BESSY II's Infrared Beamline Upgrade Enhances Nanoscale Spectroscopy


A recent study discusses the recent upgrades to the infrared (IR) beamline at BESSY II storage ring, which has helped it improve its results when conducting IR microscopy.

In a recent advancement reported in the Journal of Synchrotron Radiation, lead author Alexander Veber from Humboldt-Universität in Berlin details the significant upgrade to the infrared (IR) beamline at BESSY II storage ring, expanding its capabilities in IR microscopy (1).

BESSY II, which stands for the Berliner Elektronenspeicherring-Gesellschaft fur Synchrotronstrahlung m. b. H., is a research establishment in the Adlershof district of Berlin. It is known for its operation of one of Germany’s synchrotron radiation facilities (2). The storage ring at BESSY II has an important function: it provides fifty-two ultrabright photon beamlines capable of operation from the Terahertz region to hard X-rays (0.0006 eV to 40000 eV), depending on the energy source used, with complete control of the radiation and energy range (2). BESSY II is designed as a space and time microscope, meaning that it could measure femtosecond time and picometer spatial resolutions (2).

Because of its numerous capabilities and functionalities, BESSY II is an important research station to the scientific community. As a result, technical upgrades in response to scientific innovations is essential for BESSY II to remain useful to scientists conducting important research. In this study, Veber and the team review the latest upgrades to BESSY II and highlight the significance of these updates.

Panoramic view at the berlin city center at sunset | Image Credit: © frank peters -

Panoramic view at the berlin city center at sunset | Image Credit: © frank peters -

The research team concentrated their paper on the upgraded IR beamline, named IRIS, that BESSY II now contains. IRIS now boasts four endstations: macro-, single-shot time-resolved, micro-, and nano-spectroscopy. The basic IRIS microscope beamline system currently operates over the spectral range from 2 to 10,000 cm-1. This beamline enhancement enables improved characterization of molecules and materials at various length scales and temporal resolutions (1).

Out of the four endstations BESSY II contains, the nano-spectroscopy endstation is the most important one. This endstation in particular is important because it features a scattering-type scanning near-field optical microscope (s-SNOM) (1). This advanced microscope allows for unprecedented imaging and spectroscopy with a spatial resolution of less than 30 nm (1). By coupling the s-SNOM with the beamline, researchers can collect IR spectra from an effective volume of less than 30 nm × 30 nm × 12 nm (1).

One of the notable demonstrations of the upgraded beamline's capabilities is showcased through the investigation of cellulose microfibrils. These microfibrils serve as nanoscopic objects with a hierarchical structure, offering a challenging yet insightful subject for analysis (1). Through the utilization of s-SNOM, the research team was able to image and spectroscopically examine these structures with unprecedented detail.

Furthermore, Veber and the team highlighted the broader improvements across all endstations. The upgrade facilitates a higher imaging rate utilizing a focal plane array (FPA) detector for diffraction-limited IR microscopy (1). Moreover, the spectral range of diffraction-limited experiments has been extended into the far-infrared (far-IR) region, enhancing the overall imaging and spectroscopy capabilities of the beamline.

Importantly, all four endstations are now accessible to both national and international user groups, underlining the facility's commitment to fostering collaborative research endeavors (1). Additionally, the team emphasized in their study the ongoing efforts to further optimize the beamline's performance, ensuring that state-of-the-art IR spectroscopy techniques remain readily available to researchers (1).

The upgrade to BESSY II is indicative of the technological advancements constantly happening in the field. BESSY II is designed to meet the current and future needs of researchers. Thanks to these new endstations, BESSY II is more equipped to handle the research needs of the scientific community, allowing them to dive deeper into the nanoscale realm of molecular and material characterization.


(1) Veber, A.; Puskar, L.; Kneipp, J.; Schade, U. Infrared Spectroscopy Across Scales in Length and Time at BESSY II. J. Synch. Rad. 2024, 31 (3), 613–621. DOI: 10.1107/S1600577524002753

(2) Helmholtz Zentrum Berlin, BESSY II – An Ultimate Space and Time Microscope. Available at: (accessed 2024-05-01).

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