EOS is a unique (Patent No.: US 7,817,270 B2) broadband pump-probe sub-nanosecond Transient Absorption Spectrometer designed to work with almost any ~1 kHz repetition rate laser. A complete turnkey system, EOS comprises an enclosed optical bench containing all necessary optical and optomechanical components and a 19” rack enclosing all required electronics and a PC. A rack mounted PC contains the necessary data acquisition hardware and software. The optical bench is connected to the rack by a shielded umbilical cord. This architecture allows keeping all regularly accessed parts of the system within reach, while protecting and consolidating all auxiliary components in a steel rack. Additionally, such a two-unit design facilitates quick and easy installation and relocation. The preconfigured routing optics kits offered with EOS allow for easy accommodation of various excitation sources, such as harmonics generators and OPO/OPA. Top quality hardware components from Hamamatsu, JY Horiba, Thorlabs, Newport, CVI and other industry leaders ensure high reliability and longevity of EOS and all our other spectrometers. EOS comes with advanced data analysis software, SURFACE XPLORER, capable of various types of data processing including Global Analysis. With its broad spectral coverage, high temporal resolution and a long time window, EOS will produce superb spectral and kinetic data needed for your investigations of photoexcitation events.
At any time EOS’s time resolution can be improved to femtosecond by integrating it with HELIOS, broadband pump-probe femtosecond transient absorption spectrometer.
- 2-unit design with the optical bench isolated from the electronics and detectors.
- Advanced user-friendly LabVIEW based software for instrument control and data acquisition.
- Broad probe spectral range: 350-2400 nm.
- A virtually unlimited time window. In EOS the pump-probe delay is controlled electronically, therefore the maximum time window is very close to half the repetition period of the pump laser. When coupled to a 1 kHz pump laser (such as a femtosecond amplifier) EOS’s time window is 400 microseconds. The window can be easily extended by lowering the pump laser repetition rate.
- Support for large pump beam diameters. EOS does not use an optical chopper, so any pump beam diameter can be used without sacrificing the contrast of pump-on and pump-off measurements and the transient absorption signal amplitude. This is important because when you don’t have much power out of an OPA (especially in the UV) being able to utilize the whole pump beam cross section is critical for getting good data.
- Fiber coupled high-speed spectrometers
- Optional computer controlled filter wheel for varying pump energy, etc.
- Magnetically stirred sample holder. Easily interchangeable with optional XY rastering sample holder or flow cell.
- All electronics, including spectrometers, are enclosed in a separate electronics rack connected to the optical bench by a protected umbilical cable.
- EOS utilizes a two-channel probe or “probe-reference” method. In this approach the probe beam is split into two before passing through the sample. While one arm travels through the sample, the other is sent directly to the reference spectrometer that monitors the fluctuations in the probe beam intensity. The main advantage of this technique is that it allows the user to achieve the specified signal-to-noise ratio with a lower number of averaged laser pulses. This is very important because EOS’s time window spans from nanoseconds to sub-milliseconds with the typical number of time points of >1000. When integrated with HELIOS it automatically adds the “probe-reference” feature to the HELIOS.
EOS features versatile and user-friendly LabVIEW based software for instrument control and data acquisition. The software allows for full experiment automation, so no input from the user is required for the whole experiment duration.
- Ability to toggle between linear and logarithmic time scales to accurately represent various time constants of a decay process.
- User specified initial step size, time window and the total number of time steps.
- Pseudo-random scanning of the pump-probe delay times allows to average out the low frequency noise (sample degradation, pump laser energy drifts, etc).
- Real-time histogram plotting to show the sampling distribution over the time window.
- Built-in algorithms for automatic equalizing of the sampling distribution over the whole time window. Additionally a user can switch (on the fly) to the manual mode for custom sampling distribution over the time window.
- Supports computer controlled translating sample holder
- Support pump beam shutter for increased automation.
- Supports motorized filter wheel for automated pump intensity control.
- API (Application Programming Interface) for the data acquistion sofware is provided for further experiment customization and integration with external applications. For example, studying temperature dependence on the kinetics with a computer controlled cryostat, etc. can be easily automated through the API. Another example is integration of a computer controlled ND filter wheel or an OPA to perform multiple kinetic scans at different excitation energies or wavelengths.
- Data format. The software produces a 3-Dimensional Wavelength-Time-Absorbance data matrix in a form of a .ufs file , which can be easily exported into ASCII with Surface Xplorer.
- Probe light source. EOS utilizes a built-in PCF based supercontinuum pulsed light source for probe generation.
- Time window. The maximum time window can be calculated as: (pump laser repetition period)/2-100 µs. For example for 1 kHz pump lasers it is 400 µs.
