advantages, and limitations of various device designs
• Performance benchmarking against alternative radiation source technologies
• New structures with potential performance improvement over QCLs that have already been developed
• Use of materials such as Antimonide, Silicon Germanium, etc