[1] Tonouchi, M. Cutting-edge terahertz technology. Nat. Photonics 1, 97-105 (2007). doi: 10.1038/nphoton.2007.3
[2] Jin, Z. M. et al. Accessing the fundamentals of magnetotransport in metals with terahertz probes. Nat. Phys. 11, 761-766 (2015).Article doi: 10.1038/nphys3384
[3] Markelz, A. G., Roitberg, A. & Heilweil, E. J. Pulsed terahertz spectroscopy of DNA, bovine serum albumin and collagen between 0.1 and 2.0 THz. Chem. Phys. Lett. 320, 42-48 (2000). doi: 10.1016/S0009-2614(00)00227-X
[4] Auston, D. H., Cheung, K. P. & Smith, P. R. Picosecond photoconducting Hertzian dipoles. Appl. Phys. Lett. 45, 284-286 (1984). doi: 10.1063/1.95174
[5] Wu, Q. & Zhang, X. C. Free-space electro-optic sampling of terahertz beams. Appl. Phys. Lett. 67, 3523-3525 (1995). doi: 10.1063/1.114909
[6] Smith, P. R., Auston, D. H. & Nuss, M. C. Subpicosecond photoconducting dipole antennas. IEEE J. Quantum Electron. 24, 255-260 (1988). doi: 10.1109/3.121
[7] Fattinger, C. & Grischkowsky, D. Point source terahertz optics. Appl. Phys. Lett. 53, 1480-1482 (1988). doi: 10.1063/1.99971
[8] Gupta, S. et al. Subpicosecond carrier lifetime in GaAs grown by molecular beam epitaxy at low temperatures. Appl. Phys. Lett. 59, 3276-3278 (1991). doi: 10.1063/1.105729
[9] Dhillon, S. S. et al. The 2017 terahertz science and technology Roadmap. J. Phys. D 50, 043001 (2017). doi: 10.1088/1361-6463/50/4/043001
[10] Nandi, U. et al. 1550-nm driven ErAs:In(Al)GaAs photoconductor-based terahertz time domain system with 6.5 THz bandwidth. J. Infrared Millim. Terahertz Waves 39, 340-348 (2018).Article doi: 10.1007/s10762-018-0471-9
[11] Kübler, C. et al. Ultrabroadband detection of multi-terahertz field transients with GaSe electro-optic sensors: approaching the near infrared. Appl. Phys. Lett. 85, 3360-3362 (2004). doi: 10.1063/1.1808232
[12] Ashida, M. Ultra-broadband terahertz wave detection using photoconductive antenna. Jpn J. Appl. Phys. 47, 8221-8225 (2008). doi: 10.1143/JJAP.47.8221
[13] Takayanagi, J. et al. Generation and detection of broadband coherent terahertz radiation using 17-fs ultrashort pulse fiber laser. Opt. Express 16, 12859-12865 (2008). doi: 10.1364/OE.16.012859
[14] Katayama, I. et al. Electric field detection of phase-locked near-infrared pulses using photoconductive antenna. Opt. Express 21, 16248-16254 (2013). doi: 10.1364/OE.21.016248
[15] Shen, Y. C. et al. Generation and detection of ultrabroadband terahertz radiation using photoconductive emitters and receivers. Appl. Phys. Lett. 85, 164 (2004). doi: 10.1063/1.1768313
[16] Hale, P. J. et al. 20 THz broadband generation using semi-insulating GaAs interdigitated photoconductive antennas. Opt. Express 22, 26358-26364 (2014). doi: 10.1364/OE.22.026358
[17] Thomson, M. D., Blank, V. & Roskos, H. G. Terahertz white-light pulses from an air plasma photo-induced by incommensurate two-color optical fields. Opt. Express 18, 23173-23182 (2010). doi: 10.1364/OE.18.023173
[18] Seifert, T. et al. Efficient metallic spintronic emitters of ultrabroadband terahertz radiation. Nat. Photonics 10, 483-488 (2016). doi: 10.1038/nphoton.2016.91
