Equipment Vibration spectroscopy
Research in the field of infrared and Raman spectroscopy deals with the development and application of molecular spectroscopic analysis techniques for qualitative and quantitative analysis. The working group "Environment-, Process Analytics and Sensors" under the direction of Univ.Prof. B. Lendl, opens an external URL in a new window focuses on new technological developments, such as infrared quantum cascade laser, optical waveguide (planar waveguides and fibers), standing ultrasound fields for particle manipulation as well as the conception of new software for multimodal and multivariant data analysis. The aim is to develop and apply improved analytical chemical measuring systems by combining new technologies. These novel measuring systems can be used to solve analytical-chemical problems from a wide variety of application areas such as environmental and process analysis, medical diagnostics and the life sciences.
The following measuring devices are available:
The two nanoIR instruments, a nanoIR 1 and the cutting-edge nanoIR 3s, are scanning probe microscopes optimized for optical near-field spectroscopy with photothermal induced resonance (PTIR or AFM-IR) and are coupled two pulsed MIR lasers.
The local optical absorption is measured via the thermal expansion of the sample to achieve a lateral spatial resolution below the diffraction limit (~20 nm). Ultra-high resolution AFM-IR near-field spectra can be directly compared with conventional FTIR transmissions or ATR spectra, thus allowing chemical analysis in the nanometre range.
In addition, the nanoIR systems also provides AFM topography images. In SJEM (Scanning Joule Expansion Mode) local resistance heating in circuits and devices can be quantified.
The WITEC Raman-AFM-SNOM systems core consists of a fibre-coupled Raman microscope with 4 laser lines (488, 532, 633 and 785 nm) and two spectrometers, which are optimised for the visible or near infrared range. A special feature of the instrument is the Atomic Force Microscope (AFM), which can be introduced via the nosepiece for topographic measurements. Thus parts of the samples can be sequentially examined by both AFM and confocal Raman microscopy. With the “TRUE Surface” device the topography of a rough sample can be examined with the result of an imaging Raman analysis even at high magnification, furthermore polarisation-dependent Raman measurements can be performed. The fibre optics allows the system to be modified for inverse Raman microscopic measurements. By means of special AFM cantilevers, which have a small opening at the tip, as well as a single-photon detector, aperture Scanning Nearfield Optical Microscopy (SNOM) can also be performed.
The FTIR imaging systems consists of a FTIR spectrometer (Bruker Tensor 37), which is equipped with an FPA detector with 64x64 pixels, and connected to an infrared microscope (Bruker Hyperion 3000). The Hyperion 3000 is an FTIR microscope that records infrared absorptions spectra of micrometer sized samples. The focal plane array detector (FPA) allows imaging with a high lateral resolution and low measurement times. The Attenuated total reflection lens allows to collect infrared images of samples at an even higher resolution while reducing interferences. It is used to image biological and medical samples, as well as gemstones and works of art. The combination of lateral and spectral information is important for complex analytical problems in these and many other analytical applications.
The Bruker Vertex 70v and Bruker Vertex 80v are high end FTIR spectrometers that have capabilities for liquid, solid and gas spectroscopy beyond those of standard FTIR spectrometers. It is equipped with a step scan and a high resolution extension and allows measurements with a high spectral resolution (0.07 cm-1) in addition to a time resolution (2ns). Furthermore the IR beam may be outcoupled while external light sources are coupled in. They are used for high resolution gas spectroscopy, for high sensitivity spectroscopy of liquids and for time resolved measurements of QCL laser emissions.
The LabRAM HR from Horiba JY is equipped with two laser lines (633 and 532 nm). A variety of lenses allows the measurement of different samples. The spectrometer has been continuously expanded and updated. A new software, a new high-speed detector and an automated x,y,z-table, allows this system to be used for imaging analysis.
Quantum Cascade Lasers (QCLs) are high powered, tunable infrared light sources. We have succesfully applied these novel light sources for liquid and gas spectroscopy. We use five Daylight Solutions External Cavity-QCLs (890-1240 cm-1, 1565-1729 cm-1, 1220-1280 cm-1, Hedgehog 1470-1800 cm-1, 1x MIRcat) as well as several custom made DFB (Alpes Laser) and Ring QCL (Institute of Solid State Electronics, TU Wien).
Through our close cooperation with the Institute of Solid State Electronics (TU Wien) we have gained considerable know-how in the characterisation of QCL light sources.