Navigation Links
Blocked holes can enhance rather than stop light going through

Conventional wisdom would say that blocking a hole would prevent light from going through it, but Princeton University engineers have discovered the opposite to be true. A research team has found that placing a metal cap over a small hole in a metal film does not stop the light at all, but rather enhances its transmission.

In an example of the extraordinary twists of physics that can occur at very small scales, electrical engineer Stephen Chou and colleagues made an array of tiny holes in a thin metal film, then blocked each hole with an opaque metal cap. When they shined light into the holes, they found that as much as 70 percent more light came through when the holes were blocked than when they were open.

"The common wisdom in optics is that if you have a metal film with very small holes and you plug the holes with metal, the light transmission is blocked completely," said Chou, the Joseph Elgin Professor of Engineering. "We were very surprised."

Chou said the result could have significant implications and uses. For one, he said, it might require scientists and engineers to rethink techniques they have been using when they want to block all light transmission. In very sensitive optical instruments, such as microscopes, telescopes, spectrometers and other optical detectors, for example, it is common to coat a metal film onto glass with the intention of blocking light. Dust particles, which are unavoidable in metal film deposition, inevitably create tiny holes in the metal film, but these holes have been assumed to be harmless because the dust particles become capped and surrounded by metal, which is thought to block the light completely.

"This assumption is wrong -- the plug may not stop the leakage but rather greatly enhance it," Chou said.

He explained that in his own field of nanotechnology, light is often used in a technique called photolithography to carve ultrasmall patterns in silicon or other materials. Thin metal film patterns on a glass plate serve as a mask, directing light through certain locations of the plate and blocking other locations. Given the new finding, engineers ought to examine whether the mask blocks the light as expected, Chou said.

Conversely, Chou said, the newly discovered "blocking" technique might be used in situations when a boost in light transmission is desired. In near-field microscopy, for example, scientists view extremely fine details by passing light through a hole as tiny as billionths of a meter in diameter. With the new technique, the amount of light passing through the hole -- and thus the amount of information about the object being viewed -- can be increased by blocking the hole.

Chou and colleagues stumbled on the phenomenon of enhanced light transmission through a blocked hole in their research on developing ultrasensitive detectors that sense minute amounts of chemicals, with uses ranging from medical diagnostics to the detection of explosives. These detectors use a thin metal film with an array of holes and metal disks to boost faint signals produced when laser light encounters a molecule, allowing much greater sensitivity in identifying substances.

In one of their experimental detectors, the researchers studied transmission of light through an array of tiny holes that were 60 nanometers (billionths of a meter) in diameter and 200 nanometers apart in a gold film that was 40 nanometers thick. Each tiny hole was capped with a gold disk that was 40 percent larger than the hole. The disks sat on top of the holes with a slight gap between the metal surface and the disks.

The researchers pointed a laser at the underside of the film and tested to see if any of the laser light went through the holes, past the caps, and could be detected on the other side. To their surprise, they found that the total light transmission was 70 percent higher with the holes blocked by the metal disks than without blockers. The researchers repeated the same experiment shining the light in the opposite direction -- pointing at the side with the caps and looking for transmitted light under the film -- and found the same results.

"We did not expect more light to get through," Chou said. "We expected the metal to block the light completely."

Chou said the metal disk acts as a sort of "antenna" that picks up and radiates electromagnetic waves. In this case, the metal disks pick up light from one side of the hole and radiate it to the opposite side. The waves travel along the surface of the metal and leap from the hole to the cap, or vice versa depending on which way the light is traveling. Chou's research group is continuing to investigate the effect and how it could be applied to enhance the performance of ultrasensitive detectors.

Contact: Steven Schultz
Princeton University, Engineering School

Related biology technology :

