Nav: Home

Subnatural-linewidth biphotons generated from a Doppler-broadened hot atomic vapor cell

October 19, 2016

Entangled photon pairs, termed as biphotons, have been the benchmark tool for experimental quantum optics. The quantum-network protocols based on photon-atom interfaces have stimulated a great demand for single photons with bandwidth comparable to or narrower than the atomic natural linewidth. In the past decade, laser-cooled atoms have often been used for producing such biphotons, but the apparatus is too large and complicated for engineering.

Led by Shengwang Du, Associate professor of physics at the Hong Kong University of Science and Technology (HKUST), a group of scientists were able to produce subnatural-linewidth (<6MHz) biphotons from a Doppler-broadened (530 MHz) hot atomic vapour cell. This method marks a significant breakthrough in the field, as it greatly simplifies production process of narrowband biphotons.

Their findings were published in Nature Communications on Sep 23, 2016 (doi:10.1038/ncomms12783).

"Subnatural-linewidth biphotons with controllable waveforms have used to be produced from spontaneous four-wave mixing in cold atoms at a temperature of about 10 μK assisted with electromagnetically induced transparency or cavity," said Du. "But such systems require expert knowledge in laser cooling and trapping. A cold-atom apparatus is not only expensive, but also large and complicated in its vacuum-optical-electronic-mechanical configuration. Moreover, operating cold atoms for producing paired photons requires a complex timing control."

"In our study, we find a novel way to use a hot paraffin-coated 87Rb vapour cell at 63°C to successfully produce biphotons with controllable bandwidth (1.9-3.2MHz) and coherence time (47-94ns). This is the best result in the world so far for generating narrowband biphotons from a hot vapor cell." Du continued.

The two key elements to make narrowband biphoton generation feasible are the paraffin coating and the spatially separated optical pumping. The long ground-state coherence time preserved by the paraffin coating enables efficient optical pumping for the flying atoms, which is spatially separated from the biphoton generation volume.

Du said, "Hot atomic vapour cell is simple in configuration, operation and maintenance, and it is a continuous biphoton source. This result may lead towards miniature narrowband biphoton sources for practical quantum applications and engineering."
-end-


Hong Kong University of Science and Technology

Related Scientists Articles:

Scientists discover a 2-D magnet
A team led by the University of Washington and the Massachusetts Institute of Technology has for the first time discovered magnetism in the 2-D world of monolayers, or materials that are formed by a single atomic layer.
Scientists present El Nino
The ecological effects of the strong 2015-2016 El Niño. Carbon burial in aquatic ecosystems.
Russian scientists slowed down aging
A group of Russian and Swedish scientists just published a breakthrough paper, reporting results of a joint study by Lomonosov Moscow State University and Stockholm university.
Scientists develop new antibiotic for gonorrhea
Scientists at the University of York have harnessed the therapeutic effects of carbon monoxide-releasing molecules to develop a new antibiotic which could be used to treat the sexually transmitted infection gonorrhea.
Biodiversity needs citizen scientists
Could birdwatching or monitoring tree blossoms in your community make a difference in global environmental research?
Scientists need your help to spot ladybirds
Scientists are calling on people who are out in their garden this summer to take part in The Ladybird Challenge and help discover how far an alien ladybird species in the UK is affecting other insects, including a wasp parasite.
Scientists ID genes associated with educational attainment
A USC co-author of the study says the genes that are correlated with educational attainment are expressed in the brain during prenatal development.
What values are important to scientists?
While many people are marking today scrutinizing the virtues of their Valentines, Michigan State University revealed a first-of-its-kind study on the virtues and values of scientists.
Scientists take nanoparticle snapshots
An international team of researchers led by X-ray scientist Christoph Bostedt of the US Department of Energy's (DOE) Argonne National Laboratory and Tais Gorkhover of DOE's SLAC National Accelerator Laboratory used two special lasers to observe the dynamics of a small sample of xenon as it was heated to a plasma.
Why do scientists chase unicorns?
Scientists chase unicorns because if they could prove the existence of the magical beasts, the world would be a better place.

Related Scientists Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#529 Do You Really Want to Find Out Who's Your Daddy?
At least some of you by now have probably spit into a tube and mailed it off to find out who your closest relatives are, where you might be from, and what terrible diseases might await you. But what exactly did you find out? And what did you give away? In this live panel at Awesome Con we bring in science writer Tina Saey to talk about all her DNA testing, and bioethicist Debra Mathews, to determine whether Tina should have done it at all. Related links: What FamilyTreeDNA sharing genetic data with police means for you Crime solvers embraced...