Quantum Cascade Lasers: From Band Structure Engineering to Commercialization

C. Kumar N. Patel, Ph.D. President & CEO, Pranalytica, Inc. USA
 

Course Description

Quantum Cascade Lasers (QCLs), first demonstrated in 1994 at Bell Labs, are fundamentally different from diode lasers due to their physical operating principle, which makes it possible to design the wavelength over a wide range by simple tailoring of active region layer thicknesses, and to their unipolar nature. These features have revolutionized the field of semiconductor lasers particularly in the mid-infrared region of the spectrum (where molecules have their absorption fingerprints) and in the far-infrared or so called Terahertz spectrum. In these regions until the advent of QCLs there were no semiconductor lasers capable of room temperature operation in pulsed or cw, as well as high output power and stable/wide single mode tunability. The unipolar nature of QCL, combined with the capabilities of bandstructure engineering leads to unprecedented design flexibility and functionality compared to other lasers.
 
In this course, the physics of QCLs, design principles, supported by modeling, will be discussed along with the electronic, optical and thermal properties. State-of-the-art performance in the mid-ir and Terahertz will be reviewed. A broad range of applications (chembio sensing, trace gas analysis, atmospheric chemistry, medical and combustion diagnostics, THz imaging, etc.) and their ongoing commercial development will be discussed. Finally, the course will cover exciting developments such as new light-sources that uses the giant resonant nonlinear susceptibilities of quantum engineered structures to achieve high conversion efficiency at satellite wavelengths, ultrabroadband lasers, ultrashort pulse operation, photonic crystal QCls, optofluidic QCLs as well as QCL incorporating optical antennas on the laser facets to achieve well below wavelength spatial resolution for near field applications.
 

Benefits and Learning Objectives

This course should enable you to:
  • Study intersubband transitions and underlying QC laser physics, operating principles and fundamental differences between standard semiconductor lasers and QC lasers.
  • Understand the rudiments of band structure engineering, including the quantum design of the key types of QC lasers, which have entered real world applications.
  • Discuss experimental device performance, including physical limits, design constraints and comparison with theory.
  • Discuss the basics of QC laser device technology: fabrication process, materials growth options.
  • Illustrate the basics of a chemical sensing system.
  • Discuss applications of state-of the-art mid-infrared QC lasers to sensing and present several examples of QC laser commercialization.
  • Discuss the current research frontier of QC lasers: multiwavelength and broadband devices, nonlinear optical QC lasers, TeraHertz QC lasers, ultrashort pulse QC lasers, optofluidic and photonic crystal QC lasers.
  • Summarize a comprehensive future outlook on QC laser physics, device performance and system applications, and assess the QC laser technology market.

 

Intended Audience

Intermediate Level (Prior knowledge of topic is necessary to appreciate course material.) This course is intended for researchers in industry, academia and government labs; technical managers; graduate students; and qualified undergraduates (mostly senior level) majoring in EE or physics/applied physics.
 

Instructor Biography

Kumar PatelDr. C. Kumar N. Patel is the president and CEO of Pranalytica, a Santa Monica based company that develops and manufactures leading edge quantum cascade lasers and laser systems and high sensitivity sensors for the detection of chemical warfare agents, explosives and industrial and environmental pollutants.

He is the inventor of the carbon dioxide, carbon monoxide, and the Spin-Flip Raman lasers. He pioneered the use of these and other lasers to measure trace gases in difficult environments. He was at AT&T (now Lucent Technologies) Bell Laboratories for thirty-two years and was Executive Director of the Physics Division and of the Materials Research Division. From 1993 to 1999 he was the Vice Chancellor for Research at UCLA. He is currently a Professor of Physics & Astronomy at UCLA.

Dr. Patel was elected to the National Academy of Science in 1974 and the National Academy of Engineering in 1978. He received the National Medal of Science given by the President of the United States in 1996. In recognition of the CO2 laser's importance to the medical field, he has been elected as an Honorary Member of the Gynecologic Laser Surgery Society in 1980 and in 1985 he was elected an Honorary Member of the American Society for Laser Medicine and Surgery. He was inducted into the US National Inventors Hall of Fame in 2012.

He serves on the Board of Directors of Newport Corporation.