Zobrazeno 1 - 10
of 101
pro vyhledávání: '"Petri Kärhä"'
Publikováno v:
Maham, K, Kärhä, P, Manoocheri, F & Ikonen, E 2022, ' Optical power scale realization using the predictable quantum efficient detector ', Journal of Physics: Conference Series, vol. 2149, no. 1, 012006 . https://doi.org/10.1088/1742-6596/2149/1/012006
Aalto University
Aalto University
We report realization of scales for optical power of lasers and spectral responsivity of laser power detectors based on a predictable quantum efficient detector (PQED) over the spectral range of 400 nm–800 nm. The PQED is characterized and used to
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b8be976f02fcd6f30127d779b3fa1812
https://cris.vtt.fi/en/publications/8545df2e-f03a-4a06-bc0c-346aa86c168d
https://cris.vtt.fi/en/publications/8545df2e-f03a-4a06-bc0c-346aa86c168d
Publikováno v:
Askola, J, Kärhä, P, Baumgartner, H, Porrasmaa, S & Ikonen, E 2022, ' Effect of adaptive control on the LED street luminaire lifetime and on the lifecycle costs of a lighting installation ', Lighting Research and Technology, vol. 54, no. 1, pp. 75-89 . https://doi.org/10.1177/14771535211008179
Funding Information: The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Aalto University Energy Efficiency Research Program (AEF) and by the Academy of Finland Flagship P
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::986d65c1222ebe33cb372c980133b9d8
https://cris.vtt.fi/en/publications/8db935d1-c0fc-471b-9ab9-d01bdaa4a60c
https://cris.vtt.fi/en/publications/8db935d1-c0fc-471b-9ab9-d01bdaa4a60c
Publikováno v:
Askola, J, Maham, K, Krh, P & Ikonen, E 2021, ' Increased detector response in optical overfilled measurements due to gas lens formation by nitrogen flow through the entrance aperture ', Metrologia, vol. 58, no. 5, 055008 . https://doi.org/10.1088/1681-7575/ac0e7b
According to our experimental results, a nitrogen flow used to prevent dust and moisture entering a detector may influence measurements performed with trap detectors in overfilled conditions. A stable light source was measured with a wedged trap dete
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4a7d0ddc69f9bdbfbf5dcc29185f96d0
https://cris.vtt.fi/en/publications/ba62e75d-25a2-4df9-a7e8-a9e56a69dca6
https://cris.vtt.fi/en/publications/ba62e75d-25a2-4df9-a7e8-a9e56a69dca6
Autor:
Petri Kärhä, Janne Askola, Benjamin Oksanen, Kinza Maham, Kasperi Kylmanen, Vo Huynh, Erkki Ikonen, Hans Baumgartner
Publikováno v:
Kärhä, P, Baumgartner, H, Askola, J, Kylmänen, K, Oksanen, B, Maham, K, Huynh, V & Ikonen, E 2020, ' Measurement setup for differential spectral responsivity of solar cells ', Optical Review, vol. 27, no. 2, pp. 195-204 . https://doi.org/10.1007/s10043-020-00584-x
We have developed a setup for measuring differential spectral responsivities of unifacial and bifacial solar cells under bias light conditions. The setup uses 30 high-brightness LEDs for generating a quasi-monochromatic light source covering the wave
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::afb91427a12edf7cddf78cedc956c303
https://cris.vtt.fi/en/publications/2ac62aa3-6d56-477f-b2eb-8efee557bc51
https://cris.vtt.fi/en/publications/2ac62aa3-6d56-477f-b2eb-8efee557bc51
Publikováno v:
Baumgartner, H, Oksanen, B, Karha, P & Ikonen, E 2019, ' Optical Characterization of III-V Multijunction Solar Cells for Temperature-Independent Band Gap Features ', IEEE Journal of Photovoltaics, vol. 9, no. 6, 8827497, pp. 1631-1636 . https://doi.org/10.1109/JPHOTOV.2019.2933190
A recently developed method to characterize the band gap energies of III-V optosemiconductors was utilized to determine temperature-invariant band gap features of multijunction solar cells. The method is based on measuring electroluminescent spectra
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7f80eed921369454e1756ffe6edd4f37
https://cris.vtt.fi/en/publications/d6bf661b-da73-46be-961b-ee6224f1c3ca
https://cris.vtt.fi/en/publications/d6bf661b-da73-46be-961b-ee6224f1c3ca
Autor:
Farshid Manoocheri, Janne Askola, Omar El Gawhary, Tomi Pulli, Saulius Nevas, Erkki Ikonen, Petri Kärhä, Steven van den Berg
Publikováno v:
Pulli, T, Nevas, S, El Gawhary, O, van den Berg, S, Askola, J, Kärhä, P, Manoocheri, F & Ikonen, E 2017, ' Nonlinearity characterization of array spectroradiometers for the solar UV measurements ', Applied Optics, vol. 56, no. 11, 3077, pp. 3077-3086 . https://doi.org/10.1364/AO.56.003077
Array spectroradiometers are attractive alternatives to scanning spectroradiometers in solar ultraviolet measurements. However, the measurement of solar spectral irradiance imposes stringent requirements for the linearity of the instruments. In this
Autor:
Tomi Karppinen, Meelis-Mait Sildoja, Saulius Nevas, Joop Mes, Juha Karhu, Steffen Gross, Lionel Doppler, Erkki Ikonen, Anna Vaskuri, Petri Kärhä, Tomi Pulli, Kaisa Lakkala, Maksim Shpak, Farshid Manoocheri
Publikováno v:
Pulli, T, Karppinen, T, Nevas, S, Kärhä, P, Lakkala, K, Karhu, J M, Sildoja, M, Vaskuri, A, Shpak, M, Manoocheri, F, Doppler, L, Gross, S, Mes, J & Ikonen, E 2018, ' Out-of-Range Stray Light Characterization of Single-Monochromator Brewer Spectrophotometers ', Atmosphere-Ocean, vol. 56, no. 1, pp. 1-11 . https://doi.org/10.1080/07055900.2017.1419335
Stray light in single-monochromator Brewer instruments increases the uncertainty of solar ultraviolet spectral irradiance measurements and ozone retrievals. To study how spectral irradiance within and outside the measurement ranges of the instruments
Publikováno v:
PROCEEDINGS OF the 29th Quadrennial Session of the CIE.
Publikováno v:
Baumgartner, H, Renoux, D, Kärhä, P, Poikonen, T, Pulli, T & Ikonen, E 2016, ' Natural and accelerated ageing of LED lamps ', Lighting Research and Technology, vol. 48, no. 8, pp. 930-942 . https://doi.org/10.1177/1477153515603757
Five different types of LED lamps were aged for 35 months at room temperature and for six months at the temperatures of 45℃ and 60℃. The lifetimes for the lamps were predicted from the luminous flux measurement results. The long-term tests show t
Publikováno v:
Metrologia. 57:049501