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Artist's illustration of the heart of an optical lattice clock, in which multiple atoms are individually confined in a landscape of periodic potential wells made by interfering laser beams. The lattice allows highly stable and ultranarrow atomic radiative transitions to be probed for applications in temporal metrology.
Frequency combs generated by femtosecond lasers are powerful tools for high-precision optical spectroscopy and metrology. Theodor Hänsch, who received part of the Nobel Prize for Physics in 2005 for his work in this field, spoke to Nature Photonics about how frequency combs have changed science.
Single photons emitted from a quantum dot can be slowed down using a hybrid semiconductor–atomic interface. Nika Akopian from Delft University of Technology in The Netherlands explained to Nature Photonics how this non-classical light storage system works.
The successful integration of a single-photon source with a slow-light medium creates important opportunities for photon synchronization and marks a step towards the development of distributed networks for quantum information processing.
Alternative electrode materials and device geometries that avoid the use indium tin oxide — an expensive and brittle material widely used for making transparent electrodes in organic solar cells — are now coming to fruition.
Combining semiconductor quantum dots and atomic systems allows the light emitted from a quantum dot to be temporarily stored. Here, scientists describe a hybrid semiconductor-atomic interface that can slow down a single photon emitted from a quantum dot by 15 times its temporal width. The findings are attractive for the implementation of quantum memories and quantum repeaters.
Based on peristaltic nematogen microflows in polydimethylsiloxane, scientists demonstrate an optofluidic modulator that exhibits a symmetric 250 µs response and can operate at frequencies of up to 1 kHz.
Experimental investigation of the reverse-Doppler shift of electromagnetic waves has previously been restricted to the microwave regime. Here, direct confirmation of the Doppler effect is reported at the infrared wavelength of 10.6 µm using a moving photonic crystal exhibiting a negative refractive index.
Many X-ray imaging techniques require transmission geometries, which place severe restrictions on the samples being imaged. Here, a reflection geometry lensless X-ray imaging method is demonstrated. This technique may allow single-shot imaging of surfaces and films such as organic photovoltaic materials and field-effect transistor devices, or Bragg planes in a single crystal.
This focus issue brings together a collection of articles that describe the importance and latest progress of optical frequency combs, optical lattice clocks and quantum metrology, as well as techniques for measuring Casimir forces in complex microstructured geometries and ultrashort laser pulses — all of which are essential for realizing next-generation optical metrology.