%0 Patent %D 2021 %T Apparatus and method for analyzing a sample %A Markelz, Andrea G %A Acbas, Gheorghe %A Niessen, Katherine A. %X
An apparatus and method for Crystal Anisotropy Terahertz Microscopy (“CATM”) is provided. The apparatus includes an emitter configured to emit a THz pulse and a detector configured to detect the THz pulse after the pulse is transmitted through a sample disposed on a sample surface of the detector. A pulsed radiation generator generates a probe beam to interrogate the detector. The detector may include an electro-optical (“EO”) crystal configured to change in birefringence according to the THz pulse. The sample surface of the detector may have a dielectric coating which is transmissive to THz and reflective to the probe beam. The sample is disposed on the dielectric coating.
%I USPTO %C United States %G eng %U https://patents.google.com/patent/US11125685B2/en %0 Journal Article %J Physical Review B %D 2020 %T Linear dichroism infrared resonance in overdoped, underdoped, and optimally doped cuprate superconductors %A Mukherjee, A. %A Seo, J. %A Arik, M. M. %A Zhang, H. %A Zhang, C. C. %A Kirzhner, T. %A George, D. K. %A Markelz, A. G. %A Armitage, N. P. %A Koren, G. %A Wei, J. Y. T. %A Cerne, J. %K Materials Science %K Physics %X

By measuring the polarization changes in terahertz, infrared, and visible radiation over an extended energy range (3-2330 meV), we observe symmetry breaking in cuprate high-temperature superconductors over wide energy, doping, and temperature ranges. We measure the polarization rotation (Re[theta(F)]) and ellipticity (Im[theta(F)]) of transmitted radiation through thin films as the sample is rotated. We observe a twofold rotational symmetry in theta(F), which is associated with linear dichroism (LD) and occurs when electromagnetic radiation polarized along one direction is absorbed more strongly than radiation polarized in the perpendicular direction. Such polarization anisotropies can be generally associated with symmetry breakings. We measure the amplitude of the LD signal and study its temperature, energy, and doping dependence. The LD signal shows a resonant behavior with a peak in the few hundred meV range, which is coincident with the midinfrared optical feature that has been associated with the formation of the pseudogap state. The strongest LD signal is found in underdoped films, although it is also observed in optimally and overdoped samples. The LD signal is consistent with an electronic nematic order which is decoupled from the crystallographic axes as well as novel magnetoelectric effects.

%B Physical Review B %V 102 %P 6 %8 Aug %@ 2469-9950 %G English %9 Article %M WOS:000562627700004 %] 054520 %R 10.1103/PhysRevB.102.054520 %0 Journal Article %J Journal of Physics D-Applied Physics %D 2017 %T The 2017 terahertz science and technology roadmap %A Dhillon, S. S. %A Vitiello, M. S. %A Linfield, E. H. %A Davies, A. G. %A Hoffmann, M. C. %A Booske, J. %A Paoloni, C. %A Gensch, M. %A Weightman, P. %A Williams, G. P. %A Castro-Camus, E. %A Cumming, D. R. S. %A Simoens, F. %A Escorcia-Carranza, I. %A Grant, J. %A Lucyszyn, S. %A Kuwata-Gonokami, M. %A Konishi, K. %A Koch, M. %A Schmuttenmaer, C. A. %A Cocker, T. L. %A Huber, R. %A Markelz, A. G. %A Taylor, Z. D. %A Wallace, V. P. %A Zeitler, J. A. %A Sibik, J. %A Korter, T. M. %A Ellison, B. %A Rea, S. %A Goldsmith, P. %A Cooper, K. B. %A Appleby, R. %A Pardo, D. %A Huggard, P. G. %A Krozer, V. %A Shams, H. %A Fice, M. %A Renaud, C. %A Seeds, A. %A Stohr, A. %A Naftaly, M. %A Ridler, N. %A Clarke, R. %A Cunningham, J. E. %A Johnston, M. B. %K ex-vivo %K generation %K metal wave-guides %K near-field %K performance %K photoconductive emitters %K Physics %K quantum-cascade lasers %K radiation %K semiconductors %K Terahertz %K thz %K time-domain spectroscopy %X

Science and technologies based on terahertz frequency electromagnetic radiation (100 GHz-30 THz) have developed rapidly over the last 30 years. For most of the 20th Century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to 'real world' applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2017, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 18 sections that cover most of the key areas of THz science and technology. We hope that The 2017 Roadmap on THz science and technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies.

