s-SNOM microscope and incidence optics of the IR1 beamline.

OVERVIEW

The IR1 beamline is an endstation dedicated to infrared nanospectroscopy (nano-FTIR) in the range of mid-IR. Its main purpose is the analysis of chemical-optical properties of condensed matter in the nanoscale. In similar fashion to established infrared spectroscopy (FTIR), the nano-FTIR allows for identification and characterization of a chemical compound by means of its vibrational response, however, with nanoscale spatial resolution. Moreover, nano-FTIR is a technique based on near-field optics and, therefore, can be applied to the optical analysis in the sub-diffractional regime of plasmonic and photonic materials.

To overcome the diffraction limit of light, this experimental endstation uses the broadband synchrotron IR beam extracted from the LNLS storage ring as the light source for the experiment Scattering Near-Field Optical Microscopy (s-SNOM). In this experiment a metal coated atomic force microscopy (AFM) tip acts as an antenna for the light confinement at the its apex, creating a new source that no longer depends on the incident light wavelength but it is defined by the shape of the AFM probe, allowing for a spatial resolution of c.a. 25 nm.

The specifications of IR1 beamline of LNLS allows for multidisciplinary studies in Physics, Chemistry and Biology, in particular those studies in which the local chemical information is the central point in the research.

Potential applications are: Opto-electronics and vibrational properties of 2D materials, chemical analysis of sub-micron molecular domains in polymer blends, nano-drugs delivery, single cell chemistry, vibrational analysis of archeological micro-artefacts, new nanostructured materials for energy harvesting and conversion.

EXPERIMENTAL TECHNIQUES

The IR1 beamline is exclusively dedicated to the Scattering Near Field Optical Microscopy technique (s-SNOM) which associates infrared microscopy (μ-FTIR) and atomic force microscopy (AFM). To learn more about the techniques’ limitations and requirements (sample, environment, etc.) contact the beamline coordinator before submitting your proposal.

SCATTERING SCANNING NEAR-FIELD OPTICAL MICROSCOPY (S-SNOM)

scattering Scanning Near-Field Optical Microscopy (s-SNOM) is a nanoscopy technique which combines Atomic Force Microscopy (AFM) and optics for producing a tip-enhanced optical or infrared (IR) probe with spatial resolution beyond the diffraction limit of light. In the case of the IR1 beamline, the broadband synchrotron IR beam is focused on a metallic AFM tip (nano-antenna) generating a broadband source smaller than 40 nm. The interaction of the IR nano-source with the sample surface yields broadband images (scanning mode) or 40 nm pixel point spectrum.

Recent publications:

B. Pollard et al. (2016). Infrared Vibrational Nanospectroscopy by Self-Referenced Interferometry. Nano Letters, vol. 16, 55–61. doi: 10.1021/acs.nanolett.5b02730
I. Barcelos et al. (2015). Graphene/h-BN Plasmon-phonon coupling and plasmon delocalization observed by infrared nano-spectroscopy. Nanoscale, vol.7, 11620–11625. doi: 10.1039/C5NR01056J
T. Moreno et al. (2013). Optical layouts for large infrared beamline opening angles. Journal of Physics: Conference Series, 425(14), 142003. doi:10.1088/1742-6596/425/14/142003

LAYOUT & OPTICAL ELEMENTS

Element	Type	Position [m]	Description
SOURCE	Bending Magnet	0.0	Bending Magnet D03 exit A (4°), 1.67 T, 30 mrad x 80 mrad
M1	Plane, 6 mm slot	2.5	Gold coated, aluminum substrate
M2	Tangential cone-shaped	3.1	Gold coated, aluminum substrate
M3	Tangential cylinder	3.7	Gold coated, aluminum substrate
CVD	Diamond window	7.0	20 mm diameter by 500 $ \mu \rm m$ diamond window by Chemical Vapor Deposition
M4	Tangential cylinder	7.5	Gold coated, aluminum substrate
M5	Tangential cylinder	7.9	Gold coated, aluminum substrate

