Open hardware microsecond dispersive transient absorption spectrometer for linear optical response.

Area of Science:

• Spectroscopy
• Physical Chemistry
• Open Hardware Development

Background:

• Transient absorption spectroscopy (TAS) is crucial for studying ultrafast chemical dynamics.
• Existing TAS instruments can be expensive and complex, limiting accessibility.
• There is a need for cost-effective, open-source instrumentation for TAS.

Purpose of the Study:

• To present an open hardware design for a microsecond-resolution transient absorption spectrometer.
• To enable the study of both low and high quantum yield photoreactions.
• To provide a sensitive and accurate tool for analyzing chemical dynamics.

Main Methods:

• Developed an instrument combining xenon lamp excitation flashes (230 ns pulse) and LED stroboscopic probing.
• Utilized an inexpensive CCD sensor for sensitive detection (0.15 mOD resolution).
• Detailed the electronics, optics, timing, and spectrometer modifications for signal referencing.

Main Results:

• Achieved microsecond time resolution across the 380-750 nm visible spectrum.
• Demonstrated sensitivity to resolve 0.15 mOD differences with 1000 measurements at 20 Hz.
• Successfully characterized the instrument using microsecond TAS of Congo red dye, a low quantum yield photoreaction.

Conclusions:

• The presented open hardware TAS is a cost-effective and accessible tool for chemical dynamics research.
• The instrument's design allows for accurate global analysis of photoinduced reactions.
• Open hardware approach facilitates wider adoption and further development in spectroscopy.