Facilities

We innovate and apply state-of-the-art spectroscopic techniques to address some of the most complex challenges in chemistry. Below is a brief overview of the methods we use.

High-power, kHz, femtosecond laser system

Coherent Astrella (800 nm, 7 mJ, 1 kHz, 35 fs)

This powerful laser system represents the key driver of our spectroscopic beamlines. The system can produce high pulse energy (7 mJ) in a short time window (35 fs), while possessing the industry-standard level of reliability. In our laboratory, we convert the initial near-infrared wavelength to mid-infrared or extreme-ultraviolet to perform transient-absorption spectroscopy tailored for low-energy quasiparticle states or characteristic elemental absorption edges.

XUV: gas-phase HHG beamline

This beamline consists of a few-cycle pulse generation system and a series of vacuum chambers equipped with special XUV optics. Our XUV pulses are produced by high-harmonic generation using rare-gas media, and spectrally optimized to cover the range of 30-70 eV.

Sample requirements: less than 100-nm-thick solid samples, XUV absorption in the 30-70 eV range

MIR: mid-infrared cryogenic beamline

This beamline is designed to perform mid-infrared driving of various semiconductor systems from two-dimensional materials to organic semiconductors. The beamline is further equipped with a closed-cycle helium cryostat to improve the signal sensitivity to low-energy quantum states.

Sample requirements: responsive to visible excitation (1.3-2.4 eV), thin film or bulk solid samples with a flat, smooth surface

Vis: strong-field liquid-phase beamline

This beamline uses few-femtosecond visible excitation produced through our home-built multi-plate supercontinuum system. This beamline is further combined with a wire-guided liquid microfilm to realize strong-field experiments of liquid-phase molecular dynamics.

Sample requirements: solubility to water or organic solvents; solid thin films can be studied as well

Organic-2D sample fabrication

We have in-house production capabilities for new optical samples using van der Waals crystals and organic semiconductors. We are capable of mechanical exfoliation, dry transfer, and wet transfer. We can further apply deposition of organic molecular systems using vapor deposition and spin coating. The University of Michigan houses a state-of-the-art nanofabrication facility at the North Campus, and we are a frequent user for our material fabrication and characterization.

Van der Waals materials and molecular film deposition

We fabricate mixed-dimensional heterostructure materials using van der Waals materials and organic semiconductors. Our wet lab is further equipped with home-built optical characterization tools, including optical microscope, Raman spectroscopy, photoluminescence spectroscopy, and second-harmonic-generation spectroscopy.

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