Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Optics: Statistics light the way

23.05.2013
Revelation of how photoreceptive cells in the eye distinguish between different light sources could pave the way for a novel class of optical devices
Millions of years of evolution have molded our eyes into highly sensitive optical detectors, surpassing even many man-made devices. Now, Leonid Krivitsky and his co-workers at the A*STAR Data Storage Institute and the A*STAR Institute of Medical Biology, Singapore, have shown that the photoreceptor cells found in the retina are even sensitive to the statistical properties of light. This ability could be harnessed in 'bioquantum' interfaces, a novel class of optical devices that use biological systems to detect the quantum nature of light.

Light comprises discrete bundles of energy known as photons. A 40-Watt light bulb, for example, creates more than 1019 (a one followed by 19 zeros) visible photons every second. Nevertheless, attenuated sources that generate light pulses containing just a few photons are also useful. In such ultralow-intensity light pulses, the statistical distribution of photons emitted in a single pulse depends on the light source.

Warm light sources such as light-bulb filaments generate photons in bunches. Lasers, in contrast, create photons randomly — each is emitted independently of the next. Krivitsky and his co-workers experimentally demonstrated that rod photoreceptor cells in the eye can distinguish between pulses of light from either a laser or a thermal light based only on these differing distributions. “Showing that such cells can assess photon statistics provides hope for accessing the quantum properties of light using biodetectors,” says Krivitsky.

Krivitsky and his team trapped a photoreceptor cell from a frog on the end of a suction pipette. Then they fired green-light laser pulses at the cell through an optical fiber. The same device could also imitate a thermal light source when they placed a rotating disk of ground glass and an aperture into the beam path.

They observed that rhodopsin molecules in the cell absorbed the incoming photons, which generated an ion current. The researchers amplified and measured this current as the average number of photons in each light pulse increased. They noticed a much sharper increase in detected current for the laser light than the pseudothermal pulses. This is because, while the average photon number is the same, an individual pseudothermal pulse was more likely to have a low number of photons. The photon distribution of the laser pulses, on the other hand, was much narrower.

The two types of photon emitters investigated in these experiments are examples of ‘classical’ light sources. “The next step is to investigate quantum light, such as pulses with a fixed number of photons,” notes Krivitsky.

The A*STAR-affiliated researchers contributing to this research are from the Data Storage Institute and the Institute of Medical Biology

Journal information

Sim, N., Cheng, M. F., Bessarab, D., Jones, C. M. & Krivitsky, L. A. Measurement of photon statistics with live photoreceptor cells. Physical Review Letters 109, 113601 (2012)

A*STAR Research | Research asia research news
Further information:
http://www.research.a-star.edu.sg/research/6674
http://www.researchsea.com

More articles from Physics and Astronomy:

nachricht Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible
30.05.2017 | ICFO-The Institute of Photonic Sciences

nachricht New Method of Characterizing Graphene
30.05.2017 | Universität Basel

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New Method of Characterizing Graphene

Scientists have developed a new method of characterizing graphene’s properties without applying disruptive electrical contacts, allowing them to investigate both the resistance and quantum capacitance of graphene and other two-dimensional materials. Researchers from the Swiss Nanoscience Institute and the University of Basel’s Department of Physics reported their findings in the journal Physical Review Applied.

Graphene consists of a single layer of carbon atoms. It is transparent, harder than diamond and stronger than steel, yet flexible, and a significantly better...

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

3D printer inks from the woods

30.05.2017 | Life Sciences

How circadian clocks communicate with each other

30.05.2017 | Life Sciences

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible

30.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>