1. Second U.S.-Egypt Collaborative Clinical Study Blocked by New York State Department of Health (NYSDOH), This Time on Complications of Diabetes
2. Women More Likely Than Men to Avoid Amputation After Minimally Invasive Therapy for Blocked Leg Arteries
3. VAP(R) Cholesterol Test From Atherotech Covers an Additional 9 Million of Florida Insured
4. Atherotech to Exhibit VAP(R) Cholesterol Test at American Heart Association Scientific Sessions 2008
5. VAP(R) Cholesterol Test Helps Researchers Identify Treatment Effects of Combination Therapy
6. VAP Cholesterol Test Helps In Search For New Heart Disease Drugs
7. Atherotech to Exhibit the VAP(R) Cholesterol Test at ACC.09 in Orlando
8. First Application to Fight High Cholesterol Launches on the iPhone and iPod Touch
9. Atherotech to Exhibit its VAP(R) Cholesterol Test at Internal Medicine 2009 in Philadelphia
10. VAP(R) Cholesterol Test Now Available at ANY LAB TEST NOW(R)
11. Box maker, Wildcat Wholesale, Makes Cryogenic Freezer Storage Boxes Affordable By Selling Directly To Labs
Post Your Comments:
Related Image:
Blocked holes can enhance rather than stop light going through
(Date:10/9/2015)... Pa. and ROCKVILLE, Md. ... Inc. ("ITI"), a privately-held biotechnology company developing next ... announced that it has entered into an exclusive ... LAMP-vax products for the treatment or prevention of ... execution of the agreement, Immunomic Therapeutics will receive ...
(Date:10/9/2015)... ... October 09, 2015 , ... Leading microbial genomics startup uBiome today ... understand the relationship between weight management and the microbiome. The study uses the ResearchKit ... using an iPhone app. , The uBiome app is available as a free download ...
(Date:10/8/2015)... -- Genetic testing for mutations beyond those currently recommended in ... at risk of having a child with cystic fibrosis, ... American Society of Human Genetics (ASHG) Annual Meeting, which ... . The study is one of four that ... presenting at the conference this week demonstrating the clinical ...
(Date:10/8/2015)... BALTIMORE, Maryland , October 8, 2015 /PRNewswire/ ... .   --> Goldman ... specializing in the small cap and microcap sectors, ... sponsored research report on PharmaCyte Biotech, Inc. (OTCQB ... company focused on developing and preparing treatments for ...
Breaking Biology Technology:
... (, ) announced today the publication ... written and edited by Richard S. Lord and ... by Bralley and Lord, Laboratory,Evaluations in Molecular Medicine, ... arm of Metametrix Inc., a leader in nutritional ...
... Exemplary Work ... of Oncology ... winner,and finalists of its 2008 Extraordinary Healer Award for Oncology ... Annual,Congress. Ortho Biotech Products, L. P. sponsored the award, which ...
... Biotech Inc. (TSX:,ONC, NASDAQ: ONCY) announced today that ... study of intravenous REOLYSIN(R) in patients with,sarcomas metastatic ... Society of,Clinical Oncology (ASCO) website at ... . The abstract is entitled "A Phase II,Study ...
Cached Biology Technology:
(Date:10/5/2015)... October 5, 2015 ... for NXT-ID, Inc. (NASDAQ: NXTD ), a biometric ... --> ) releases the ... NXTD ), a biometric authentication company focused on ... Technology Group ( ) releases the ...
(Date:10/1/2015)... , Oct. 1, 2015  Biometrics includes ... analysing human body characteristics, such as fingerprints, eye ... purposes. Adoption of biometrics technology has been constantly ... the last five years. In addition to the ... is fingerprint recognition, other means of biometric authentication ...
(Date:9/30/2015)... GARDENS, Fla. , Sept. 30, 2015  The ... this month issued another key ruling in favor of ... determination that Korean fingerprint scanner company Suprema and its ... Act of 1930, a trade provision that declares it ... import trade, by infringing two of Crossmatch,s patents, the ...
Breaking Biology News(10 mins):
... blended biodiesel fuels purchased from small-scale retailers, researchers at ... the blends do not contain the advertised amount of ... sampled pure biodiesel and blends from more than a ... listed as 20 percent biodiesel (commonly known as B20), ...
... complex has multiple causes. It,s sometimes hard to classify ... than any other disease -- an estimated $690 million ... a team of Kansas State University researchers is stepping ... Department of Agriculture, the team is analyzing data from ...
... and wisest mythology allude to the snake as a ... legend surrounding this proverbial predator may not be based ... Virginia recently discovered, the common fear of snakes is ... were capable of surviving the dangers of an uncivilized ...
Cached Biology News:
Human ABCG2 MAb (Clone 5D3)...
... purified Formulation: 50mM Tris-HCl, pH ... 0.2mM PMSF, 1mM benzamidine, 0.1% ... PP2A1 (Protein Phosphatase 2A1) partially ... sulfate precipitation, QSepharose,amino-hexyl agarose, Superdex ...
... The Beacon 2000 One-Step FP Standardization ... high and low fluorescence polarization values ... of the Beacon 2000 System. It ... polarization values generated by their instrument ...
Although each Beacon 2000 System includes one preinstalled sample chamber (size specified at time of order), optional chambers are available and easily retrofit by the user....
Biology Products: