Nanosecond Transient Absorption Spectrometer

Probe Spectral Range: 350-2200 nm
Sub-ns Time Resolution
EOS is a unique (Patent No.: US 7,817,270 B2) broadband pump-probe nanosecond Transient Absorption Spectrometer designed to work with a wide variety of pulsed lasers. A complete turn-key system, EOS measures transients with sub-ns time resolution over an easily adjustable time window. At any time, the EOS time resolution can be improved to femtosecond by integrating it with HELIOS, our broadband pump-probe femtosecond transient absorption spectrometer.
Features & Specs

Broad probe spectral range

350 - 950 nm

800 - 1600 nm

1600 - 2200 nm

Spectral resolution optimized for transient absorption

For transient absorption higher spectral resolution is not always better. It is important to map out all the spectral features, but it is also critical to deliver enough probe light to each pixel of the detector. These two parameters counteract - with not enough probe light the data can be noisy; and with not enough spectral resolution some important features can be missed. Therefore, we configure the spectral resolution to be sufficient for resolving what is practical in condensed phase experiments, but not excessively high to allow for enough probe light on the detector.

Spectral Range

Intrinsic spectral resolution

Spectral resolution with a 200 µm slit (recommended)


2 nm

4 nm


5 nm

13 nm


5 nm

13 nm

Sub-ns resolution with a flexible time window

In contrast to conventional flash photolysis based on the continuous photoelectric method, EOS is pump-probe spectrometer. It utilizes a sub-nanosecond pulsed probe light source – a PCF (photonic crystal fiber) based supercontinuum laser.

The pulse duration of this probe light source determines the time resolution of the spectrometer (< 1 ns). This eliminates the need for fast photodetectors, fast digitizers, and high-power probe light sources.

In EOS the pump-probe delay is controlled electronically, and the maximum time window is close to the repetition period of the pump laser. The time window can be extended by lowering the pump laser repetition rate.

Large sample area

The spacious (210 mm x 300 mm) sample compartment allows for easy mounting of cryostats and temperature-controlled sample holders. Also, simply having more space around the sample makes working with your samples easier.

Lower probe and pump power on the sample

Focusing the probe tightly onto the sample allows to reduce the excitation energy and minimize sample degradation. This is particularly important with solid-state samples (thin films, etc.). Especially those that cannot be easily translated during the experiment. In the standard configuration, the EOS probe beam waist in the sample is <100 µm. As a result, the typical excitation energy required is hundreds of nJ/pulse. Additionally, this beam size permits studying small samples.


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.

The data acquisition software features:

  • Automated alignment of the pump beam

  • Computer-controlled switching between UV/VIS, NIR, and SWIR modes.

  • Supports computer-controlled translating sample holder.

  • Supports pump beam shutter.

  • Supports motorized filter wheel for automated pump intensity control.

  • The user specified the initial step size, time window, and the total number of time steps.

  • Pseudo-random scanning of the pump-probe delay times averages out low-frequency noise.

  • 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.

  • API (Application Programming Interface) for EOS is provided for further experiment customization and integration with external


Some research areas where HELIOS IR is useful are:


Materials science




Transient spectrometry

Cell biology

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.

Brochures & Examples

EOS Brochure

EOS. Millisecond Transient Absorption Of Congo Red. Nanosecond Pump.

EOS. Millisecond Transient Absorption of Iron Oxide. (Time window: 50 ms).

EOS. Nanosecond Transient Absorption Of TPP. Nanosecond Pump.

EOS. Nanosecond Transient Absorption Of ZnTPP. Femtosecond Pump.

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