Tidsupplöst

Tidsupplöst, or time-resolved, describes measurements, signals, or data that distinguish events as a function of time, with sufficient time resolution to track rapid changes. In Swedish scientific usage, the term is used across physics, chemistry, biology, and astronomy to indicate experiments where a property is measured at successive times after an initiating event.

Measurement principle: An event or process is initiated (for example by a laser pulse), and the subsequent evolution is probed at variable delays. The resulting signal is plotted as a function of time, yielding a time-dependent function such as intensity, absorbance, or emission. The achievable time resolution is determined by the instrument response function and the light source, often reaching femtoseconds to nanoseconds in ultrafast setups.

Common methods include pump-probe spectroscopy, time-correlated single-photon counting, streak camera measurements, and fast photodiodes. Time-resolved imaging or spectroscopy can reveal kinetic rates, transient intermediates, or carrier dynamics in materials.

Data analysis typically involves deconvolution with the instrument response, fitting with kinetic models, and sometimes constructing time-resolved spectra. Limitations include a trade-off between time and spectral resolution, signal-to-noise constraints, and potential sample damage from intense excitation.

Applications span chemical reaction dynamics, biological processes such as protein folding, semiconductor and photovoltaic carrier dynamics, and astrophysical transient phenomena.

See also: pump-probe spectroscopy, ultrafast spectroscopy, time-domain measurements.