The University of Tokyo
Research
Passive THz near-field microscopy 2009~
| ○Motivation Most optical measurements are based on "active" method, in which an external light source illuminates an object and then transmitted, reflected, or scattered light is detected. They just probe "optical response" of the light. We believe probing spontaneous emission from samples is much more interesting. Actually a sample itself radiates photons due to moleculer motion, lattice phonon, etc., whose spectrum lie in THz region (wavelength: 10 μm-1 mm). We intend to "passively" detect the photons without any external illumination. The objective of this study is "probing spontaneous emission from a sample itself in nanoscale". General thermography and astronomical telescope are examples of passive measurement. However they just probe statistically-averaged information because of the lack of sensitivity and spatial resolution. Our new passive near-field microscopy technique has a large potential to visualizey local bio-protein motion, local temperature distribution during chemical reaction, etc. ○Method To achieve passive microscopy in nanoscale, 1) ultra-sensitive THz detector, and 2) nanoscale spatial resolution are strongly required．In this study, we utilize the most sensitive detector, named CSIP (Charge Sensitive Infrared Phototransistor), invented at Komiyama group (Univ. Tokyo), and also introduce scattering-type near-field microscopy technique to solve these two difficulties. ○Situation We have developed a passive THz near-field microscope with a CSIP and have succeeded in probing thermal evanescent waves with 60 nm resolution with 14.5 μm CSIP. As an example of applications, we demonstrated "nano-thermometry", which probes local temperature distribution with nanoscale resolution. Now we are improving the specifications and exproring the potentioal of the microscope in various scientific and engineering field. ○References [Detector] S. Komiyama, IEEE J. Selected Topics Quant. Electr., 17, 54 (2011). [Microscope] Y. Kajihara et al., Opt. Exp., 19, 7695 (2011). Y. Kajihara et al., Rev. Sci. Inst., 81, 033706 (2010). |
 active and passive microscopy |
 passive near-field detection |
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 passive near-field image (60 nm resolution) |
Polymer evaluation with IR/THz measurement 2012～
| IR and THz waves are compatible with polymer products. We are now developing more convenient and reliable techniques for polymer evaluation with IR/THz measurements. |
Jointing manufacturing (metal-polymer) 2013～
| Jointing differnt materilas is a key technology for weight saving. We focus on new metal-polymer jointing method with nano-structure surface, and proceed the optimization and interpret the jointing mechanism with our special mold. |
