Related Experiment Video
Updated: Jun 26, 2026
06:53
Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
Orientation-dependent multiphoton ionization in wide band gap crystals
M Gertsvolf1, H Jean-Ruel, P P Rajeev
1University of Ottawa, Ottawa, Ontario, Canada, K1N 6N5.
Physical Review Letters
|December 31, 2008
Summary
Nonlinear absorption in crystalline dielectrics depends on sample orientation due to electron effective mass directionality. Multiphoton interactions with femtosecond laser pulses locally probe materials without structural damage, as shown with crystal quartz.
Area of Science:
- Solid-state physics
- Materials science
- Laser-matter interactions
Background:
- Nonlinear optical phenomena are crucial for advanced material processing and characterization.
- Understanding laser-matter interactions in crystalline dielectrics requires knowledge of electronic band structure and electron dynamics.
- Femtosecond laser pulses offer precise energy deposition, enabling localized material modification and probing.
Purpose of the Study:
- To investigate the influence of crystalline anisotropy on nonlinear absorption.
- To explore the use of multiphoton absorption as a localized probing technique.
- To assess the structural stability of crystalline dielectrics under intense femtosecond laser irradiation.
Main Methods:
- Utilizing intense femtosecond laser pulses (45 fs) to irradiate various crystalline dielectric samples.
- Measuring nonlinear absorption as a function of sample orientation relative to the laser polarization.
- Employing multiphoton absorption as an in-situ probe of material properties.
- Conducting post-irradiation structural analysis of crystal quartz.
Main Results:
- Nonlinear absorption was found to be dependent on the crystallographic orientation of the dielectric samples.
- This orientation dependence is attributed to the directional variation of the electron effective mass.
- The multiphoton interaction serves as a localized probe, applicable throughout the material.
- Crystal quartz exhibited no structural changes after repeated exposure to the laser focal region.
Conclusions:
- Crystalline anisotropy significantly impacts nonlinear optical absorption.
- Electron effective mass directionality is a key factor governing laser-matter interactions in dielectrics.
- Femtosecond laser-induced multiphoton absorption is a viable, non-destructive localized probing method.
- Crystal quartz demonstrates high structural resilience to intense ultrashort laser pulses.
Related Concept Videos
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this process,...
01:29Determination of Crystal Structures
In the late 1800s, the revelation that light extended beyond visible wavelengths led to the discovery of X-rays by Wilhelm Roentgen. Recognized as high-energy electromagnetic radiation with short wavelengths, X-rays prompted exploration into their interaction with crystals. Max von Laue proposed in 1912 that the periodic arrangement of atoms, ions, or molecules in crystals would cause them to diffract X-rays, a hypothesis confirmed through experiments with copper sulfate and zinc sulfide...
01:25Deactivation Processes: Jablonski Diagram
Luminescence, the emission of light by a substance that has absorbed energy, is a process that involves the interaction of molecules with light. The energy-level diagram, or Jablonski diagram, is a graphical representation of these interactions, illustrating the various states and transitions a molecule can undergo. In a typical Jablonski diagram, the lowest horizontal line represents the ground-state energy of the molecule, which is usually a singlet state. This state represents the energies...
01:21IR Absorption Frequency: Hybridization
Hydrocarbons such as alkanes, alkenes, and alkynes show characteristic C–H stretching absorption bands. These IR stretching frequencies depend on the hybridization of the involved carbon atom and can be explained in terms of the s character of each hybridized atomic orbital.
Among the sp, sp2, and sp3 hybridized orbitals, sp orbitals have the maximum s character (50%). Consequently, the electrons are held more closely to the nucleus, resulting in stronger and shorter C–H bonds that stretch at a...
Among the sp, sp2, and sp3 hybridized orbitals, sp orbitals have the maximum s character (50%). Consequently, the electrons are held more closely to the nucleus, resulting in stronger and shorter C–H bonds that stretch at a...
02:58Crystal Field Theory - Octahedral Complexes
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
01:19Mass Analyzers: Common Types
The quadrupole mass analyzer consists of four cylindrical metal rods arranged in a diamond carrying a DC voltage and a radio-frequency AC voltage. The motion of ions through the quadrupole depends on the field strength, causing only ions of a certain m/z to resonate successfully and strike the detector at a given field strength. Though the transmission rate for these analyzers is high, the exact elemental composition of the sample is not determined because of low resolution; however, they are...