High-End FTIR Applications
Using VERTEX Vacuum Spectrometers

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MIR Photoluminescence (PL)

Amplitude Modulated Step Scan.

Characterization of Ultra-Thin Layers

Highest Sensitivity for Mono-Molecular Layers.

Spectroelectrochemistry with Rapid Scan

Monitoring of Fast Electrochemical Process Without Atmospheric Disturbance.

Further Applications

VERTEX 80v and VERTEX 70v

High-End Research Applications Using VERTEX Series Vacuum Spectrometers.

VerTera THz-Extension for VERTEX 80v

The world's first combined FTIR/cw THz Spectrometer.

UHV FTIR Spectroscopy

VERTEX Vacuum Spectrometers adapted to Customized Ultra-High Vacuum Apparatus.

Step Scan TRS Spectroscopy

VERTEX 80v Provides Highest Accuracy Using Time Resolved Stepwise Data Acquisition.


Photoluminescence (PL) is an important analysis method in material/semiconductor sciences and optoelectronics. In the infrared spectral range the sensitivity of the FTIR technique is significantly higher than for dispersive spectrometers. Bruker has decades of experience offering powerful PL solutions with the FTIR research spectrometers.

For NIR PL the weak atmospheric absorptions of water vapor and CO2 are not a big issue, so vacuum FTIR spectrometers are not necessarily required. In the MIR region two additional challenges occur for PL experiments. First, atmospheric absorption is significantly stronger. Since PL measurements typically mean single channel spectroscopy there is no reference measurement to compensate the main part of atmospheric artifacts. Secondly, the LN2 cooled PL detector is sensitive to the MIR 300 K thermal background radiation, which will mask weak MIR PL signals. On account of this, amplitude modulated step scan must be used to get rid of the disruptive thermal background contribution.

To do so, modulated laser excitation is applied which in turn requires step-scan data acquisition. As a result also the PL signal will be modulated with the known modulation frequency of the excitation laser. Using state of the art dual channel electronics and lock-in techniques the modulated PL signal is then amplified while the constant and unwanted thermal background is suppressed and filtered out. Due to the above two challenges, vacuum spectrometers with dedicated vacuum PL module are highly recommended for MIR PL experiments. Since the entire beam path is under vacuum, atmospheric absorption can be completely eliminated. Furthermore, vacuum spectrometers and especially the VERTEX 80v has the best step scan performance for amplitude modulated experiments to suppress thermal background.

Read Application Note AN 134

Further Information

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