The Therien Group Laser Laboratory is equipped with a Spectra-Physics Solstice ACE Ti:Sapphire femtosecond Regen-amplifier which produces ~80 fs, 800 nm, 5mJ output at 1kHz rep rate. This Ti:S regen amplifier is equipped with two custom designed Light Conversion HARPIA ultrafast spectroscopy systems for pump-probe transient-absorption spectroscopy probing the UV/Vis/NIR/SWIR (~320 – 2600 nm) and MIR/LWIR (2 – 13 µm) spectral regimes, in addition to a home-built transient-absorption spectrometer. A Light Conversion TOPAS-C optical parametric amplifier (OPA) provides an optical pump/excitation tunable across the 280 – 2600 nm spectral domain for all spectroscopic configurations. In the home-built spectrometer a white-light continuum probe is generated by using a small portion of the laser fundamental (800 nm) to pump a sapphire crystal with detection provided by a multi-channel CCD camera (300 – 1100 nm) and liquid nitrogen cooled InGaAs diode array (800 – 1600 nm). When configured for HARPIA 1 UV/Vis/NIR probe (LEFT FIGURE) a range of nonlinear crystals are available to provide white-light continua spanning the 320 – 1600 nm spectral range when pumped by the 800 nm fundamental, with detection enabled by multi-channel Si NMOS (200 – 1100 nm) and TE-cooled InGaAs (900 – 2600 nm) detectors. HARPIA 1 can also be uniquely configured to probe the SWIR spectral domain (CENTER FIGURE). In this configuration, a second TOPAS-C OPA is used to generate a ~1500 – 2100 nm laser pulse which is used to pump a nonlinear crystal and provide white-light continua to probe up to 2600 nm. Both of the HARPIA 1 configurations support a flash photolysis extension that utilizes an NKT Photonics SuperK COMPACT supercontinuum white light laser to probe the 450 – 2400 nm range with up to ms delays under identical excitation conditions as the analogous fs probe experiments. HARPIA 2 (RIGHT FIGURE) is separately configured for single-wavelength MIR/LWIR probe experiments. Within this configuration, the second OPA is interfaced for difference frequency generation to provide optical probes spanning 2 – 13 µm for detection with two single-channel MCT detectors in a probe-reference configuration.
In addition, the lab houses a nanosecond laser flash photolysis spectrometer, LP920 from Edinburgh, which allows us to study the excited states of organic and inorganic molecules in ns ~ ms time regime, with a Q switched Nd:YAG laser and optical parametric oscillator, which produces 410~2400nm, ~5ns pulse. Our custom Raman system utilizes a PI Acton SP2360i 300 mm spectrograph outfitted with three gratings to cover spectral information from 250 to 1700 nm. Light detection through the spectrograph is provided via two cameras: a PI Acton PIXIS 400 BR CCD (250 to 1100 nm, 1300 x 400 pixels, 20 um pixel size, back-illuminated deep-depletion for enhanced sensitivity throughout the NIR), and a PI Acton OMA V 1024 liquid nitrogen cooled InGaAs CCD that covers the 800- 1700 nm spectral regime. Five laser lines are available and interchangeable on this system; these include: 532 nm diode-pumped solid state (100 mW; Cobolt AB Lasers), 633 nm He-Ne (20 mW; Lasos), and 785 nm (120 mW), 980 nm (500 mW), and 1064 nm (1000 mW) diode lasers from Torsana Laser Technology AB. Our laboratory is also equipped with a streak camera for picosecond fluorescence measurement and a steady state absorption and emission spectrometer.