The transient absorption (TA) experiment allows quantitative characterization of time-dependent absorption of an optically excited sample. Two light pulses are required: femtosecond narrow-bandwidth pump pulse to excite the sample and delayed broad-bandwidth probe pulse to measure the changes in sample transmittance. The resulting difference absorption signal is measured as a function of the probe wavelength and the temporal delay between the pump and probe pulses.
The TA spectrum is much more elaborate than, e.g., a steady-state absorption or fluorescence decay spectrum. It provides information not only on the excited states of the system but also on all the intermediate evolutionary transients and non-emissive states both on the ground and the excited states.
HARPIA-TA can be equipped with a microscopy module HARPIA-MM, enabling spatially-resolved pump-probe measurements with a spatial resolution down to 5 μm. The HARPIA-MM module features a brightfield mode to observe the sample and determine the pump-probe spot location and transmission and reflection modes to carry out the pump-probe measurements.
- Down to 2 μm spatial resolution
- Broadband and monochromatic probe options
- Motorized XYZ sample stage
- Transmission, specular and diffuse reflection geometry
- Market-leading sensitivity
- 330 nm – 24 μm spectral range
- Probe delay ranges from 2 to 8 ns
- Pump pulse energies down to nJ
- Cryostat and peristaltic pump support
- 100 fs – 20 ps tunable pulse duration
- 4 mJ maximum pulse energy
- 20 W maximum output power
- Single-shot – 1 MHz repetition rate
- Automated harmonic generators (up to 5th harmonic)
- 190 fs – 20 ps tunable pulse duration
- 2 mJ maximum pulse energy
- 80 W maximum output power
- Single-shot – 2 MHz repetition rate
- Air-cooled version
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