%B Journal of Physics D-Applied Physics %V 50 %P 49 %8 Feb %@ 0022-3727 %G English %9 Review %M WOS:000392153700001 %] 043001 %R https://doi.org/10.1088/1361-6463/50/4/043001 %0 Journal Article %J Nature Communications %D 2014 %T Optical measurements of long-range protein vibrations %A Acbas, G. %A Niessen, K. A. %A Snell, E. H. %A Markelz, A. G. %K absorption %K crystals %K dynamics %K frequency raman-spectra %K hydration %K lysozyme %K motions %K Science & Technology - Other Topics %K sensitivity %K simulations %K spectroscopy %X

Protein biological function depends on structural flexibility and change. From cellular communication through membrane ion channels to oxygen uptake and delivery by haemoglobin, structural changes are critical. It has been suggested that vibrations that extend through the protein play a crucial role in controlling these structural changes. While nature may utilize such long-range vibrations for optimization of biological processes, bench-top characterization of these extended structural motions for engineered biochemistry has been elusive. Here we show the first optical observation of long-range protein vibrational modes. This is achieved by orientation-sensitive terahertz near-field microscopy measurements of chicken egg white lysozyme single crystals. Underdamped modes are found to exist for frequencies >10 cm(-1). The existence of these persisting motions indicates that damping and intermode coupling are weaker than previously assumed. The methodology developed permits protein engineering based on dynamical network optimization.

%B Nature Communications %V 5 %P 7 %8 Jan %@ 2041-1723 %G English %9 Article %M WOS:000331084200018 %] 3076 %R https://doi.org/10.1038/ncomms4076 %0 Conference Proceedings %B Ultrafast Phenomena and Nanophotonics Xvii %D 2013 %T Measuring phonons in protein crystals %A Acbas, G. %A Niessen, K. A. %A George, D. K. %A Snell, E. %A Markelz, A. G. %E Betz, M. %E Elezzabi, A. Y. %E Song, J. J. %E Tsen, K. T. %K correlated motions %K dynamics %K mode %K molecular crystals %K molecular vibrations %K normal modes %K phonons %K protein dynamics %K spectroscopy %K Terahertz %X

Using Terahertz near field microscopy we find orientation dependent narrow band absorption features for lysozyme crystals. Here we discuss identification of protein collective modes associated with the observed features. Using normal mode calculations we find good agreement with several of the measured features, suggesting that the modes arise from internal molecular motions and not crystal phonons. Such internal modes have been associated with protein function.

%B Ultrafast Phenomena and Nanophotonics Xvii %S Proceedings of SPIE %I Spie-Int Soc Optical Engineering %C Bellingham %V 8623 %@ 978-0-8194-9392-7 %G English %M WOS:000322829300003 %R https://doi.org/10.1117/12.2006275 %0 Conference Proceedings %B 2012 37th International Conference on Infrared, Millimeter, and Terahertz Waves %D 2012 %T Orientation Sensitive Terahertz Resonances Observed in Protein Crystals %A Acbas, G. %A Snell, E. %A Markelz, A. G. %K dynamics %K mode %X

A method is presented for measuring anisotropic THz response for small crystals, Crystal Anisotropy Terahertz Microscopy (CATM). Sucrose CATM measurements find the expected anisotropic phonon resonances. CATM measurements of protein crystals find the expected broadband water absorption is suppressed and strong orientation and hydration dependent resonant features.

