Cavity ring-down lossmeter using a pulsed light emitting diode source and photon counting

2006 ◽  
Vol 18 (1) ◽  
pp. 147-154 ◽  
Author(s):  
Jonathan E Thompson ◽  
Kyle Myers
Keyword(s):  
Light Emitting Diode ◽  
Photon Counting ◽  
Pulsed Light ◽  
Light Emitting ◽  
Cavity Ring Down

scholarly journals Control Measures for SARS-CoV-2: A Review on Light-Based Inactivation of Single-Stranded RNA Viruses

Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 737 ◽  
Author(s):  
Joshua Hadi ◽  
Magdalena Dunowska ◽  
Shuyan Wu ◽  
Gale Brightwell
Keyword(s):  
Large Scale ◽  
Rna Virus ◽  
Light Emitting Diode ◽  
Red Light ◽  
Ultrashort Pulses ◽  
Control Measures ◽  
Pulsed Light ◽  
Light Emitting ◽  
The Family ◽  
Modelling Studies

SARS-CoV-2 is a single-stranded RNA virus classified in the family Coronaviridae. In this review, we summarize the literature on light-based (UV, blue, and red lights) sanitization methods for the inactivation of ssRNA viruses in different matrixes (air, liquid, and solid). The rate of inactivation of ssRNA viruses in liquid was higher than in air, whereas inactivation on solid surfaces varied with the type of surface. The efficacy of light-based inactivation was reduced by the presence of absorptive materials. Several technologies can be used to deliver light, including mercury lamp (conventional UV), excimer lamp (UV), pulsed-light, and light-emitting diode (LED). Pulsed-light technologies could inactivate viruses more quickly than conventional UV-C lamps. Large-scale use of germicidal LED is dependent on future improvements in their energy efficiency. Blue light possesses virucidal potential in the presence of exogenous photosensitizers, although femtosecond laser (ultrashort pulses) can be used to circumvent the need for photosensitizers. Red light can be combined with methylene blue for application in medical settings, especially for sanitization of blood products. Future modelling studies are required to establish clearer parameters for assessing susceptibility of viruses to light-based inactivation. There is considerable scope for improvement in the current germicidal light-based technologies and practices.

Inactivation of Salmonella and quality changes in wheat flour after pulsed light-emitting diode (LED) treatments

2020 ◽  
Vol 121 ◽  
pp. 166-177 ◽  
Author(s):  
Samir Subedi ◽  
Lihui Du ◽  
Amritha Prasad ◽  
Barun Yadav ◽  
M.S. Roopesh
Keyword(s):  
Wheat Flour ◽  
Light Emitting Diode ◽  
Quality Changes ◽  
Pulsed Light ◽  
Light Emitting

Efficiency of photosynthesis in continuous and pulsed light emitting diode irradiation

1995 ◽  
Vol 44 (3) ◽  
pp. 261-269 ◽  
Author(s):  
Daniel J. Tennessen ◽  
Raymond J. Bula ◽  
Thomas D. Sharkey
Keyword(s):  
Light Emitting Diode ◽  
Pulsed Light ◽  
Light Emitting

Effect of pH on Aqueous Phenylalanine Studied Using a 265-nm Pulsed Light-emitting Diode

2008 ◽  
Vol 1130 (1) ◽  
pp. 300-304 ◽  
Author(s):  
Alexander M. Macmillan ◽  
Colin D. McGuinness ◽  
Kulwinder Sagoo ◽  
David McLoskey ◽  
John C. Pickup ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Pulsed Light ◽  
Effect Of Ph ◽  
Light Emitting

scholarly journals Inactivation of Escherichia Coli and Salmonella Using 365 and 395 nm High Intensity Pulsed Light Emitting Diodes

Foods ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 679 ◽  
Author(s):  
Amritha Prasad ◽  
Michael Gänzle ◽  
M. S. Roopesh
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
High Intensity ◽  
Light Exposure ◽  
Light Emitting Diode ◽  
Antibacterial Efficacy ◽  
Pulsed Light ◽  
Light Emitting ◽  
E Coli ◽  
Novel Approach

