Source: BMG Labtech
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Time-Resolved Spectroscopy: Methods and Applications

Introduction

Time-resolved spectroscopy, also known as ultrafast spectroscopy, encompasses various techniques for studying dynamic processes in materials on timescales ranging from seconds to femtoseconds. This article explores different methods used in time-resolved spectroscopy and their applications.

Transient Absorption Spectroscopy

Transient absorption spectroscopy, based on pump-probe measurements, involves exciting a sample with a pump pulse followed by a probe pulse with a variable time delay. The dependence of absorbance or transmittance on the time delay provides insights into the system’s temporal evolution post-excitation.

Fluorescence Decay Measurements

Fluorescence decay measurements are utilized to determine the lifetime of excited energy levels. For longer timescales, photodiodes can directly measure fluorescence decay, while faster processes require pump-probe techniques for accurate measurements.

Coherent Time-Resolved Methods

Coherent time-resolved spectroscopy involves methods where phase values play a crucial role. Quantum beat spectroscopy and photon echoes are examples of coherent techniques used to study molecular dynamics and dephasing processes.

Attosecond Pulse Spectroscopy

Attosecond pulses, generated using high harmonic generation, offer ultra-high temporal resolution for spectroscopic studies. These pulses are used in various methods, including transient absorption spectroscopy and electron spectroscopy, for detailed investigations.

Terahertz Spectroscopy

Terahertz spectroscopy includes time-resolved methods for recording terahertz waveforms using optical sampling techniques. By analyzing terahertz absorption spectra, valuable information about materials can be obtained.

Cavity Ring-down Spectroscopy

Cavity ring-down spectroscopy is employed for sensitive absorption measurements by analyzing the decay time of light in an optical resonator. This method is particularly useful for determining weak absorption in gases with high precision.

Conclusion

Time-resolved spectroscopy techniques play a crucial role in studying dynamic processes in materials at the molecular level. By employing advanced laser sources and sophisticated measurement setups, researchers can gain valuable insights into ultrafast phenomena with high temporal resolution.

Source: LIGHT CONVERSION
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