%B 2012 37th International Conference on Infrared, Millimeter, and Terahertz Waves %S International Conference on Infrared Millimeter and Terahertz Waves %I Ieee %C New York %@ 978-1-4673-1597-5 %G English %M WOS:000330301800120 %R https://doi.org/10.1109/IRMMW-THz.2012.6380168 %0 Journal Article %J Physical Review Letters %D 2012 %T Terahertz Response and Colossal Kerr Rotation from the Surface States of the Topological Insulator Bi2Se3 %A Aguilar, R. V. %A Stier, A. V. %A Liu, W. %A Bilbro, L. S. %A George, D. K. %A Bansal, N. %A Wu, L. %A Cerne, J. %A Markelz, A. G. %A Oh, S. %A Armitage, N. P. %K bi2te3 %K Physics %X

We report the THz response of thin films of the topological insulator Bi2Se3. At low frequencies, transport is essentially thickness independent showing the dominant contribution of the surface electrons. Despite their extended exposure to ambient conditions, these surfaces exhibit robust properties including narrow, almost thickness-independent Drude peaks, and an unprecedentedly large polarization rotation of linearly polarized light reflected in an applied magnetic field. This Kerr rotation can be as large as 65 degrees and can be explained by a cyclotron resonance effect of the surface states.

%B Physical Review Letters %V 108 %P 5 %8 Feb %@ 0031-9007 %G English %9 Article %M WOS:000300576000025 %] 087403 %R https://doi.org/10.1103/physrevlett.108.087403 %0 Journal Article %J Applied Physics LettersApplied Physics LettersApplied Physics Letters %D 2008 %T Terahertz response of quantum point contacts %A Song, J. W. %A Kabir, N. A. %A Kawano, Y. %A Ishibashi, K. %A Aizin, G. R. %A Mourokh, L. %A Reno, J. L. %A Markelz, A. G. %A Bird, J. P. %K detector %K devices %K field-effect transistors %K Physics %K plasma-waves %K radiation %K resonant detection %K subterahertz %K transport %X

We measure a clear terahertz response in the low-temperature conductance of a quantum point contact at 1.4 and 2.5 THz. We show that this photoresponse does not arise from a heating effect, but that it is instead excellently described by a classical model of terahertz-induced gate-voltage rectification. This effect is distinct from the rectification mechanisms that have been studied previously, being determined by the phase-dependent interference of the source drain and gate voltage modulations induced by the terahertz field. (C) 2008 American Institute of Physics.

%B Applied Physics LettersApplied Physics LettersApplied Physics Letters %V 92 %P 3 %8 Jun %@ 0003-6951 %G English %9 Article %M WOS:000256527900083 %] 223115 %! Appl. Phys. Lett.Appl. Phys. Lett. %R https://doi.org/10.1063/1.2938416 %0 Journal Article %J Applied Physics Letters %D 1998 %T Relaxation times in InAs/AlSb quantum wells %A Markelz, A. G. %A Asmar, N. G. %A Gwinn, E. G. %B Applied Physics Letters %V 72 %G eng %U https://aip.scitation.org/doi/abs/10.1063/1.121377 %& 2439 %R 10.1063/1.121377 %0 Journal Article %J Applied Physics Letters %D 1996 %T Interband impact ionization by terahertz illumination of InAs heterostructures %A Markelz, A. G. %A Asmar, N. G. %A Brar, B. %A Gwinn, E. G. %K energy %K far-infrared excitation %K inas/alsb quantum-wells %K inplane %K modulation %K Physics %X

Experimental studies of InAs heterostructures illuminated by far-infrared (FIR) radiation reveal an abrupt increase in the charge density for FIR intensities above a threshold value that rises with increasing frequency. We attribute this charge density rise to interband impact ionization in a regime in which omega tau(m) similar to 1, where tau(m) is the momentum relaxation time, and f=omega/2 pi is the FIR frequency. The dependence of the density rise on the FIR field strength supports this interpretation, and gives threshold fields of 3.7-8.9 kV/cm for the frequency range 0.3-0.66 THz. (C) 1996 American Institute of Physics.