High intensity pulsed light emitting diode (LED) treatment is a novel approach to inactivate foodborne pathogens. The objective of this study was to evaluate the antibacterial potential of high intensity 365 (UV-A) and 395 nm (NUV-Vis) LED treatments against Escherichia coli and Salmonella enterica at high and low water activity (aw) conditions, and to understand the influence of different process parameters on their antibacterial efficacy. Bacteria at high (in phosphate buffer saline, PBS) and low aw (aw = 0.75) conditions were treated with both the LEDs with specific doses at a fixed distance from the LEDs. The 365 nm LED showed more effectiveness in reducing the dried bacteria compared to 395 nm LED. The dry E. coli showed more resistance to LED treatments compared to Salmonella. The 365 and 395 nm LED treatments with ~658 J/cm2 dose resulted in reductions of 0.79 and 1.76 log CFU/g of Salmonella, respectively, on 0.75 aw pet foods. The LED treatments increased the surface temperature, resulting in water loss in the treated samples. This study showed that the dose, duration of light exposure, bacterial strain, and aw played a major role in the antibacterial efficacy of the 365 and 395 nm LEDs.

scholarly journals Effect of Multispectral Pulsed Light-Emitting Diodes on the Growth, Photosynthetic and Antioxidant Response of Baby Leaf Lettuce (Lactuca sativa L.)

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 762
Author(s):  
Jurga Miliauskienė ◽  
Robert F. Karlicek ◽  
Elsebeth Kolmos
Keyword(s):  
Light Emitting Diode ◽  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Photosynthetic Performance ◽  
Duty Ratio ◽  
Pulsed Light ◽  
Carotenoid Concentration ◽  
Antioxidant Power ◽  
Light Emitting

The effect of multicolor pulsed light-emitting diode (LED) irradiation on lettuce “Defender” growth, photosynthetic performance and antioxidant properties was studied. The experiments were designed to compare the continuous and pulsed lighting (0.5, 1 kHz; 50% duty ratio) effects of B450, G520, R660 and FR735 lighting components, maintaining total diurnal integral light quantity (DLI 14.4 mol m−2 day−1) constant during the 16-h photoperiod. The results showed that lettuce grown under pulsed irradiation displayed superior growth performance, including a significant enhancement of fresh (~32%) and dry biomass (~36%) and leaf area (~48%). Lettuce cultivated in both pulsed light treatments was characterized by the higher photosynthetic rate, chlorophyll (a,b) and carotenoid concentration. However, the total phenol and antioxidant properties in lettuce were more dependent on the specific pulsed light frequency. Only treatment with 1 kHz frequency was effective for higher phenol content, 2,20-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) free radical scavenging activity and Fe2+ reducing antioxidant power (FRAP). Thus, our results propose the role of pulsed LED light in improving the photosynthetic efficiency and antioxidative properties of lettuce plants cultivated indoors. In the future, pulsed lighting techniques should be included in the development of artificial lighting systems in controlled environment agriculture (CEA) to produce high-quality crops with the possibility to save electricity.

scholarly journals Development of an optical photon-counting imager with a monolithic Geiger Avalanche Photodiode array

2020 ◽  
Author(s):  
Takeshi Nakamori ◽  
Yuga Ouchi ◽  
Risa Ogihara ◽  
Toshio Terasawa ◽  
Yuhei Kato ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Photon Counting ◽  
Avalanche Photodiode ◽  
Light Emitting ◽  
Optical Photon ◽  
Timing Resolution ◽  
Geiger Mode ◽  
Photodiode Array ◽  
The Time Domain ◽  
Optical Astronomy

Abstract We have developed a sensor system based on an optical photon-counting imager with high timing resolution, aiming for highly time-variable astronomical phenomena. The detector is a monolithic Geiger-mode avalanche photodiode array customized in a Multi-Pixel Photon Counter with a response time on the order of nanoseconds. This paper evaluates the basic performance of the sensor and confirms the gain linearity, uniformity, and low dark count. We demonstrate the system’s ability to detect the period of a flashing light-emitting diode, using a data acquisition system developed to obtain the light curve with a time bin of 100 μs. The Crab pulsar was observed using a 35-cm telescope without cooling, and the equipment detected optical pulses with a period consistent with the data from the radio ephemeris. Although improvements to the system will be necessary for more reliability, the system has been proven to be a promising device for exploring the time-domain optical astronomy.

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