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

Superconductor01:24

Superconductor

1.1K
A substance that reaches superconductivity, a state in which magnetic fields cannot penetrate, and there is no electrical resistance, is referred to as a superconductor. In 1911, Heike Kamerlingh Onnes of Leiden University, a Dutch physicist, observed a relation between the temperature and the resistance of the element mercury. The mercury sample was then cooled in liquid helium to study the linear dependence of resistance on temperature. It was observed that, as the temperature decreased, the...
1.1K
¹³C NMR: ¹H–¹³C Decoupling01:04

¹³C NMR: ¹H–¹³C Decoupling

1.1K
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
1.1K
Propagation Speed of Electromagnetic Waves01:30

Propagation Speed of Electromagnetic Waves

3.3K
Electromagnetic waves are consistent with Ampere's law. Assuming there is no conduction current Ampere's law is given as:
3.3K
Atomic Nuclei: Larmor Precession Frequency01:11

Atomic Nuclei: Larmor Precession Frequency

1.2K
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession,...
1.2K
The de Broglie Wavelength02:32

The de Broglie Wavelength

25.4K
In the macroscopic world, objects that are large enough to be seen by the naked eye follow the rules of classical physics. A billiard ball moving on a table will behave like a particle; it will continue traveling in a straight line unless it collides with another ball, or it is acted on by some other force, such as friction. The ball has a well-defined position and velocity or well-defined momentum, p = mv, which is defined by mass m and velocity v at any given moment. This is the typical...
25.4K
Deactivation Processes: Jablonski Diagram01:25

Deactivation Processes: Jablonski Diagram

608
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...
608

You might also read

Related Articles

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

Sort by
Same author

Motor tract integrity in gait pattern clusters of patients with chronic Stroke: A diffusion tensor imaging and motion capture study.

Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology·2026
Same author

Realization of a linear-birefringence exceptional point in a high-finesse Fabry-Pérot cavity.

Optics express·2026
Same author

Efficacy and safety of high-definition transcranial direct current stimulation combined with digital rehabilitation on upper limb function in stroke patients: study protocol for a randomized, double-blind, sham-controlled confirmatory trial.

Trials·2026
Same author

Clustering of fNIRS-Based Cortical Activation Patterns During Digital Upper Limb Motor Tasks in Individuals With Stroke.

IEEE transactions on neural systems and rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society·2026
Same author

Colored dissolved organic matter estimation using Sentinel-2 imagery in small-scale reservoir: Classification and regression-based data resampling approaches.

Environmental research·2025
Same author

Exploring the Relationship Between Depression and Attention-Deficit/Hyperactivity Disorder Symptoms in Children Using Brain Activity Monitoring.

Psychiatry investigation·2025
Same journal

Bi-layer photonic random meta-composite for cryogenic thermal control by ultra-broadband scattering matched reflectance.

Light, science & applications·2026
Same journal

Interferometric scattering for optical tomoslicing of transparent solids.

Light, science & applications·2026
Same journal

Multi-dimensional spatial-temporal projection ultrafast compressed imaging.

Light, science & applications·2026
Same journal

Expanded field of view light-field extended-reality displays with metalens array.

Light, science & applications·2026
Same journal

Experimental observation of counter-intuitive features of photonic bunching.

Light, science & applications·2026
Same journal

High-speed and high-sensitivity multi-gas detection based on parallel heterodyne LITES sensor.

Light, science & applications·2026
See all related articles

Related Experiment Video

Updated: Jun 14, 2025

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing
06:16

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing

Published on: April 25, 2019

7.5K

Thresholdless coherence in a superradiant laser.

Seung-Hoon Oh1, Jinuk Kim2, Junseo Ha1

  • 1Department of Physics and Astronomy & Institute of Applied Physics, Seoul National University, Seoul, Korea.

Light, Science & Applications
|September 5, 2024
PubMed
Summary
This summary is machine-generated.

Thresholdless lasers can now produce always-coherent light. This new superradiance approach eliminates the conventional lasing threshold, maintaining coherence even at low photon numbers.

More Related Videos

Generation and Coherent Control of Pulsed Quantum Frequency Combs
06:42

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Published on: June 8, 2018

8.9K
Rejection of Fluorescence Background in Resonance and Spontaneous Raman Microspectroscopy
15:04

Rejection of Fluorescence Background in Resonance and Spontaneous Raman Microspectroscopy

Published on: May 18, 2011

13.1K

Related Experiment Videos

Last Updated: Jun 14, 2025

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing
06:16

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing

Published on: April 25, 2019

7.5K
Generation and Coherent Control of Pulsed Quantum Frequency Combs
06:42

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Published on: June 8, 2018

8.9K
Rejection of Fluorescence Background in Resonance and Spontaneous Raman Microspectroscopy
15:04

Rejection of Fluorescence Background in Resonance and Spontaneous Raman Microspectroscopy

Published on: May 18, 2011

13.1K

Area of Science:

  • Quantum Optics
  • Laser Physics

Background:

  • Conventional lasers have a minimum input power (lasing threshold) to start oscillation.
  • Approaching unity for the β parameter was thought to eliminate this threshold, but coherence issues persisted below unity photon numbers.

Purpose of the Study:

  • To demonstrate an always-coherent thresholdless laser.
  • To overcome the limitations of conventional thresholdless laser designs.

Main Methods:

  • Utilizing superradiance in a high-Q cavity with two-level atoms in a quantum superposition state.
  • Observing lasing without the conventional threshold around unity photon number.

Main Results:

  • Superradiant lasing was achieved without the conventional threshold.
  • Photon statistics remained near-coherent even below unity intracavity photon number.
  • Coherence improved with reduced coupling constant and excited-state amplitude.

Conclusions:

  • The developed method enables always-coherent thresholdless lasers.
  • This research opens possibilities for practical applications using quantum dots, NV centers, and doped ions.