DOE-NSF-NIH Workshop on Opportunities in THz Science February 12–14, 2004 0 deuterated sucrose 300 K 400 280 K 240 K 300 ] 200 K -1 160 K 200 [cm 120 K α 80 K 100 40 K 10 K 1 0 2 0.5 1.0 1.5 2.0 2.5 Frequency [THz] Opportunities in THz Science Report of a DOE-NSF-NIH Workshop held February 12 – 14, 2004, Arlington, VA M. S. Sherwin, C. A. Schmuttenmaer, and P. H. Bucksbaum, Editors Contributors Co-Chairs: X.-C. Zhang Andrea Markelz Mark Sherwin Mike Martin Phil Bucksbaum Session Chairs Keith Nelson Charles Schmuttenmaer Alan Cheville Todd Smith Andrea Markelz Gwyn Williams Speakers Beth Parks Jim Allen Paul Plancken Other scientific participants Sandra Biedron Jie Shan Mark Allen Larry Carr Rick Averitt Martyn Chamberlain Breakout Session Leaders Louis Brunel Tom Crowe Bob Austin Ted Heilweil Frank DeLucia Dimitri Basov James Heyman Qing Hu David Citrin Peter Jepsen Bob Jones Warren Grundfest Robert Kaindl Bart Noordham Tony Heinz Wim Leemans Ted Norris Jun Kono Laszlo Mihaly Joe Orenstein Daniel Mittleman Chitra Rangan Charles Schmuttenmaer Peter Siegel Harry Tom Karl Unterrainer Toni Taylor Vincent Wallace Lex Van der Meer David Zimdars Ingrid Wilke Panel Members Gwyn Williams Bob Jones Table of Contents Table of Contents .......................................................................................................................... 2 Chapter 1: Executive Summary.................................................................................................. 4 1.1 THz research frontiers and opportunities..................................................................... 4 1.2 Overview ...................................................................................................................... 4 1.3 What is needed .............................................................................................................5 Chapter 2: Introduction .............................................................................................................. 7 2.1 Structure of report ........................................................................................................7 2.2 How to use this report .................................................................................................. 8 Chapter 3: Semiconductors and Their Nanostructures............................................................9 3.0 Executive summary...................................................................................................... 9 3.1 Introduction ................................................................................................................ 10 3.2 Opportunities.............................................................................................................. 15 3.3 Enabling resources and technologies ......................................................................... 22 Chapter 4: Metals, Strongly Correlated Electron Systems, and Insulators ......................... 23 4.0 Executive summary.................................................................................................... 23 4.1 Introduction ................................................................................................................ 24 4.2 Opportunities.............................................................................................................. 32 4.3 What is needed ........................................................................................................... 36 Chapter 5: Physics Applications of THz Radiation ................................................................ 38 5.0 Executive summary.................................................................................................... 38 5.1 Fundamental studies in optical physics...................................................................... 39 5.2 Quantum coherence and control................................................................................. 42 5.3 Atmospheric science, laboratory astrophysics, and molecular collisions .................. 43 5.4 Probing matter under extreme conditions .................................................................. 47 Chapter 6: Opportunities in Chemistry and Biology for THz Science ................................. 50 6.0 Executive summary.................................................................................................... 50 6.1 Introduction ................................................................................................................ 52 6.2 Chemistry ................................................................................................................... 53 6.3 Biology....................................................................................................................... 57 6.4 Terahertz excitation sources: parameters and user needs.......................................... 60 Chapter 7: Medical Opportunities Using THz Radiation ...................................................... 63 7.0 Executive summary.................................................................................................... 63 7.1 Introduction ................................................................................................................ 64 7.2 Rationale..................................................................................................................... 64 7.3 Other areas applicable to medicine ............................................................................ 66 7.4 Potential problems...................................................................................................... 66 7.5 Suggested areas for focus and development .............................................................. 67 Chapter 8: Continuous-Wave, Narrow-Linewidth THz Systems for Spectroscopy and Imaging......................................................................................................................................... 68 8.0 Executive summary.................................................................................................... 68 8.1 Introduction ................................................................................................................ 69 8.2 Sources ....................................................................................................................... 69 8.3 Detectors..................................................................................................................... 71 8.4 Developments needed ................................................................................................ 72 2 8.5 Recommendations ...................................................................................................... 72 Chapter 9: Broad-band Sources and Systems for THz Spectroscopy and Imaging ............ 73 9.0 Executive summary.................................................................................................... 73 9.1 Introduction ................................................................................................................ 73 9.2 Potential technical developments............................................................................... 74 9.3 Requirements..............................................................................................................75 9.4 Increasing the size of the community......................................................................... 79 Chapter 10: Narrow-Band THz Sources for Nonlinear and Non-equilibrium Studies....... 80 10.0 Executive summary.................................................................................................. 80 10.1 Introduction .............................................................................................................. 82 10.2 Comparisons of different types of narrow-band THz sources ................................. 82 10.2.1 Free-electron lasers ............................................................................................... 82 10.2.2 Compact accelerator-based sources, including “table-top” sources..................... 90 10.2.3 Table-top narrow-band THz sources based on ultrafast lasers ............................. 95 10.3 Recommendations .................................................................................................... 98 Chapter 11: Coherent Half- and Few-Cycle Sources for Nonlinear and Non-Equilibrium Studies .......................................................................................................................................... 99 11.0 Executive summary.................................................................................................. 99 11.1 Introduction .............................................................................................................. 99 11.2 Ultrafast time-domain experiments.......................................................................... 99 11.3 High-field phenomena............................................................................................ 100 11.4 Optical elements and diagnostic tools.................................................................... 100 11.5 Sources ................................................................................................................... 101 11.6 Summary ................................................................................................................ 109 11.7 Recommendations .................................................................................................