- Temporal Resolution. The instrument response function is a cross-correlation of the pump and probe pulses. The EOS probe pulse duration is <1ns.
- Probe spectral ranges
- 350-950 nm
- 800-1600 nm
- 1600-2400 nm
- Spectral Resolution
- Intrinsic spectral resolution:
- VIS – 2 nm
- NIR – 5 nm
- SWIR – 5 nm
- Spectral resolution with a 200 µm slit (recommended):
- VIS – 4 nm
- NIR – 13 nm
- SWIR – 13 nm
- Intrinsic spectral resolution:
- VIS. Custom designed fiber-coupled alignment-free spectrometer with a 1024 pixel CMOS sensor (spectral response: 200-1000 nm). Typical spectral range spans 600 nm (ie. 350-950 nm). Spectral acquisition rate – up to 2400 spectra/s. Mounted in a 19″ rack outside of the optical bench.
- NIR. Custom designed fiber-coupled alignment-free spectrometer with a 256 pixel InGaAs sensor (spectral response: 800-1600 nm). Typical spectral range spans 800 nm (ie. 800-1600 nm). Spectral acquisition rate – up to 7900 spectra/s. Mounted in a 19″ rack outside of the optical bench.
- SWIR. Custom designed fiber-coupled alignment-free spectrometer with a 256 pixel InGaAs sensor (spectral response: 1000-2600 nm). Typical spectral range spans 800 nm (ie. 1600-2400 nm). Spectral acquisition rate – up to 7900 spectra/s. Mounted in a 19″ rack outside of the optical bench.
- Optical bench: W24” x L36” x H10” (W610 x L915 x H250 mm)
- Electronics rack: W21” x L24” x H27” (W534 x L610 x H686 mm)
- Cell biology
- Materials science
- Transient spectrometry, and many more areas.
Typical examples of research topics involve studies of intra- and intermolecular such processes as:
- Electronic deactivation
- Intersystem crossing
- Intra- and intermolecular electron transfer, etc.
- “EXCITED-STATE INTRAMOLECULAR HYDROGEN TRANSFER (ESIHT) OF 1,8-DIHYDROXY-9,10-ANTHRAQUINONE (DHAQ) CHARACTERIZED BY ULTRAFAST ELECTRONIC AND VIBRATIONAL SPECTROSCOPY AND COMPUTATIONAL MODELING.”Journal of Physical Chemistry A (2014). Volume: 118, Issue: 17. Pages: 3090-3099. Omar F. Mohammed, Dequan Xiao, et al. We combine ultrafast electronic and vibrational spectroscopy and computational modeling to investigate the photoinduced excited-state intramolecular hydrogen-transfer dynamics in […]
- “ULTRAFAST LIGHT INDUCED UNUSUALLY BROAD TRANSIENT ABSORPTION IN THE SUB-BANDGAP REGION OF GESE2 THIN FILM.”Scientific reports (2014). Volume: 4. Pages: 3686. R Barik, Mukund Bapna, D a Drabold, K V Adarsh. In this paper, we show for the first time that ultrafast light illumination can induce an unusually broad transient optical absorption (TA), spanning of ≈ 200 nm in the sub-bandgap region of chalcogenide GeSe2 thin films, which we interpret as […]
- “DUAL ROLES OF DISSOLVED ORGANIC MATTER AS SENSITIZER AND QUENCHER IN THE PHOTOOXIDATION OF TRYPTOPHAN.”Environmental Science and Technology (2014). Volume: 48, Issue: 9. Pages: 4916-4924. Elisabeth M L Janssen, Paul R. Erickson, Kristopher McNeill. The photooxidation processes of tryptophan (Trp) in the presence of dissolved organic matter (DOM) were identified and quantified by steady-state photolysis experiments, laser spectroscopy and kinetic […]
- “EXCITON LOCALIZATION AND DISSOCIATION DYNAMICS IN CDS AND CDS-PT QUANTUM CONFINED NANORODS: EFFECT OF NONUNIFORM ROD DIAMETERS.”The journal of physical chemistry. B (2014). Volume: 118, Issue: 49. Pages: 14062-14069. Kaifeng Wu, William Rodríguez-Córdoba, Tianquan Lian. One-dimensional colloidal multicomponent semiconductor nanorods, such as CdSe-CdS dot-in-rod, have been extensively studied as a promising class of new materials for solar energy conversion because of the possibilities of using […]