%B Applied Physics Letters %V 69 %P 3975-3977 %8 Dec %@ 0003-6951 %G English %9 Article %M WOS:A1996VY89400005 %! Appl. Phys. Lett.Appl. Phys. Lett. %R 10.1063/1.117842 %0 Journal Article %J Applied Physics Letters %D 1996 %T Temperature of quasi-two-dimensional electron gases under steady-state terahertz drive %A Asmar, N. G. %A Cerne, J. %A Markelz, A. G. %A Gwinn, E. G. %A Sherwin, M. S. %A Campman, K. L. %A Gossard, A. C. %K hot-electrons %K Physics %X

We use photoluminescence to study the time-average energy distribution of electrons in the presence of strong steady-state drive at terahertz (THz) frequencies, in a modulation-doped 125 Angstrom AlGaAs/GaAs square well that is held at low lattice temperature TL. We find that the energy distribution can be characterized by an effective electron temperature, T-e(>T-L), that agrees well with values estimated from the THz-illuminated, dc conductivity. This agreement indicates that under strong THz drive, LO phonon scattering dominates both energy and momentum relaxation; that the carrier distribution maintains a heated, thermal form; and that phonon drift effects are negligible. (C) 1996 American Institute of Physics.

%B Applied Physics Letters %V 68 %P 829-831 %8 Feb %@ 0003-6951 %G English %9 Article %M WOS:A1996TT66300035 %! Appl. Phys. Lett.Appl. Phys. Lett. %R 10.1063/1.116547 %0 Book Section %B Hot Carriers in Semiconductors %D 1996 %T Third Harmonic Generation in a Gaas/Algaas Superlattice in the Bloch Oscillator Regime %A Wanke, M. C. %A Markelz, A. G. %A Unterrainer, K. %A Allen, S. J. %A Bhatt, R. %B Hot Carriers in Semiconductors %I Plenum Press %C New York, NY %V eds. Hess, Karl, Leburton, J.P., Ravaioli, U. %P 161-163 %G eng %U https://www.springer.com/gp/book/9781461380351 %0 Journal Article %J Physical Review B %D 1995 %T QUENCHING OF EXCITONIC QUANTUM-WELL PHOTOLUMINESCENCE BY INTENSE FAR-INFRARED RADIATION - FREE-CARRIER HEATING %A Cerne, J. %A Markelz, A. G. %A Sherwin, M. S. %A Allen, S. J. %A Sundaram, M. %A Gossard, A. C. %A Vanson, P. C. %A Bimberg, D. %B Physical Review B %V 51 %P 5253-5262 %8 Feb 15 %@ 0163-1829 %G eng %M WOS:A1995QP75800064 %R 10.1103/PhysRevB.51.5253 %0 Journal Article %J Physical Review B %D 1995 %T RESONANT-ENERGY RELAXATION OF TERAHERTZ-DRIVEN 2-DIMENSIONAL ELECTRON GASES %A Asmar, N. G. %A Markelz, A. G. %A Gwinn, E. G. %A Cerne, J. %A Sherwin, M. S. %A Campman, K. L. %A Hopkins, P. F. %A Gossard, A. C. %B Physical Review B %V 51 %P 18041-18044 %8 Jun 15 %@ 0163-1829 %G eng %M WOS:A1995RF85700093 %R 10.1103/PhysRevB.51.18041 %0 Conference Proceedings %B Proc. Sixth Intl. Symp. Space Terahertz Tech %D 1995 %T Terahertz grid frequency doublers %A Chiao, Jung-Chih %A Markelz, Andrea %A Li, Yongjun %A Hacker, Jonathan %A Crowe, Thomas %A Allen, James %A Rutledge, David %B Proc. Sixth Intl. Symp. Space Terahertz Tech %I Citeseer %G eng %U https://www.nrao.edu/meetings/isstt/papers/1995/1995199206.pdf %0 Conference Proceedings %B Proceedings of the International Conference on Hot Carriers in Seminconductors %D 1995 %T Third harmonic generation in a GaAs/AlGaAs Superlattice in the Bloch Oscillator Regime %A Wanke, M. C. %A Markelz, A.G. %A Unterrainer, K. %A Allen, S. J. %A Bhatt, R. %B Proceedings of the International Conference on Hot Carriers in Seminconductors %C Chicago, IL %P 161-163 %8 07/1995 %G eng %0 Journal Article %J Solid-State Electronics %D 1994 %T DC TRANSPORT IN INTENSE, INPLANE TERAHERTZ ELECTRIC-FIELDS IN AL(X)GA(1-X)AS HETEROSTRUCTURES AT 300-K %A Asmar, N. G. %A Markelz, A. G. %A Gwinn, E. G. %A Hopkins, P. F. %A Gossard, A. C. %X

