What is Ultrafast processes?
Ultrafast science is the study of processes in atoms, molecules, or materials that occur in millionths of a billionth of a second or faster. This timescale is called femtoseconds, or 10-15 seconds. With ultrafast science, researchers use short pulses of photons, electrons, and ions to probe matter.
How does femtosecond spectroscopy work?
During the process, known as femtosecond spectroscopy, molecules were mixed together in a vacuum tube in which an ultrafast laser beamed two pulses. The characteristic spectra, or light patterns, from the molecules were then studied to determine the structural changes of the molecules.
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 a laser spectroscopy used for?
CHEMICAL APPLICATIONS. Laser spectroscopy provides chemists with an extremely versatile tool for analytical spectrochemistry, for probing the dynamic behavior of chemical reactions, and for determining molecular structure and energy levels.
What is ground state bleaching?
Bleaching of ground state refers to depletion of the ground state carriers to excited states. Stimulated emission follows the fluorescence spectrum of the molecule and is Stokes shifted relative to and often still overlaps with the bleach signal.
HOW DOES A femtosecond laser work?
Femtosecond (FS) laser is an infrared laser with a wavelength of 1053nm. FS laser like Nd: YAG laser works by producing photodisruption or photoionization of the optically transparent tissue such as the cornea. Reducing the pulse duration reduces the amount of collateral tissue damage.
How do you calculate femtosecond?
The word femtosecond is formed by the SI prefix femto and the SI unit second. Its symbol is fs. A femtosecond is equal to 1000 attoseconds, or 1/1000 picosecond. Because the next higher SI unit is 1000 times larger, times of 10−14 and 10−13 seconds are typically expressed as tens or hundreds of femtoseconds.
How can a laser cool something?
Atoms can be cooled using lasers because light particles from the laser beam are absorbed and re-emitted by the atoms, causing them to lose some of their kinetic energy. After thousands of such impacts, the atoms are chilled to within billionths of a degree above absolute zero.
What is the basic use of spectroscopy?
Spectroscopy is used as a tool for studying the structures of atoms and molecules. The large number of wavelengths emitted by these systems makes it possible to investigate their structures in detail, including the electron configurations of ground and various excited states.
Which type of laser is used in spectroscopy?
A frequently used method is laser absorption spectroscopy, where a tunable narrow-linewidth laser (frequently a single-frequency laser) is tuned through some wavelength range, and the light absorption in some sample (i.e., a reduction of optical power of the probe beam) is measured as a function of that wavelength.
What is a corneal Lenticule?
A suction ring lifts and flattens the cornea and helps keep the eye from moving. The laser sculpts a disc-shaped piece of cornea below the surface of your eye. This is the “lenticule” that gives the surgery its name.
What are the methods of ultrafast laser spectroscopy?
Several methods of ultrafast laser spectroscopy have been developed to support materials science and biology applications. In fluorescent upconversion, the fluorescent sample is pumped by a femtosecond pulse and the fluorescence is up-converted using an optically gated pulse to generate sum frequency radiation.
What makes our best bipolar ultrafast rectifier diodes so good?
Our best bipolar ultrafast rectifier diodes maintain heavy R&D progress illustrated here by the ‘RQ’ soft diode series for resonant converters. Thanks to the high-voltage D²PAK package, our new diode series improves the creepage distance and facilitates compliance with the IEC 60664-1 worldwide standard.
What is ultrashort laser spectroscopy?
Ultrafast spectroscopy uses ultrashort laser pulses to study atomic and molecular structure and dynamics on extremely short time scales. Several methods of ultrafast laser spectroscopy have been developed to support materials science and biology applications.
How can we probe charge carrier motion with ultra-fast spectroscopy?
The advancement of ultra-fast spectroscopy enables the direct probing of charge carrier motion on short timescales by THz pulses (Hegmann et al., 2006; Hendry et al., 2004, 2005) allowing for the probing of carrier transport in the ps time range. The measurement is a conventional time-resolved pump–probe experiment (Fig.