Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Infrared (IR) Spectroscopy: Overview01:09

Infrared (IR) Spectroscopy: Overview

When electromagnetic radiation passes through a material, atoms or molecules transition from a lower to a higher energy state by absorbing radiation corresponding to the energy difference between the two states. The absorption of infrared (IR) radiation causes transitions between vibrational energy levels in a molecule. Therefore, IR spectroscopy is a useful analytical tool for determining the molecular structure of molecules.
Different compounds display unique properties due to their...
UV–Vis Spectroscopy: Molecular Electronic Transitions01:16

UV–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,...
IR Spectroscopy: Molecular Vibration Overview01:24

IR Spectroscopy: Molecular Vibration Overview

When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental vibrational motions that result in infrared absorption can be classified as stretching or bending vibrations.
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
Molecular Spectroscopy: Absorption and Emission01:14

Molecular Spectroscopy: Absorption and Emission

Molecules possess discrete energy levels called quantum states. Unlike atoms, which have simpler energy levels, molecules possess additional rotational and vibrational energy levels. Each energy level is separated by an energy gap, with the gaps between adjacent electronic, vibrational, and rotational levels varying significantly. The three types of energy levels in a diatomic molecule are shown in Figure 1.
Applications of IR Spectroscopy: Overview01:11

Applications of IR Spectroscopy: Overview

The non-destructive nature and ability to provide valuable chemical information make IR spectroscopy a versatile technique with broad applications in various scientific and industrial fields. IR spectroscopy is commonly used to identify and characterize organic and inorganic compounds. It provides information about the functional groups present in a molecule and the bonding between atoms. This helps in the structural elucidation of compounds during organic synthesis, pharmaceutical research,...
IR Spectrometers01:25

IR Spectrometers

There are two main infrared (IR) spectrophotometers: dispersive IR spectrometers and Fourier transform infrared (FTIR) spectrometers. In a dispersive IR spectrometer, a beam of infrared radiation produced by a hot wire is divided into two parallel equal-intensity beams using mirrors. One beam passes through the sample, while another is a reference beam. The beams then move through the monochromator, which separates the radiations into a continuous spectrum of different frequencies. The...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Synthesis and Luminescent Properties of a Novel White Phosphor BiOF:Tm<sup>3+</sup>,Dy<sup>3</sup>.

Journal of fluorescence·2026
Same author

Effects of Voriconazole on the Safety, Pharmacokinetics and Pharmacodynamics of Ciprofol (HSK3486), a Novel Intravenous Anaesthetic, in Healthy Participants: A Prospective, Randomized, Crossover Clinical Trial.

Drug design, development and therapy·2026
Same author

Discovery of Crystallized and Weakly Coupled Aggregates of Pseudocyanine Iodide.

The journal of physical chemistry. B·2026
Same author

Investigation on the effects and mechanisms of nano-ZnO in mitigating frost heave damage of water conveyance structures in cold regions.

Scientific reports·2025
Same author

Single-cell sequencing reveals the response mechanisms of vascular endothelial cells to glucocorticoids in diabetic retinopathy.

PloS one·2025
Same author

Chemical Evolution of Double Covalent Aptamers for Sustained Protein Degradation and Improved Cytotoxicity in NK-Cell-Mediated Tumor Therapy.

Journal of the American Chemical Society·2025

Related Experiment Video

Updated: May 18, 2026

Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing
10:42

Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing

Published on: March 22, 2019

Spectroscopic study of transparency current in mid-infrared quantum cascade lasers.

Dmitry G Revin1, Randa S Hassan, Andrey B Krysa

  • 1Department of Physics and Astronomy, The University of Sheffield, Sheffield, UK. d.revin@sheffield.ac.uk

Optics Express
|October 6, 2012
PubMed
Summary

Transparency current in quantum cascade lasers is crucial, especially at higher temperatures. This study reveals it significantly impacts threshold current in InGaAs/AlGaAs lasers, regardless of active region design.

More Related Videos

Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies
09:38

Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies

Published on: December 18, 2015

Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems
06:54

Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems

Published on: June 23, 2023

Related Experiment Videos

Last Updated: May 18, 2026

Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing
10:42

Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing

Published on: March 22, 2019

Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies
09:38

Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies

Published on: December 18, 2015

Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems
06:54

Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems

Published on: June 23, 2023

Area of Science:

  • Semiconductor Physics
  • Optoelectronics
  • Quantum Electronics

Background:

  • Quantum cascade lasers (QCLs) are vital semiconductor devices for mid-infrared applications.
  • Understanding the factors influencing their threshold current is key to improving performance.
  • The role of transparency current in QCL operation, particularly in InGaAs/AlGaAs systems, requires further investigation.

Purpose of the Study:

  • To directly measure and analyze the origins of transparency current in 5 µm InGaAs/AlGaAs quantum cascade lasers.
  • To compare the impact of different active region designs on transparency current.
  • To quantify the contribution of transparency current to the threshold current over a range of temperatures.

Main Methods:

  • Broadband transmission measurements were performed on laser waveguides under sub-threshold conditions.
  • Measurements were conducted across a temperature range of 80-280 K.
  • Two active region designs were evaluated: one with double-LO-phonon relaxation and another without resonant LO-phonon assisted depopulation.

Main Results:

  • Transparency current values were successfully determined for both active region designs.
  • The study found that transparency current constitutes over 70% of the threshold current at high temperatures.
  • This significant contribution was observed irrespective of the specific active region design employed.

Conclusions:

  • Transparency current is a dominant factor in determining the threshold current of 5 µm InGaAs/AlGaAs QCLs at elevated temperatures.
  • Active region design has a limited effect on the substantial contribution of transparency current to the threshold current.
  • These findings provide direct insight into QCL operational mechanisms and inform future device optimization.