Encyclopedia > letter P > pump–probe measurements

Pump–probe Measurements

Definition: techniques for investigating ultrafast phenomena, where a pump pulse excites a sample and a probe pulse is used for probing the sample after an adjustable delay time

German: Pump-Probe-Messungen

Categories: optical metrology, methods

How to cite the article; suggest additional literature

Author: Dr. Rüdiger Paschotta

Pump–probe measurements can be used to obtain information on ultrafast phenomena. The general principle is the following. A sample (e.g. a SESAM) is hit by some pump pulse, which generates some kind of excitation (or other modification) in the sample. After an adjustable time delay (controlled with an optical delay line), a probe pulse hits the sample, and its transmission or reflection is measured. By monitoring the probe signal as a function of the time delay, it is possible to obtain information on the decay of the generated excitation, or on other processes initiated by the pump pulses. The probe signal is typically averaged over many pulses, and a fast photodetector is not required. The temporal resolution is fundamentally limited only by the pulse duration of pump and probe pulses.

reflectivity change in a SESAM, caused by a short pulse — Figure 1: Reflectivity change in a semiconductor saturable absorber, hit by a short pulse at t = 0.

The wavelengths of pump and probe beam do not need to be identical. A so-called two-color pump–probe measurement, based on two synchronized sources of short pulses (e.g. a laser and an optical parametric oscillator, or two parametric oscillators pumped with the same laser) has additional capabilities in ultrafast laser spectroscopy. It is vital in such cases to ensure tight synchronization of the different laser sources with a very low relative timing jitter, as the jitter could otherwise spoil the attainable temporal resolution.

Pump–probe measurements can be used, for example, to monitor the recovery of a saturable absorber after its excitation, the speed of diffusion of photoexcited carriers, or the melting of a sample after being hit by an intense pulse.

Pump–probe methods are also used in various methods of time-resolved spectroscopy.

Suppliers

The RP Photonics Buyer's Guide contains 8 suppliers for pump--probe measurement equipment. Among them:

APE

The APE ScanDelay is a variable optical delay line, allowing the introduction of a well-defined time delay into an optical path – for example, for pump–probe measurements. The delay is periodically controlled by a fast scanning shaker at a frequency of up to 20 Hz.

The heart of APE’s optical delay line series is a special linear translation stage that is supplied together with appropriate control and drive electronics. The linear drive has been designed especially for optical applications. It combines low moving mass with compactness, reaching a high speed, as well as high precision and resolution. The delay drive moves frictionless, has a large and precise travel range, and allows for very small displacements without any stick-slip-effects.

The control electronic contains the motion driver and a quartz stabilized signal synthesizer. It can be synchronized with an external clock for a precise, phase-locked scanner movement.

TOPTICA Photonics

TOPTICA contributes to the field of pump–probe measurements with newest fiber technology which is outstanding in performance and versatility. A single laser system can be equipped with various outputs that are intrinsically optically synchronized down to the attosecond level. All of these can be configured individually to satisfy the experimental needs: Pulse durations as short as 15 fs or broad tuning ranges of 490 nm to 700 nm, 850 nm to 1000 nm or 980 nm to 2200 nm are available. Within the third generation of TOPTICA’s ultrafast fiber lasers a novel, versatile toolbox is available to realize even more advanced pump–probe spectroscopy schemes. The FemtoFiber dichro bioMP outputs two different wavelength simultaneously (1050/780 nm at 150 fs), while the system can control the relative time delay of both colors and the GDD as well.

Questions and Comments from Users

Here you can submit questions and comments. As far as they get accepted by the author, they will appear above this paragraph together with the author’s answer. The author will decide on acceptance based on certain criteria. Essentially, the issue must be of sufficiently broad interest.

Please do not enter personal data here; we would otherwise delete it soon. (See also our privacy declaration.) If you wish to receive personal feedback or consultancy from the author, please contact him e.g. via e-mail.

By submitting the information, you give your consent to the potential publication of your inputs on our website according to our rules. (If you later retract your consent, we will delete those inputs.) As your inputs are first reviewed by the author, they may be published with some delay.

If you like this page, please share the link with your friends and colleagues, e.g. via social media:

These sharing buttons are implemented in a privacy-friendly way!

Code for Links on Other Websites

If you want to place a link to this article in some other resource (e.g. your website, social media, a discussion forum, Wikipedia), you can get the required code here.

HTML link on this article:

<a href="https://www.rp-photonics.com/pump_probe_measurements.html">
Article on Pump&ndash;probe Measurements</a>
in the <a href="https://www.rp-photonics.com/encyclopedia.html">
RP Photonics Encyclopedia</a>

With preview image (see the box just above):

<a href="https://www.rp-photonics.com/pump_probe_measurements.html">
<img src="https://www.rp-photonics.com/previews/pump_probe_measurements.png"
 alt="article" style="width:400px"></a>

For Wikipedia, e.g. in the section "==External links==":

* [https://www.rp-photonics.com/pump_probe_measurements.html
article on 'Pump&ndash;probe Measurements' in the RP Photonics Encyclopedia]