The next CU Phonon Club seminar of the semester will be held this Wednesday, April 26th @12pm in JILA X317. Please join us for a great talk, interesting discussion, and FREE FOOD (empanadas)! Hope to see you there! Additionally, if anyone is interested in being involved in the organization of CU Phonon Club, please email: emma.nelson-1@colorado.edu.
Wednesday, April 26th @12pm in JILA X317
Prof. Markus B. Raschke
Department of Physics and JILA, CU Boulder
http://nano-optics.colorado.edu
Thermal nano-physics: near-field radiation, optical forces, and chemical nano-imaging
One of the most universal physical processes shared by all matter at finite temperature is the emission of thermal radiation. Its experimental characterization and theoretical description was a cornerstone in the development of modern physics with the groundbreaking contributions from Gustav Kirchhoff and Max Planck to far-field blackbody radiation. With its origin in thermally driven fluctuations of the charge carriers, thermal radiation reflects the resonant and non-resonant quantum properties of any material. Associated with the elementary thermal fluctuations are fundamentally distinct spectral, spatial, resonant, and coherence properties of the evanescent thermal near-field that give rise to qualitatively new from thermal transport to quantum dynamic properties on the nanoscale. I will discuss the basic theoretical models of the thermal near-field based on fluctuation-dissipation theory, and in terms of the electromagnetic local density of states (EM-LDOS). I will then present our recent work on the optical and spectroscopic characterization of spectral distribution and coherence of evanescent thermal fields [1-4] based on scattering scanning near-field microscopy. I will introduce the use of the derived technique of thermal infrared near-field spectroscopy (TINS) for broadband chemical nano-spectroscopic imaging, where the thermally driven vibrational optical dipoles provide their own intrinsic light source [5]. I will extend to new opportunities of the control of optical gradient forces as a basis for new forms of nano-opto-mechanics and photo-induced force microscopy [6-7], and photothermal engineering based on graphene [8]. I will conclude with an outlook on the possibility of intrinsic and extrinsic resonant manipulation of optical forces, control of nano-scale radiative heat transfer with hybrid metamaterials, and novel opportunities for quantum opto-mechanics and cavity QED for quantum information processing.
References:
[1] R. L. Olmon and M. B. Raschke, “Antenna-load interactions at optical frequencies: impedance matching to quantum systems” Nanotechnology 23, 444001 (2012).
[2] A. C. Jones and M. B. Raschke, “Thermal near-field infrared spectroscopy” Nano Letters 12, 1475 (2012).
[3] A. C. Jones, H. U. Yang, B. T. O’Callahan, and M. B. Raschke, “Thermal near-field: coherence, spectroscopy, heat-transfer, and optical forces” Prog. Surf. Sci. 88, 349 (2013).
[4] B. T. O’Callahan, W. E. Lewis, A. C. Jones, and M. B. Raschke, “Spectral frustration and spatial coherence in thermal near-field spectroscopy” Phys. Rev. B 89, 245446 (2014).
[5] M. B. Raschke, “Infrared Imaging Using Thermal Radiation from a Scanning Probe Tip”, patent number US 7,977,636.
[6] H. U. Yang and M. B. Raschke, “Resonant optical gradient force interaction for nano-imaging and -spectroscopy ” New J. Phys.. 18, 053042 (2016).
[7] B. T. O’Callahan, J. Yan, F. Menges, E. A. Muller, and M. B. Raschke, “Photoinduced tip-sample forces for chemical nano-imaging and -spectroscopy” Nano Letters 18, 5499 (2018).
[8] H. U. Yang, F. Menges, S. Berweger, A. Roy, O. Khatib, and M. B. Raschke, “Thermal nano-lensing through graphene surface plasmon interferometry” (submitted).