Ultrafast Coherent Terahertz Spectroscopy in High Magnetic Fields and Directed Energy Flows in Quantum Dot Assemblies

• Authors: S. Crooker , T. Barrick , J. Hollingsworth , V. Klimov
• Languages of publication: EN

Abstracts

EN

We describe the design, construction, and use of fiber-coupled terahertz antennas for performing ultrafast coherent THz spectroscopy directly in the cryogenic bore of high-field magnets. With an aim towards measuring the high-frequency (100 GHz to 2000 GHz) complex conductivity of correlated electron materials in the regime of low temperatures and high magnetic fields, these miniature THz emitters and receivers are demonstrated to work down to 1.5 K and up to 18 T, for eventual use in higher-field magnets. Results from a variety of semiconducting and superconducting samples are presented. This paper also describes a separate effort towards achieving coupling between colloidal semiconductor nanocrystal quantum dots, wherein we realize and study inter-dot communication via resonant (Förster) energy transfer. We present studies of the dynamics of resonant energy transfer in monodisperse and energy gradient (layered) assemblies of CdSe nanocrystal quantum dots. Time- and spectrally-resolved photoluminescence data directly reveal the energy-dependent transfer rate of excitons from smaller to larger dots. Results from layered nanocrystal quantum dot assemblies demonstrate unidirectional energy flows, a first step towards artificial light-harvesting structures. Lastly, time-resolved studies at millikelvin temperatures elucidate the nature of ground-state"dark" excitons in these quantum dots.

Keywords

EN

42.65.Re; 41.20.Jb; 73.21.La; 78.47.+p

Discipline

• 41.20.Jb: Electromagnetic wave propagation; radiowave propagation(for light propagation, see 42.25.Bs; for electromagnetic waves in plasma, see 52.35.Hr; for atmospheric, ionospheric, and magnetospheric propagation, see 92.60.Ta, 94.20.Bb, and 94.30.Tz, respectively; see also 94.05.Pt Wave/wave, wave/particle interactions, in space plasma physics)
• 42.65.Re: Ultrafast processes; optical pulse generation and pulse compression(for ultrafast spectroscopy, see 78.47.J-; for ultrafast magnetization dynamics, see 75.78.Jp)
• 73.21.La: Quantum dots

• Journal: Acta Physica Polonica A
• Year: 2003
• Volume: 104
• Issue: 2
• Pages: 113-122

Dates

published

2003-08

received

2003-05-30

Contributors

author

S. Crooker

• National High Magnetic Field Laboratory, Los Alamos, NM 87545, USA

author

T. Barrick

• National High Magnetic Field Laboratory, Los Alamos, NM 87545, USA

author

J. Hollingsworth

• Chemistry Division, Los Alamos, NM 87545, USA

author

V. Klimov

• Chemistry Division, Los Alamos, NM 87545, USA

References

• 1. P.R. Smith, D.H. Auston, M.C. Nuss, IEEE J. Quantum Electron., QE-24, 255, 1988; C. Fattinger, D. Grischkowsky, Appl. Phys. Lett., 54, 490, 1989
• 2. See, e.g., papers by M.C. Nuss, and by D. Grischkowsky
• 3. S.A. Crooker, Rev. Sci. Instrum., 73, 3258, 2002
• 4. S.A. Crooker, J.A. Hollingsworth, S. Tretiak, V.I. Klimov, Phys. Rev. Lett., 89, 186802, 2002
• 5. S.A. Crooker, T. Barrick, J.A. Hollingsworth, V.I. Klimov, Appl. Phys. Lett., 82, 2793, 2003
• 6. Al.L. Efros, M. Rosen, M. Kuno, M. Nirmal, D.J. Norris, M. Bawendi, Phys. Rev. B, 54, 4843, 1996

Identifiers

DOI

10.12693/APhysPolA.104.113