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SUMMARY:Towards a low temperature terahertz near-field microscope - Dr. Ro
 bert Wallis\,  Department of Physics\, University of Cambridge\, UK
DTSTART:20171129T141500Z
DTEND:20171129T150000Z
UID:TALK96397@talks.cam.ac.uk
CONTACT:Dr Kaveh Delfanazari
DESCRIPTION:Research utilising the terahertz spectral region (0.1 – 10 T
 Hz\, 3000 – 30 µm\, 0.4 – 40 meV) is both diverse and rapidly advanci
 ng\, with applications in spectroscopy\, astronomy\, security imaging\, an
 d pharmaceuticals analysis. This frequency range is of fundamental interes
 t\, corresponding to low energy electronic excitations and vibrational mod
 es in solids\, as well as vibrational and rotational transitions in molecu
 les. However\, the ability to investigate the THz physics of samples at cr
 yogenic temperatures (4 K and below) has to date been hampered by a lack o
 f suitable systems capable of addressing the considerable optical\, mechan
 ical and thermal challenges involved. \nThis talk will outline work toward
 s the development of a near-field nanoscopy system capable of imaging semi
 conductor samples at THz energies and at temperatures of 4 K and below\, w
 ith a spatial resolution better than 100 nm (~λ/1000)\, whilst simultaneo
 usly obtaining topographic information. To achieve this aim\, research int
 o two requisite areas will be discussed - waveguided radiation delivery fo
 r low temperature cryostats\, along with the demonstration of a room tempe
 rature THz near-field microscope utilising a quantum cascade laser as both
  source and detector. Finally\, some future research directions resulting 
 from such a technology will be discussed\, including a selection of the we
 alth of semiconductor systems to be studied\, such as single photon detect
 ors and quantum dot electron pumps. 
LOCATION:Mott Seminar Room (Mott Building Room 531)\, Cavendish Laboratory
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