PARAMETERS

Parameter	Value	Condition
Energy range [ $ \rm cm^{-1}$ ]	3000 - 700	Broadband radiation limited by beamsplitter transmission and detector sensitivity
Energy resolution [ $ \rm cm^{-1}$ ]	Up to 3.3	Limitted by the interferometer travel
Beam size at sample [nm, FWHM]	< 40 nm	Near-field spot defined by the size of the s-SNOM tip
Flux at first optical element [Phot/s/0.1%bw]	$ 2.0 \times 10^{13}$	at 1000 $ \rm cm^{-1}$ (10 $ \mu \rm m$)
AFM scanning stage (maximum travel) [ $ \mu \rm m$ ]	$ \pm$45	-
AFM scanning stage minimum step [nm]	5	-

INSTRUMENTATION

Instrument	Type	Model	Specifications	Manufacturer
s-SNOM	Near-field Optical Microscope	NeaSnom	-	NeaSpec
MCT Detector	Single element Mercury-Cadmium-Telluride (MCT)	KLD-0.1-J1208L	750 $ \rm cm^{-1}$ to 3000 $ \rm cm^{-1}$, 100 $ \mu \rm m$ element size, DC to 1 MHz BW, $ \rm LN_{2}$ cooled	Kolmar Technologies
MCT Detector	Single element MCT	IRA-20-00103	650 $ \rm cm^{-1}$ to 3000 $ \rm cm^{-1}$, 50 $ \mu \rm m$ element size, 500 Hz to 2 MHz BW, $ \rm LN_{2}$ cooled	Infrared Associates Inc.
Si Detector	Single element Silicon detector	PDA36A-EC	350 nm to 1100 nm, 3.6 mm x 3.6 mm element size, DC to 10 MHz BW , air cooled	Thorlabs
InGaAs Detector	Single element Indium-Gallium-Arsenide (InGaAs) detector	PDA10D-EC	PDA10D-EC	Thorlabs
Lock-in amplifier	2 input channels digital lock-in amplifier	HF2LI	DC to 50 MHz, 210 MSa/s, USB 2.0 high-speed, 480 Mbit/s	Zurich Instruments
Visible laser	HeNe laser	HNL150L	15 mW HeNe (633 nm) laser	Thorlabs

CONTROL AND DATA ACQUISITION

Data acquisition is performed directly in the native software of the NeaSnom microscope developed by Neaspec. S-SNOM image files are compatible with the free program Gwyddion (http://gwyddion.net) and point spectra, linescans and spectral images are postprocessed using Mathematica® routines developed by the IR1 team.

HOW TO CITE THIS FACILITY

Users are required to acknowledge the use of LNLS facilities in any publications and to inform the Laboratory about any publications, thesis and other published materials. Users must also cooperate by supplying this information upon request.

Support text for acknowledgements:

This research used resources of the Brazilian Synchrotron Light Laboratory (LNLS), an open national facility operated by the Brazilian Centre for Research in Energy and Materials (CNPEM) for the Brazilian Ministry for Science, Technology, Innovations and Communications (MCTIC). The _ _ _ beamline staff is acknowledged for the assistance during the experiments.

OTHER REFERENCES

Scattering Scanning Near-field Optical Microscopy (s-SNOM)

Keilmann, F. & Hillenbrand, R. Near-field microscopy by elastic light scattering from a tip. Trans. A. Math. Phys. Eng. Sci. 362, 787–805 (2004).
Huth, F., Schnell, M., Wittborn, J., Ocelic, N. & Hillenbrand, R. Infrared-spectroscopic nanoimaging with a thermal source. Mater. 10, 352–6 (2011).
Huth, F. et al. Nano-FTIR absorption spectroscopy of molecular fingerprints at 20 nm spatial resolution. Nano Lett. 12, 3973–8 (2012).
Muller, E. A., Pollard, B. & Raschke, M. B. Infrared Chemical Nano-Imaging: Accessing Structure, Coupling, and Dynamics on Molecular Length Scales. Phys. Chem. Lett. 6, 1275–1284 (2015).

