Related Experiment Video
Updated: Jun 20, 2026
08:22
Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
Pulsed frequency-modulation spectroscopy as a means for fast absorption measurements
W Lenth1, C Ortiz, G C Bjorklund
1IBM Research Laboratory, San Jose, California 95193, USA.
Optics Letters
|August 25, 2009
Summary
This study introduces pulsed frequency-modulated (FM) spectroscopy for rapid absorption measurements. This technique uses minimal light exposure to achieve ultrafast measurements, significantly reducing the light needed compared to traditional methods.
Area of Science:
- Spectroscopy
- Laser Physics
- Physical Chemistry
Background:
- Traditional absorption measurement techniques often require substantial light exposure.
- Frequency-modulated (FM) light offers potential for enhanced spectroscopic sensitivity.
- Pulsed laser systems enable high temporal resolution in measurements.
Purpose of the Study:
- To develop and demonstrate an ultrafast absorption measurement technique.
- To reduce the overall light exposure required for absorption spectroscopy.
- To leverage pulsed FM spectroscopy for rapid analysis of absorption features.
Main Methods:
- Utilizing short pulses of frequency-modulated (FM) light for absorption measurements.
- Detecting the heterodyne beat signal resulting from FM spectrum distortion by absorption.
- Employing a single short laser pulse to observe signal buildup.
Main Results:
- Demonstrated beat signal buildup significantly above noise levels within 1 microsecond.
- Showcased the ability to probe entire absorption structures with only a few laser pulses.
- Achieved ultrafast absorption measurements with drastically reduced light exposure.
Conclusions:
- Pulsed FM spectroscopy enables significantly faster absorption measurements.
- This technique requires orders of magnitude less light exposure than traditional methods.
- The method is effective for rapid probing of absorption features.
Related Concept Videos
01:17NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
01:16Spectrophotometry: Introduction
Spectrophotometry is the quantitative measurement of the absorption, reflection, diffraction, or transmission of electromagnetic radiation through a material as a function of the intensity and wavelength of the radiation. A spectrophotometer is a device used to measure the change in the radiation intensity caused by its interaction with the material.
The essential components of a spectrophotometer include a source of electromagnetic radiation, a slot for placing a material to be analyzed, and a...
The essential components of a spectrophotometer include a source of electromagnetic radiation, a slot for placing a material to be analyzed, and a...
01:14UV–Vis Spectrometers
The absorbance of UV and visible (UV–visible) radiations is measured using a UV–visible spectrophotometer. Deuterium lamps, which emit UV radiation, and tungsten lamps, which produce radiation in the visible region, are used as light sources in UV–visible spectrophotometers. A monochromator or prism is used for diffraction grating, i.e., to split the incoming radiation into different wavelengths. A system of slits is used to focus the desired wavelength on the sample cell. Samples for...
01:23Atomic Spectroscopy: Absorption, Emission, and Fluorescence
Atomic spectroscopy is a vital tool in elemental analysis, both qualitatively and quantitatively. It can be broadly divided into optical spectroscopy, mass spectroscopy, and X-ray spectroscopy methods. The optical spectroscopic methods are atomic absorption spectroscopy (AAS), atomic emission spectroscopy (AES), and atomic fluorescence spectroscopy (AFS). The first step in all three methods is atomization, where the solid, liquid, or solution-phase samples are converted into gas-phase atoms and...
01:27Fast Reactions
Fast reactions occurring in times shorter than the time needed to mix reactants pose a unique challenge for investigation. In a liquid-phase continuous-flow system, reactants A and B are swiftly pushed into the mixing chamber, where mixing occurs within 1 ms. The reaction mixture then flows through an observation tube, and one measures light absorption to determine species concentrations at various points of the tube. This method is most appropriate when relatively large volumes of reactants...
01:22Atomic Absorption Spectroscopy: Instrumentation
An atomic absorption spectrophotometer (AAS) comprises several components: a radiation source, an atomizer, a monochromator, and a detector. The radiation source can be a hollow-cathode lamp (HCL) or an electrodeless-discharge lamp (EDL), both of which provide a narrow emission line of the required wavelength. However, some instruments use continuum sources and high-resolution monochromators to achieve a narrow range of radiation.
The atomizer used in AAS can be either a flame atomizer or an...
The atomizer used in AAS can be either a flame atomizer or an...