[19] Kim, K. Y. et al. Coherent control of terahertz supercontinuum generation in ultrafast laser-gas interactions. Nat. Photonics 2, 605-609 (2008).Article doi: 10.1038/nphoton.2008.153
[20] Seifert, T. et al. Ultrabroadband single-cycle terahertz pulses with peak fields of 300 kV cm-1 from a metallic spintronic emitter. Appl. Phys. Lett. 110, 252402 (2017). doi: 10.1063/1.4986755
[21] Wu, Y. et al. High-performance THz emitters based on ferromagnetic/nonmagnetic heterostructures. Adv. Mater. 29, 1603031 (2017).Article doi: 10.1002/adma.201603031
[22] Winnerl, S. et al. Terahertz Bessel-Gauss beams of radial and azimuthal polarization from microstructured photoconductive antennas. Opt. Express 17, 1571-1576 (2009). doi: 10.1364/OE.17.001571
[23] Mosley, C. D. W. et al. Scalable interdigitated photoconductive emitters for the electrical modulation of terahertz beams with arbitrary linear polarization. AIP Adv. 9, 045323 (2019). doi: 10.1063/1.5086428
[24] Maussang, K. et al. Large-area photoconductive switches as emitters of terahertz pulses with fully electrically controlled linear polarization. Opt. Express 27, 14784-14797 (2019). doi: 10.1364/OE.27.014784
[25] Singh, A. et al. Gapless broadband terahertz emission from a germanium photoconductive emitter. ACS Photonics 5, 2718-2723 (2018).Article doi: 10.1021/acsphotonics.8b00460
[26] Michel, J., Liu, J. F. & Kimerling, L. C. High-performance Ge-on-Si photodetectors. Nat. Photonics 4, 527-534 (2010). doi: 10.1038/nphoton.2010.157
[27] Jalali, B. & Fathpour, S. Silicon photonics. J. Lightwave Technol. 24, 4600-4615 (2006). doi: 10.1109/JLT.2006.885782
[28] Harter, T. et al. Silicon-plasmonic integrated circuits for terahertz signal generation and coherent detection. Nat. Photonics 12, 625-633 (2018). doi: 10.1038/s41566-018-0237-x
[29] Johnson, L. & Levinstein, H. Infrared properties of gold in germanium. Phys. Rev. 117, 1197-1203 (1960).ADS
[30] Williams, R. L. Carrier lifetimes in n-type gold-doped germanium. J. Phys. Chem. Solids 22, 261-267 (1961). doi: 10.1016/0022-3697(61)90271-2
[31] Dash, W. C. & Newman, R. Intrinsic optical absorption in single-crystal germanium and silicon at 77 K and 300 K. Phys. Rev. 99, 1151-1155 (1955). doi: 10.1103/PhysRev.99.1151
[32] Leitenstorfer, A. et al. Detectors and sources for ultrabroadband electro-optic sampling: experiment and theory. Appl. Phys. Lett. 74, 1516-1518 (1999). doi: 10.1063/1.123601
[33] Ghalgaoui, A. et al. Resonant second-order nonlinear terahertz response of gallium arsenide. Phys. Rev. Lett. 121, 266602 (2018). doi: 10.1103/PhysRevLett.121.266602
[34] Brida, D. et al. Ultrabroadband Er:fiber lasers. Laser Photonics Rev. 8, 409-428 (2014). doi: 10.1002/lpor.201300194
[35] Riek, C. et al. Subcycle quantum electrodynamics. Nature 541, 376-379 (2017). doi: 10.1038/nature21024
[36] Storz, P. et al. Parametric amplification of phase‐locked few‐cycle pulses and ultraviolet harmonics generation in solids at high repetition rate. Laser Photonics Rev. 11, 1700062 (2017). doi: 10.1002/lpor.201700062