We report 300 K studies of the dependence of the in-plane, d.c. conductivity, sigma(d.c.) (E(omega)), of a quasi 2D electron gas on the amplitude E(omega) and frequency of intense, far-infrared fields (omega/2pi = 0.24-3.5 THz). We measure sigma(d.c.) (E(omega) parallel-to E(d.c.)), where E(d.c.) is a small sensing field, and observe a monotonic decrease in sigma(d.c.) with increasing E(omega). Although a simple scaling ansatz collapses the measured sigma(d.c.) (E(omega)) data onto a single curve for frequencies from 0.25-3.45 THz (at low to moderate scaled fields), the decrease in conductivity is substantially more rapid than expected from comparison to similar data taken by Masselink et al. [Solid-St. Electron. 31, 337 (1988)] at 35 GHz. We tentatively attribute this difference to effects of a high-frequency modulation in the electron temperature.

%B Solid-State Electronics %V 37 %P 693-695 %8 Apr-Jun %@ 0038-1101 %G eng %M WOS:A1994NE79600042 %R 10.1016/0038-1101(94)90278-X %0 Journal Article %J Semiconductor Science and Technology %D 1994 %T ENERGY RELAXATION AT THZ FREQUENCIES IN ALXGA1-XAS HETEROSTRUCTURES %A Asmar, N. G. %A Markelz, A. G. %A Gwinn, E. G. %A Hopkins, P. F. %A Gossard, A. C. %X

We report 4.2 K studies of the dependence of the in-plane, DC conductivity of a quasi 2D electron gas on the amplitude E(omega) of applied fields with frequencies from 0.25 THz to 3.5 THz. We analyse the dependence of sigma(DC) on E(omega) assuming that electron-optical phonon scattering dominates energy relaxation, that the absorbed power has a Drude form and that the electron distribution is thermal. This simple analysis is self-consistent: Arrhenius plots of the estimated energy loss rate have a slope near -homega(LO)BAR/k(B) for all frequencies, as expected for energy loss by optical phonon emission. We find that the effective energy relaxation time tau(epsilon) varies with the frequency of the applied field, from tau(epsilon) approximately 4 ps at 0.34 THz to tau(epsilon) approximately 0.3 ps at 3.45 THz. This may indicate a frequency-dependent form for the hot-phonon distribution.

%B Semiconductor Science and Technology %V 9 %P 828-830 %8 May %@ 0268-1242 %G eng %M WOS:A1994NM75300116 %! Semicond. Sci. Technol. %R 10.1088/0268-1242/9/5S/116 %0 Journal Article %J Journal of Luminescence %D 1994 %T PROBING TERAHERTZ DYNAMICS IN SEMICONDUCTOR NANOSTRUCTURES WITH UCSB FREE-ELECTRON LASERS %A Allen, S. J. %A Craig, K. %A Felix, C. L. %A Guimaraes, P. %A Heyman, J. N. %A Kaminski, J. P. %A Keay, B. J. %A Markelz, A. G. %A Ramian, G. %A Scott, J. S. %A Sherwin, M. S. %A Campman, K. L. %A Hopkins, P. F. %A Gossard, A. C. %A Chow, D. %A Lui, M. %A Liu, T. Y. %X

The UCSB free-electron lasers provide kilowatts of continuously tunable radiation from 120 GHz to 4.8 THz. They have the most impact on terahertz science and technology that require a tunable, high power source to explore non-linear dynamics or that sacrifice incident power to recover the linear response of systems with very small cross-section. We describe three experiments that demonstrate the utility of these lasers in experiments on the terahertz dynamics of semiconductor nanostructures: (i) terahertz dynamics of resonant tunneling diodes, (ii) saturation spectroscopy of quantum wells and (iii) photon-assisted tunneling in superlattices.