Infrared Spectroscopy Espectroscopia de Infravermelho (FTIR)

Griffiths, P. R. & de Haseth, J. a. Fourier Transform Infrared Spectrometry. Chemical Analysis: A Series of Monographs on Analytical Chemistr and Its Applications (2007). doi:10.1002/047010631X
Smith, Brian C. “Fourier transform infrared spectroscopy.” CRC, Boca Raton, FL(1996).

Atomic Force Microscopy Microscopia de Força Atômica

Eaton, P. & West, P. Atomic Force Microscopy. (Oxford University Press, 2010). doi:10.1093/acprof:oso/9780199570454.001.0001

PUBLICATIONS

Scientific publications produced with data obtained at the facilities of this beamline, and published in journals indexed by the Web of Science, are listed below.

Attention Users: Given the importance of the previous scientific results to the overall proposal evaluation process, users are strongly advised to check and update their publication record both at the SAU Online website and at the CNPEM library database. For the library, updates can be made by sending the full bibliographic data to the CNPEM library (biblioteca@cnpem.br). Publications are included in the database after being checked by the CNPEM librarians and the beamline coordinators.

IR1 XRD2

López, E. O.; Rossi, An.L.; Bernardo, P. L.; Freitas, R. O.; Mello, A.; Rossi, A. M.. Multiscale connections between morphology and chemistry in crystalline, zinc-substituted hydroxyapatite nanofilms designed for biomedical applications, Ceramics International, v. 45, n. 1, p. 793-804, 2019. DOI: 10.1016/j.ceramint.2018.09.246

IR1

Maia, F. C. B.; O’Callahan, B. T. ; Cadore, A. R.; Barcelos, I. D.; Campos, L. C.; Watanabe, K. ; Taniguchi, T.; Deneke, C.; Belyanin, A. ; Raschke, M.; Freitas, R. O.. Anisotropic Flow Control and Gate Modulation of Hybrid Phonon-Polaritons, Nano Letters, v. 19, n. 2, p. 708-719, 2019. DOI: 10.1021/acs.nanolett.8b03732

IR1

Freitas, R. O.; Deneke, C.; Maia, F. C. B.; Medeiros, H. G.; Moreno, T.; Dumas, P.; Petroff, Y. P.; Westfahl Jr., H.. Low-aberration beamline optics for synchrotron infrared nanospectroscopy, Optics Express, v. 26, n. 9, p.11238-11249, 2018. DOI: 10.1364/OE.26.011238

IR1

Colucci, R.; Quadros, M. H.; Feres, F. H. ; Maia, F. C. B.; Vicente, F. S.; Faria, G. C.; Santos, L. F.; Gozzi, G.. Cross-linked PEDOT: PSS as an alternative for low-cost solution-processed electronic devices, Synthetic Metals, v. 241, p. 47-53, 2018. DOI: 10.1016/j.synthmet.2018.04.002

IR1

Barcelos, I. D.; Cadore, A. R.; Alencar, A. B.; Maia, F. C. B.; Mania, E. ; Oliveira, R. F.; Bof Bufon, C. C.; Malachias, A.; Freitas, R. O.; Moreira, R. L.; Chacham, H.. Infrared Fingerprints of Natural 2D Talc and Plasmon-Phonon Coupling in Graphene-Talc Heterostructures, ACS Photonics, v. 5, n. 5, p. 1912-1918, 2018. DOI: 10.1021/acsphotonics.7b01017

IR1

Pereira, L.; Flores-Borges, D. N. A.; Bittencourt, P. R. L. ; Mayer, J. L. S.; Kiyota, E.; Araújo, P.; Jansen, S. ; Freitas, R. O.; Mazzafera, P.. Infrared Nanospectroscopy Reveals the Chemical Nature of Pit Membranes in Water-Conducting Cells of the Plant Xylem, Plant Physiology, v. 177, n. 4, p. 1629-1638, 2018. DOI: 10.1104/pp.18.00138

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