Transient Absorption Microscopy

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
  • BiBurst
  • 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
  • BiBurst
  • Air-cooled version

Carrier Transport Across a CdSxSe1–x Lateral Heterojunction Visualized by Ultrafast Microscopy

D. D. Blach, W. Zheng, H. Liu, A. Pan, and L. Huang, The Journal of Physical Chemistry C 21 (124), 11325-11332 (2020).

Femtosecond Transient Absorption Microscopy of Singlet Exciton Motion in Side-Chain Engineered Perylene-Diimide Thin Films

R. Pandya, R. Y. S. Chen, Q. Gu, J. Gorman, F. Auras, J. Sung, R. Friend, P. Kukura, C. Schnedermann, and A. Rao, The Journal of Physical Chemistry A 13 (124), 2721-2730 (2020).

Compressive imaging of transient absorption dynamics on the femtosecond timescale

O. Denk, K. Zheng, D. Zigmantas, and K. Žídek, Optics Express 7 (27), 10234 (2019).

Long-range ballistic propagation of carriers in methylammonium lead iodide perovskite thin films

J. Sung, C. Schnedermann, L. Ni, A. Sadhanala, R. Y. S. Chen, C. Cho, L. Priest, J. M. Lim, H. Kim, B. Monserrat et al., Nature Physics 2 (16), 171-176 (2019).

Ultrafast Tracking of Exciton and Charge Carrier Transport in Optoelectronic Materials on the Nanometer Scale

C. Schnedermann, J. Sung, R. Pandya, S. D. Verma, R. Y. S. Chen, N. Gauriot, H. M. Bretscher, P. Kukura, and A. Rao, The Journal of Physical Chemistry Letters 21 (10), 6727-6733 (2019).

Spatially segregated free-carrier and exciton populations in individual lead halide perovskite grains

S. Nah, B. Spokoyny, C. Stoumpos, C. M. M. Soe, M. Kanatzidis, and E. Harel, Nature Photonics 5 (11), 285-288 (2017).

Two Birds with One Stone: Tailoring Singlet Fission for Both Triplet Yield and Exciton Diffusion Length

T. Zhu, Y. Wan, Z. Guo, J. Johnson, and L. Huang, Advanced Materials 34 (28), 7539-7547 (2016).