Presentation Information
[10p-E201-18]Development of a Multi-Color Spectroscopic Near-Field Microscope and Its Application to Lattice Dynamics Measurements
〇KuanTing Lin1, Zheyuan Zhou1, Megumi Yamamoto1, Ryoko Sakuma1, Qianchun Weng2, Yusuke Kajihara1 (1.Univ. Tokyo, 2.CAS)
Keywords:
Near-field spectroscopy,Infrared detector,Nanoscale thermal radiation
Thermally excited evanescent waves from spontaneous lattice vibrations carry intrinsic localized thermal and dielectric information. We previously developed a passive spectroscopic scattering-type scanning near-field optical microscope (s-SNOM) combining a narrow-band detector with a diffraction grating. However, establishing a multi-wavelength spectroscopic system is indispensable to comprehensively understand localized thermal behaviors and complex lattice dynamics across a broader spectral range.
Here, we report an advanced spectroscopic near-field microscope equipped with a newly implemented, highly sensitive multi-color charge-sensitive infrared phototransistor (CSIP) as the detector. This cryogenic system integrates the multi-color CSIP with a customized blazed diffraction grating to disperse and detect weak thermal signals scattered by a height-modulated AFM probe tip. By scanning the grating angle, the instrument response was characterized via the far-field spectrum of a Au reference, successfully resolving three distinct detection channels of the multi-color CSIP at 9.1, 11.8, and 13.9 μm.
Crucially, spectroscopic measurements on SiC successfully resolved the localized thermal near-field spectrum. The near-field profile captured a pronounced signal enhancement within the Reststrahlen band of SiC, closely associated with surface phonon polariton (SPhP) resonance. Conversely, the far-field spectrum exhibited a distinct dip within the Reststrahlen band due to the total reflection characteristics of SiC; notably, compared to the Au baseline, its signal was prominently suppressed at the 11.8 μm peak. This multi-color CSIP-implemented passive s-SNOM provides exceptional sensitivity and wavelength selectivity, offering a powerful platform for exploring nanoscale thermal radiation phenomena.
Here, we report an advanced spectroscopic near-field microscope equipped with a newly implemented, highly sensitive multi-color charge-sensitive infrared phototransistor (CSIP) as the detector. This cryogenic system integrates the multi-color CSIP with a customized blazed diffraction grating to disperse and detect weak thermal signals scattered by a height-modulated AFM probe tip. By scanning the grating angle, the instrument response was characterized via the far-field spectrum of a Au reference, successfully resolving three distinct detection channels of the multi-color CSIP at 9.1, 11.8, and 13.9 μm.
Crucially, spectroscopic measurements on SiC successfully resolved the localized thermal near-field spectrum. The near-field profile captured a pronounced signal enhancement within the Reststrahlen band of SiC, closely associated with surface phonon polariton (SPhP) resonance. Conversely, the far-field spectrum exhibited a distinct dip within the Reststrahlen band due to the total reflection characteristics of SiC; notably, compared to the Au baseline, its signal was prominently suppressed at the 11.8 μm peak. This multi-color CSIP-implemented passive s-SNOM provides exceptional sensitivity and wavelength selectivity, offering a powerful platform for exploring nanoscale thermal radiation phenomena.