Home
“ Education is an admirable thing, but it is well to remember from time to time that nothing that is worth knowing can be taught. ”
- Oscar Wilde

Faculty

Photo
Timothy Benseman, Assistant Professor

TERAHERTZ LASERS & SIGNAL PROCESSING

Contact:
itomht.yebsnmenaq@.cucyne.ud
(718) 997-3369, SB B208
Education:
- Ph.D in Physics, University of Cambridge, United Kingdom, 2007.
- BScHons, MSc in Physics, Victoria University of Wellington, New Zealand, 2002, 2003.

Research

Stacks of intrinsic Josephson junctions (IJJs) in extremely anisotropic high-temperature superconductors such as Bi2Sr2CaCu2O8 are a promising compact solid-state source of coherent radiation in the 'terahertz gap' range. At present, no such sources exist in the range from approximately 0.5 THz to 1.3 terahertz, and this region is of particular interest for many applications in science, medicine, and high-bandwidth communications, as well as in security and defense. In order to generate technologically useful levels of power from these stacks, it is necessary to obtain efficient phase-synchronized emission from the largest possible number of individual Josephson junctions. Following this approach, I have recently increased the coherent power output from this type of device to 0.6 milliwatts at 0.51 THz, which is approximately the power level required for practical real-time imaging applications.

High temperature superconductors which contain stacked IJJs - namely the bismuth- and thallium-based cuprate compounds - offer a further unique property: they are expected to allow the propagation of Josephson Plasma Waves. Theorists predict that the copper-oxide planes of these HTS cuprates act as natural superconducting waveguides which can channel energy through the structures of these crystals at microwave and terahertz frequencies. My experiments in Bi2Sr2CaCu2O8 provide strong indirect evidence of this phenomenon. The efficient propagation and non-linearity of Josephson Plasma Waves offers the possibility of novel devices for THz frequency signal processing, such as ridge waveguides, mixers, and modulators/demodulators. Such devices would be extremely valuable for ultra-high bandwidth telecommunications for both wired and wireless applications.

Realizing the full technological potential of complex oxide materials such as these will require advances in thin film growth technology beyond what is presently available, and I am currently developing techniques for growth of thin films with the quality of a single crystal.

Publications

Journal Articles:

Triode for Magnetic Flux Quanta
V. K. Vlasko-Vlasov, F. Colauto, T. Benseman, D. Rosenmann, & W.-K. Kwok
Nature Scientific Reports 6, 36847 (2016).

Current filamentation in large Bi2Sr2CaCu2O8 mesa devices observed via luminescent and scanning laser thermal microscopy
T. M. Benseman, A. E. Koshelev, V. Vlasko-Vlasov, Y. Hao, W.-K. Kwok, U. Welp, C. Keiser, B. Gross, M. Lange, D. Kölle, R. Kleiner, H. Minami, C. Watanabe, & K. Kadowaki
Physical Review Applied, 3, 044017 (2015).

Antiferromagnetic and nematic phase transitions in BaFe2(As1-xPx)2 studied by AC micro-calorimetry and SQUID magnetometry
X. Luo, V. Stanev, B. Shen, L. Fang, X. S. Ling, R. Osborn, S. Rosenkranz, T. M. Benseman, R. N. S. Divan, W.-K. Kwok, & U. Welp
Physical Review B, 91, 094512 (2015).
 
Powerful terahertz emission from Bi2Sr2CaCu2O8 mesa arrays
T. M. Benseman, K. E. Gray, A. E. Koshelev, W.-K. Kwok, U. Welp, H. Minami, K. Kadowaki, & T. Yamamoto
Applied Physics Letters 103, 022602 (2013).
 
The ac Josephson relation and inhomogeneous temperature distributions in large Bi2Sr2CaCu2O8 mesas for THz emission
T. M. Benseman, A. E. Koshelev, W.-K. Kwok, U. Welp, K. Kadowaki, J. R. Cooper, & G. Balakrishnan
Superconductor Science and Technology 26, 085016 (2013).
 
Jamming of superconducting vortices in a funnel structure
V. Vlasko-Vlasov, T. M.  Benseman, U. Welp, & W.-K. Kwok
Superconductor Science and Technology 26, 075023 (2013).
 
