What is pump-probe technique?
The pump-probe technique enables us to measure ultrafast phenomena inside matter such as the movement of atoms or electron excitations, thanks to very short laser pulses. In order to do this, a very short and intense laser pulse, the “pump”, is sent on an object to excite it.
How do pump-probe experiments work?
Pump-probe experiment. A pump-probe experiment utilizes two light beams, a pump beam and a probe beam, that interact with a sample material. The pump beam initiates a sample response. A probe beam monitors the response, usually with a lower optical intensity that does not significantly affect the sample.
What is transient spectroscopy?
Transient spectroscopy encompasses a powerful set of techniques for probing and characterizing the electronic and structural properties of short-lived excited states (transient states) of photochemically or photophysically relevant molecules.
What is transient absorption spectrum?
What is Transient Absorption Spectroscopy? Transient absorption (TA) spectroscopy, also known as flash photolysis, is a pump-probe spectroscopic technique utilised to measure the photogenerated excited state absorption energies and associated lifetimes of molecules, materials, and devices.
What is a probe laser?
Laser probes are used to facilitate photocoagulation in order to treat things like retinal tears. Unlike light pipes, however, directional laser probes exist [9,10] (Fig. 6.2). These include two tubes: a rigid outer tube and a precurved nitinol inner tube. Models of tubes with both a laser and illumination exist.
What is probe pulse?
A second time delayed pulse (probe) is then used to monitor the temporal evolution of the SHG signal (see below). The relaxation dynamics of the non-equilibrium distribution can be used to understand the microscopic energy loss mechanisms of the surface electrons.
What are ultrafast lasers used for?
Ultrafast lasers can be used for high quality micromachining of brittle materials like glass and are often used for scribing and cutting with flexible geometries and high quality edges.
What is photoluminescence spectroscopy?
Photoluminescence spectroscopy, often referred to as PL, is when light energy, or photons, stimulate the emission of a photon from any matter. It is a non-contact, nondestructive method of probing materials.
How does fluorescence spectroscopy work?
Fluorescence spectroscopy uses a beam of light that excites the electrons in molecules of certain compounds, and causes them to emit light. That light is directed towards a filter and onto a detector for measurement and identification of the molecule or changes in the molecule.
What is steady state absorption spectroscopy?
Steady-state absorption uses a continuous-wave beam of light to irradiate the sample and the fraction of light absorbed is determined through transmission or reflectance measurements. Steady-state emission techniques measure the electromagnetic radiation emitted upon deactivation of excited states.
How do ultrafast lasers work?
Ultrafast lasers are based on techniques like mode-locking to form a train of pulses and have recently been successful due to the relatively new advancements in photonics. Such developments in laser technology have enabled the generation of pulses ranging between a few femtoseconds to tens of attoseconds.
How does femtosecond spectroscopy work?
development by Zewail During the process, known as femtosecond spectroscopy, molecules were mixed together in a vacuum tube in which an ultrafast laser beamed two pulses. The first pulse supplied the energy for the reaction, and the second examined the ongoing action.