Kev sim cov hauv paus ntsiab lus ntawm infrared passive ze-field microscopy (SNoiM) thiab nws cov ntawv thov
Near-field radiation at the surface of an object is difficult to detect due to its swift-wave nature (i.e., the intensity decreases sharply as it moves away from the surface of the object). In SNoiM, this problem is effectively solved using the scanning probe technique. As shown in Fig. 1(b), when the nanoprobe is not introduced (or the probe is far away from the object surface), the near-field snappy waves near the surface of the object cannot be detected, and the microscope operates in the conventional infrared thermography mode, which obtains only the far-field radiated signals.The key of the SNoiM technique is to bring the probe close to the near-surface of the sample (e.g., within 10 nm) so that the near-field snappy waves can be effectively scattered by the tip of the probe. In this detection mode, both near-field and far-field components are present in the sample signal acquired by the probe. Therefore, by controlling the probe-to-surface spacing h, a mixed near-field and far-field signal (h < 100 nm, called near-field mode) or a single far-field signal (h >>100 nm lossis tshem tawm ntawm kev sojntsuam, hu ua far-field mode) tuaj yeem tau txais. Thaum kawg, cov ntaub ntawv nyob ze ntawm qhov khoom tuaj yeem muab rho tawm los ntawm qhov chaw deb tom qab siv qhov ntsuas qhov siab qhov ntsuas thiab cov txheej txheem demodulation.
Cov cim ze ze ntawm qhov tawg los ntawm kev sojntsuam yog thawj zaug sau los ntawm cov lej siab aperture infrared lub hom phiaj lens. Txawm li cas los xij, qhov deb-tsav hluav taws xob teeb liab los ntawm ib puag ncig, DUT thiab cov cuab yeej nws tus kheej tsis tuaj yeem raug tshem tawm hauv cov txheej txheem no, thiab lawv tau sau nrog cov cim ze ze ntawm lub hom phiaj infrared, uas ua rau muaj qhov tsis muaj zog nyob ze ntawm thaj chaw. lub DUT raug rhuav tshem los ntawm cov hluav taws xob loj nyob deb. Txhawm rau txo qis cov cim qhia txog keeb kwm yav dhau los, cov kws tshawb fawb tau tsim lub confocal aperture nrog aperture me me (~ 100 μm) saum lub hom phiaj infrared lens, uas txo qhov chaw sau thiab cuam tshuam cov teeb liab hluav taws xob tom qab. Txawm li cas los xij, txawm tias qhov no, nws nyuaj rau txiav txim siab seb puas muaj lub ntsuas hluav taws xob txaus infrared uas tuaj yeem ntes cov tsis muaj zog nyob ze-tawm cov cim tawg los ntawm nanoprobes. Txog rau qhov kawg no, peb pab neeg tau tsim lub tshuab ntsuas hluav taws xob ultra-high rhiab heev kom kov yeej qhov kev cuam tshuam no.
Ntawm lawv, lub cylindrical kab noj hniav yog ib tug cryogenic Dewar, uas yog tus kheej-tsim ultra-siab rhiab heev infrared detector (CSIP) thiab ib co low-temperature optical Cheebtsam; lub thawv dawb qhia tau hais tias qhov ntsuas qhov nkhaus ntawm lub tshuab hluav taws xob atomic force microscope (AFM), lub hom phiaj sau infrared thiab cov qauv theem hauv cheeb tsam sib sau ua ke hauv chav kuaj. Lub spatial daws teeb meem ntawm IR nyob ze-tsav duab tsis txwv los ntawm kev sojntsuam wavelength, tab sis txiav txim siab los ntawm qhov ntsuas qhov loj me. Los ntawm txoj kev electrochemical etching, hlau (tungsten) nanoprobes nrog zoo heev morphology tuaj yeem npaj tau, nyob rau hauv uas lub taub taub yuav me me li 100 nm lossis tsawg dua.