- “TRIPLET STATE FORMATION IN PHOTOEXCITED SLIP-STACKED PERYLENE-3,4:9,10- BIS(DICARBOXIMIDE) DIMERS ON A XANTHENE SCAFFOLD.”Journal of Physical Chemistry A (2013). Volume: 117, Issue: 40. Pages: 10333-10345. Kelly M. Lefler, Kristen E. Brown, et al. Two covalent perylene-3,4:9,10-bis(dicarboximide) (PDI) dimers in which the PDI molecules are attached to a xanthene (Xan) scaffold in which the long axes of the two π-π stacked PDI molecules are slipped by […]
- “ELECTRON TRANSFER DYNAMICS IN SEMICONDUCTOR-CHROMOPHORE-POLYOXOMETALATE CATALYST PHOTOANODES.”Journal of Physical Chemistry C (2013). Volume: 117, Issue: 2, Pages: 918-924. Xu Xiang, John Fielden, et al. Triadic photoanodes have been prepared based on nanoporous films of the metal oxides ZrO2, TiO2, and SnO2, sensitizer [Ru(bpy)2(dpbpy)]2+ (P2), and polyoxometalate water oxidation catalyst […]
- “SUBPICOSECOND INTERSYSTEM CROSSING IN MONO- AND DI(ORGANOPHOSPHINE)GOLD(I) NAPHTHALENE DERIVATIVES IN SOLUTION.”Journal of the American Chemical Society (2012). Volume: 134, Issue: 36, Pages: 14808-14817. R. Aaron Vogt, Thomas G. Gray, et al. Femtosecond-to-microsecond broadband transient absorption experiments are reported for Cy(3)PAu(2-naphthyl) (1), (Cy(3)PAu)(2)(2,6-naphthalenediyl) (2), and (Cy(3)PAu)(2)(2,7-naphthalenediyl) (3), where Cy = cyclohexyl […]
- “LONG-LIVED CHARGE-SEPARATED STATES IN LIGAND-STABILIZED SILVER CLUSTERS.”Journal of the American Chemical Society (2012). Volume: 134, Issue: 29, Pages: 11856-11859. Matthew Pelton, Yun Tang, et al. Recently developed synthesis methods allow for the production of atomically monodisperse clusters of silver atoms stabilized in solution by aromatic thiol ligands, which exhibit intense absorption peaks throughout the visible and […]
- “EXCITED-STATE DYNAMICS IN 6-THIOGUANOSINE FROM THE FEMTOSECOND TO MICROSECOND TIME SCALE.”Journal of Physical Chemistry B (2011). Volume: 115, Issue: 12, Pages: 3263-3270. Christian Reichardt, Cao Guo, et al. Patients treated with the immunosuppressant and anticancer drugs 6-thioguanine, azathioprine, or mercaptopurine can metabolize and incorporate them in DNA as 6-thioguanosine. The skin of these patients is sensitive to […]
- “HOLE TRANSFER FROM SINGLE QUANTUM DOTS.”ACS Nano (2011). Volume: 5, Issue: 11, Pages: 8750-8759. Nianhui Song, Haiming Zhu, et al. Photoinduced hole transfer dynamics from single CdSe/CdS(3ML)/CdZnS(2ML)/ZnS(2ML) core/multishell quantum dots (QDs) to phenothiazine (PTZ) molecules were studied by single QD fluorescence […]
- “COMPETITION BETWEEN ENERGY AND ELECTRON TRANSFER FROM CDSE QDS TO ADSORBED RHODAMINE B.”Journal of Physical Chemistry C (2010). Volume: 114, Issue: 2, Pages: 962-969. Abdelaziz Boulesbaa, Zhuangqun Huang, et al. Understanding the dynamics of exciton quenching in quantum dots (QDs) is essential to their potential applications, such as solar cells and biological imaging. In this work, the competition between electron and energy transfer from […]
- “EXCITED-STATE DYNAMICS OF (ORGANOPHOSPHINE)GOLD(I) PYRENYL ISOMERS.”Journal of Physical Chemistry Letters (2010). Volume: 1, Issue: 8, Pages: 1205-1211. R. Aaron Vogt, Miya A. Peay, et al. Ultrafast dynamics of isomeric (tricyclohexylphosphine)gold(I) pyrenyl complexes have been measured in chloroform and cyclohexane at room temp. Internal conversion from an upper excited singlet (Sn) to the S1 state occurs […]
- “ON THE ORIGIN OF ULTRAFAST NONRADIATIVE TRANSITIONS IN NITRO-POLYCYCLIC AROMATIC HYDROCARBONS: EXCITED-STATE DYNAMICS IN 1-NITRONAPHTHALENE.”Journal of Chemical Physics (2009). Volume: 131, Issue: 22. Christian Reichardt, R. Aaron Vogt, et al. The electronic energy relaxation of 1-nitronaphthalene was studied in nonpolar, aprotic, and protic solvents in the time window from femtoseconds to microseconds. Excitation at 340 or 360 nm populates the […]