TERASPARC Terahertz Radiation the FreeElectron Laser Stefano Lupi

TERASPARC: Terahertz Radiation @ the Free-Electron Laser Stefano Lupi (on behalf of the TERASPARC team) Dipartimento di Fisica, Sapienza Università di Roma and INFN

Acknowledgments TERASPARC collaboration: INFN LNF/Roma 1 -2: M. Bellaveglia, E. Chiadroni, P. Calvani, M. Castellano, A. Cianchi, L. Cultrera, G. Di Pirro, M. Ferrario, L. Ficcadenti, G. Gatti, O. Limaj, B. Marchetti, A. Mostacci, E. Pace, A. R. Rossi, L. Palumbo, C. Vaccarezza, and the technical staff: F. Anelli, S. Fioravanti, R. Sorchetti; INFN Torino-Catania: G. Ghigo, R. Gerbaldo, L. Gozzelino, F. Laviano ELETTRA: A. Perucchi LFN-CNR: M. Ortolani

The Terahertz gap 0. 1 THz – 5 THz No electronics, few microwaves generators Vanishing thermal power, few tunable and pulsed lasers.

THz Science and Technology Condensed Matter Physics Life Sciences Macromolecules conformation Secondary and tertiary structure Coherent dynamic development Superconductivity Energy gap Symmetry of the order parameter Direct determination of the superfluid density Dynamics of Cooper pairs Imaging 3 D tomography of dry tissues Near-field sub-wavelenght spatial resolution Low-dimensional materials Dimensionality crossover Non-Fermi liquid normal states Broken symmetry ground states Coherent Phase Transitions Polarons Structural Phase Transitions New Technologies Magnetic sub-ps Dynamics Physical and Analytical Chemistry Polar liquids Hydrogen bond Van der Waals interactions Acoustic-Optic phonon mixing in water Solutions Static and dynamic interactions between solvated ions and solvent THz technologies Array THz detectors Metamaterials Medical diagnostic Skin cancer detection Industrial production Material inspection Production line monitoring Defense industry/Homeland security Detection of explosives and biohazards

Available THz sources Terahertz Lasers n n n Quantum Cascade Lasers (>1 THz); Si- and Ge-lasers (>1. 5 THz); Gas-based lasers (emission only at some given frequencies); Sources based on electron bunch acceleration Narrow Band n Stanford (>3 THz); n Far-Infrared FELs: FELIX, FELBE; n ENEA compact FEL; n Far-IR undulator @ FLASH (Hamburg); n Backward-wave oscillators; Broad Band n Laser Amplifiers: plasma and no linear crystals (no user facility), n Coherent Synchrotron Radiation @ III Generation Machines FEL-based Broad Band (femto-second pulsed) THz Sources

Coherent THz Radiation

Key points for THz coherent emission Sub-ps e-bunches: X-UV-VIS FEL machines routinely produce sub-ps e-bunches. Those bunches emit coherent THz and far-IR radiation and also useful IR-VIS radiation

SPARC OVERVIEW Diagnostic and Matching

Performances Achieved E. Chiadroni et al, Unpublished

THz-Dream 1. THz coherent emission covering a large spectral range: 0. 1 to 30 THz; 2. THz pulse duration lower than 50 fs; 3. Energy/pulse in the 10 -100 m. J range; 4. Far-IR, Mid-IR and VIS probe; 1. Optical coupling between the laser and the THz pulse: THz pump-X probe;

THz Experiments Average Energy (Power) Frequency-Domain Spectroscopy High Energy/Pulse THz Pump- THz Probe non-linear time-domain experiments (THz Pump and IR+VIS Probes using IR+VIS emissions)

High E field associated to the THz pulse n n n The high E (~MV) THz field may induce currents exceeding the critical superconducting current (breaking the Superconducting State with an Electric Field) New kind of transient excitations (out-of-equilibrium supercurrent) avoiding heating effects; How this no-linear state recorces to equilibrium? Ec critical field for the SC Superconducting film, T < Tc Ultrashort, intense (E>1 MV/cm)THz pulses needed!

Magnetic Dynamics with THz pulses A sub-ps THz pulse associates to an E field of 1 MV/cm a B field ~ 0. 5 T THz induced magnetic transitions THz Time Resolved Electron Spin Resonance

Conformational Collective modes of macromolecules water Conformational dynamics of DNA, proteins, lipids, result in collective THz modes. Structural changes are critically important in biological activity thus, if these modes are frozen out, the ability to change structure is lost. Dynamical evolution from disordered conformational states to ordering Large pump THz E field may coherent induce conformational ordering and THz probe may measure its temporal evolution

Femto-Chemistry THz is sensitive to interaction time between a molecule and the surrounding solvent on sub-ps scale Standard high-frequency time-resolved experiments: excite in the UV-VIS a soluted molecule -----> probe in the THz the dynamical effects on solvent High THz fields may induce molecular orientational motion or interionic motion leading to changes in local structures of solvent. This may coherent induce chemical reactions that can be measure with a VIS-UV probe.

Imaging vs Penetration

Chemical Pharmaceutic recognition Background absorption

Imaging of Bio-materials, molecular in-vivo imaging of pathogenesis T. Lffler et al, Optics Express 9, 616 (2001) Ferguson et al, Nature Materials 1, 26 (2002) X. -C Zhang Phys. Med. Biol. 47, 3667 (2002) THz do not subject a biological tissue to harmful radiation and may provide both imaging and spectroscopic information on biological materials. Needs of: 1. High S/N ratio 2. High acquisition rate and resolution 3. THz database for biological tissues 4. High power to increase sensing and penetration 5. Near-field imaging to increase spatial resolution (up to now 10 microns resolution has been obtained)

Far-infrared detector Portable detector housing LN 2 portable cryostats 20 cm Real-time response to Far-infrared Beams (l > 60 mm) Detector layout High TC Superconducting YBa 2 Cu 3 O 7 -x film patterned by photolithography and Heavy-Ion Lithography IEEE Sensors 10 (2010) 863 Physica C 470 (2010) 918 Superconductor Science and Technology 23 (2010) 125008 QCL test source detector housing

II. DEVELOPMENT OF TERAHERTZ CAMERAS • Detectors for the 0. 5 -5 THz range: • Fast response time (microsecond) for multiplexing readout • Monolithic, Fabricated with industrial processes Array prototype fabrication at CNR-IFN in Rome Nanofabrication facility: • Clean room • Electron beam lithography • Thin film deposition • Deep etching THz FOCAL PLANE ARRAY BEAM CONDENSER TARGET BEAM EXPANDER POINT-LIKE IFN-CNR THz M. Ortolani, R. Leoni, SOURCE V. Foglietti, S. Cibella, A. Di Gaspare, E. Giovine, G. Torrioli, F. Evangelisti La Sapienza P. Calvani, S. Lupi, A. Nucara ENEA Frascati A. Doria, G. P. Gallerano, E. Giovenale, A. Petralia, I. Spassovsky, G. Messina SELEX S. I. S. p. A. A. Cetronio, M. Peroni, C. Lanzieri (Finmeccanica group) ERAes s. r. l. B. Mencagli, G. Scrascia, M. Grego