%B Journal of Luminescence %V 60-1 %P 250-255 %8 Apr %@ 0022-2313 %G eng %M WOS:A1994NR36100065 %R 10.1016/0022-2313(94)90142-2 %0 Journal Article %J Semiconductor Science and Technology %D 1994 %T SUBCUBIC POWER DEPENDENCE OF 3RD-HARMONIC GENERATION FOR INPLANE, FAR-INFRARED EXCITATION OF INAS QUANTUM-WELLS %A Markelz, A. G. %A Asmar, N. G. %A Gwinn, E. G. %A Sherwin, M. S. %A Nguyen, C. %A Kroemer, H. %X

Large third-order, free-carrier nonlinear susceptibilities, chi(3) (to approximately 0.2 esu), and subcubic dependence of the third-harmonic power on the incident intensity, have been observed between 19 cm-1 and 23 cm-1 for InAs/AlSb quantum wells with electron sheet densities between 2.5 x 10(12) cm-2 and 8 X 10(12) cm-2. We find that the transmission of the fundamental, and the samples' DC conductivity, decrease with increasing incident intensity, indicating a large rise in the scattering rate. Using the intensity-dependent transmission to account for absorption in the sample is not sufficient to recover a cubic power law for the third-harmonic intensity. In addition, given the increased scattering rate indicated by the conductivity data, the bulk free-carrier chi(3) due to non-parabolicity should decrease dramatically with increasing fundamental intensity, contrary to our results. Thus, non-parabolicity alone cannot account for the observed third-harmonic response.

%B Semiconductor Science and Technology %V 9 %P 634-637 %8 May %@ 0268-1242 %G eng %M WOS:A1994NM75300063 %! Semicond. Sci. Technol. %R https://doi.org/10.1088/0268-1242/9/5S/063 %0 Conference Proceedings %B SPIE Proceedings %D 1993 %T Far-infrared nonlinear response of electrons in semiconductor nanostructures %A Sherwin, M. S. %A Asmar, N. G. %A Bewley, W. W. %A Craig, K. %A Felix, C. L. %A Galdrikian, B. %A Gwinn, E. G. %A Markelz, A.G. %A Gossard, A. C. %A Hopkins, P. F. %A Sundaram, M. %A Birnir, B. %B SPIE Proceedings %V 1854 %P 36-47 %G eng %0 Journal Article %J Physical Review B %D 1989 %T 8 NEW HIGH-TEMPERATURE SUPERCONDUCTORS WITH THE 1-2-4 STRUCTURE %A Morris, D. E. %A Nickel, J. H. %A Wei, J. Y. T. %A Asmar, N. G. %A Scott, J. S. %A Scheven, U. M. %A Hultgren, C. T. %A Markelz, A. G. %A Post, J. E. %A Heaney, P. J. %A Veblen, D. R. %A Hazen, R. M. %B Physical Review B %V 39 %P 7347-7350 %8 Apr 1 %@ 0163-1829 %G eng %M WOS:A1989T985500074 %R 10.1103/physrevb.39.7347 %0 Journal Article %J Physical Review B %D 1989 %T OXYGEN CONCENTRATION EFFECT ON TC OF THE BI-CA-SR-CU-O SUPERCONDUCTOR %A Morris, D. E. %A Hultgren, C. T. %A Markelz, A. M. %A Wei, J. Y. T. %A Asmar, N. G. %A Nickel, J. H. %B Physical Review B %V 39 %P 6612-6614 %8 Apr 1 %@ 0163-1829 %G eng %M WOS:A1989T985400040 %R https://doi.org/10.1103/physrevb.39.6612