Direct imaging of hot spot in Bi2Sr2CaCu2O8 mesa terahertz sources
T. M. Benseman, K. E. Gray, A. E. Koshelev, W.-K. Kwok, U. Welp, V. Vlasko-Vlasov, & K. Kadowaki
Journal of Applied Physics 113, 133902 (2013).
 
Tunable terahertz emission from Bi2Sr2CaCu2O8 mesa devices
T. M. Benseman, A. E. Koshelev, K. E. Gray, W.-K. Kwok, U. Welp, K. Kadowaki, M. Tachiki, & T. Yamamoto
Physical Review B 84, 064523 (2011).
 
Valency and spin states of substituent cations in Bi2Sr2CaCu2O8
T. M. Benseman, J. R. Cooper, C. L. Zentile, L. Lemberger, & G. Balakrishnan
Physical Review B 84, 144503 (2011).
 
Evidence for Dirac nodes from quantum oscillations in SrFe2As2
M. Sutherland, D. J. Hills, B. S. Tan, M. M. Altarawneh, N. Harrison, J. Gillett, E. C. T. O’Farrell, T. M. Benseman, I. Kokanovic, P. Syers, J. R. Cooper, & S. E. Sebastian
Physical Review B (Rapid Comm.) 84, 180506(R) (2011).
 
A detailed de Haas–van Alphen effect study of the overdoped cuprate Tl2Ba2CuO6
P. M. C. Rourke, A. F. Bangura, T. M. Benseman, M. Matusiak, J. R. Cooper, A. Carrington, & N. E. Hussey
New Journal of Physics 12, 105009 (2010).
 
Fermi surface and electronic homogeneity of the overdoped cuprate superconductor Tl­2Ba2CuO6 as revealed by quantum oscillations
A. F. Bangura, P. M. C. Rourke, T. M. Benseman, M. Matusiak, J. R. Cooper, N. E. Hussey, & A. Carrington
Physical Review B (Rapid Comm.) 82, 140501(R) (2010).
 
Increased Tc in Electrolyte-Gated Cuprates
A. S. Dhoot, S. C. Wimbush, T. M. Benseman, J. L. MacManus-Driscoll, J. R. Cooper, & R. H. Friend
Advanced Materials 22, 2529–2533 (2010).
 
In-plane oxygen diffusion in single crystals of Bi2Sr2CaCu2O8
T. M. Benseman, J. R. Cooper, & G. Balakrishnan
Physica C 468, 81-87 (2008).
 
The phase diagram of high-Tc superconductors
J. L. Tallon, T. M. Benseman, G. V. M. Williams, & J. W. Loram
Physica C 415, 9-14 (2004).

Invited Conference Presentations:

Terahertz radiation from Bi2Sr2CaCu2O8 interlayer Josephson junctions: Progress and future strategies
T. M. Benseman, A. E. Koshelev, V. Vlasko-Vlasov, Y. Hao, U. Welp, W.-K. Kwok, B. Gross, M. Lange, D. Koelle, R. Kleiner, & K. Kadowaki
Presented at 14th International Workshop on High-Frequency Superconducting Electronics, Bjorkliden, Sweden, April 2016.

Terahertz radiation from Bi2Sr2CaCu2O8 interlayer Josephson junctions: Progress and future applications
T. M. Benseman, A. E. Koshelev, V. Vlasko-Vlasov, Y. Hao, U. Welp, W.-K. Kwok, B. Gross, M. Lange, D. Koelle, R. Kleiner, & K. Kadowaki
Presented at Vortex workshop 2015, El Escorial, Spain, May 2015.

Terahertz radiation from Bi2Sr2CaCu2O8 interlayer Josephson junctions: Progress and future strategies
T. M. Benseman, A. E. Koshelev, V. Vlasko-Vlasov, Y. Hao, U. Welp, W.-K. Kwok, B. Gross, M. Lange, D. Koelle, R. Kleiner, & K. Kadowaki
Presented at AMN-7 conference (Advanced Materials & Nanotechnology), Nelson, New Zealand, February 2015.

Powerful coherent terahertz emission from Bi2Sr2CaCu2O8 mesa array
T. M. Benseman, U. Welp, A. E. Koshelev, K. E. Gray, W.-K. Kwok, H. Minami, K. Kadowaki, & T. Yamamoto
Presented at PLASMA 2012 Conference, Izmir, Turkey, June 2012.