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
  • Detectors
    • 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.
  • Dimensions
    • 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)


  • Photophysics
  • Photochemistry
  • Photobiology
  • Cell biology
  • Materials science
  • Nano-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.

Selected Publications

Data Examples

For data examples please visit our Apps Lab page.