Imbuia Beamline

IMBUIA (Infrared Multiscale Beamline for Ultra-resolved Imaging Applications) is a beamline dedicated to experiments in micro and nano-infrared spectroscopy in the medium IR range. These experiments allow for compositional analysis of virtually any material and are essential for the research in new materials, with emphasis on biological and synthetic materials.

Infrared spectroscopy (FTIR) is one of the most established techniques for the analysis of organic and inorganic compounds. This energy range of the electromagnetic spectrum contains the energy levels associated with the vibrations and molecular rotations. Such vibrational and rotational modes are particular signatures of functional groups of the molecules. However, many properties of materials and functions are defined by distinct phases (structural or chemical) in areas and interfaces at the scale of nanometers and few microns. In this context, tools for the analysis of materials via FTIR microscopy and nanoscopy are essential for cutting-edge research of new materials as well as for the understanding of natural materials.

IMBUIA is dedicated to experiments of micro and nano-FTIR in the mid-IR range. For this, its optics collects bending radiation generated by one of the dipoles of the Sirius accelerator, which will be divided into two experimental stations. The first experimental station (IMBUIA-micro) is equipped with an infrared micro-spectrometer to operate with a probe within the diffraction limit, with typical spatial resolution of 3-10 micrometers. The second station (IMBUIA-nano) is equipped with a near-field microscope that can reach spatial resolution beyond the diffraction limit, typically 25 nm.

## CONTACT & STAFF

Coordination: Raul de O. Freitas
Tel.: +55 19 3517 5060
E-mail: raul.freitas@lnls.br

## EXPERIMENTAL TECHNIQUES

In the two experimental stations of the IMBUIA beamline, the following techniques will be available:

### $\rm μ$-FTIR in transmission and reflection modes and ATR (Attenuated Total Reflectance)

μ-FTIR is an experiment mainly performed in synchrotrons. The brillance in the μ-FTIR experiments can be up to 1000 times greater than a conventional FTIR experiment (thermal sources), providing the highest signal-to-noise available in vibrational analysis techniques in the medium IR range. In this energy range, there are key molecular vibrational modes of the functional groups of organic compounds. Thus, for example, the technique is especially attractive in biochemical research of isolated animal cells [1, 2].

[1] E. Giorgini, G. Gioacchini, S. Sabbatini, C. Conti, L. Vaccari, a Borini, O. Carnevali, e G. Tosi, “Vibrational characterization ouriere gametes: a comparative study.”, Analyst, 139, p. 5049–60 (2014).

[2] M. J. Hackett, F. Borondics, D. Brown, C. Hirschmugl, S. E. Smith, P. G. Paterson, H. Nichol, I. J. Pickering, e G. N. George, “Subcellular biochemical investigation of purkinje neurons using synchrotron radiation ourier transform infrared spectroscopic imaging with a focal plane array detector”, ACS Chem. Neurosci., 4, p. 1071–1080 (2013).

### Nano-FTIR and spectral imaging via syncrotron s-SNOM

Nano-FTIR is one of the most advanced techniques for the chemical analysis of materials at the nanoscale. It is based on the combination of the near-field optical scanning microscope (s-SNOM) experiment with a broadband IR beam. Like the FTIR, the nano-FTIR uses an interferometer for the demultiplexing of the broadband response, however, the interaction of the beam is performed via the interaction of a nano-antenna with the surface of the sample. The result is the possibility of FTIR in areas with a few tens of nanometers. The use of synchrotron radiation with s-SNOM has allowed the study of several nanometric materials such as nanostructured polymers [3], biological nanofilms [4], two-dimensional metamaterials based on graphene [5] and dichalcogenides [6]. With the high IR flow and excellent stability delivered by the new Sirius accelerator, the IMBUIA nano-FTIR bemline will be one of the few stations in the world to obtain hyper-spectral IR images with nanometric resolution as well as allow the realization of vibrational spectroscopy of clusters with few molecules.

[3] B. Pollard, F. C. B. Maia, M. B. Raschke, e R. O. Freitas, “Infrared Vibrational Nanospectroscopy by Self-Referenced Interferometry.”, Nano Lett., 16, p. 55–61 (2016).

[4] H. A. Bechtel, E. A. Muller, R. L. Olmon, M. C. Martin, e M. B. Raschke, “Ultrabroadband infrared nanospectroscopic imaging”, Proc. Natl. Acad. Sci., 111, p. 7191–7196 (2014).

[5] I. D. Barcelos, A. R. Cadore, L. C. Campos, A. Malachias, K. Watanabe, T. Taniguchi, F. Barbosa Maia, R. D. O. Freitas, C. Deneke, F. C. B. Maia, R. D. O. Freitas, e C. Deneke, “Graphene/h-BN plasmon–phonon coupling and plasmon delocalization observed by infrared nano-spectroscopy”, Nanoscale, 7, p. 11620–11625 (2015).

[6] P. Patoka, G. Ulrich, A. E. Nguyen, L. Bartels, P. A. Dowben, V. Turkowski, T. S. Rahman, P. Hermann, B. Kästner, G. Ulm, e E. Rühl, “Nanoscale plasmonic phenomena in CVD-grown MoS 2 monolayer revealed by ultra-broadband synchrotron radiation based nano-FTIR spectroscopy and near-field microscopy”, Opt. Express, 24, p. 1154–1164 (2016).

## LAYOUT & OPTICAL ELEMENTS

Element Type Position (m) Description
SOURCE Bending magnet radiation Dipole radiation extracted from a B2 dipole (0,57 T)
M1 Flat mirror 90° 1.20 Flat mirror with Glidcoop substrate and Au reflective surface
W1 Diamond window 1.62 UHV CVD diamond window
M2 Flat mirror 90° 3.75 Au flat mirror
M3 Flat mirror 90° 4.04 Au flat mirror
M4 Parabolic mirror 4.12 Au parabolic mirror for collimation of the beam for the IMBUIA-micro station
W2 KRS5 window 4.93 Optical and UHV KRS5 window
M5 Elliptical mirror 5.20 Au elliptical mirror for focusing (secondary source)
M6 Parabolic mirror 5.89 Au parabolic mirror for collimation of the beam for the IMBUIA-nano station
W3 KRS5 window 14.20 Optical and UHV KRS5 window

## PARAMETERS

Parameter Value Condition
Energy Range 550 – 3500 cm-1 nano and micro-FTIR
Energy Resolution (ΔE/E) 0.1 cm−1 micro-FTIR
Energy Resolution (ΔE/E) 3 cm−1  nano-FTIR
Energy Scan Fourier transform
Beam Size ~5 x 5 μm @ 1000 cm-1 micro-FTIR
Beam Size 25 x 25 nm nano-FTIR
Beam Divergence <1 mrad Inside the experimental stations