Zobrazeno 1 - 10
of 53
pro vyhledávání: '"Karhu, Juho"'
Autor:
Karhu, Juho, Hieta, Tuomas
A real time trace gas detector for benzene is demonstrated. The measurement system takes an advantage of modest enrichment through short adsorption periods to reach a ppt-level detection limit with a sampling cycle of 90 s, which includes sample adso
Externí odkaz:
http://arxiv.org/abs/2202.08598
Photoacoustic detection is a sensitive method for measurement of light-absorbing particles directly in the aerosol phase. In this article, we demonstrate a new sensitive technique for photoacoustic aerosol absorption measurements using a cantilever m
Externí odkaz:
http://arxiv.org/abs/2106.12389
A high-sensitivity LED based photoacoustic NO$_2$ sensor is demonstrated. Sensitive photoacoustic gas sensors based on incoherent light sources are typically limited by background noise and drifts due to a strong signal generated by light absorbed at
Externí odkaz:
http://arxiv.org/abs/2104.11328
We demonstrate efficient generation of mid-infrared frequency combs based on continuous-wave-seeded femtosecond optical parametric generation in nonlinear waveguides. Conversion of the near-infrared pump to signal and idler light takes place with ver
Externí odkaz:
http://arxiv.org/abs/2104.05318
We present a simple method for fully-stabilized mid-infrared optical frequency comb generation based on single-pass femtosecond optical parametric generation that is seeded by a continuous-wave laser. We have implemented the method in a periodically
Externí odkaz:
http://arxiv.org/abs/2010.09423
Autor:
Larnimaa, Santeri, Halonen, Lauri, Karhu, Juho, Tomberg, Teemu, Metsälä, Markus, Genoud, Guillaume, Hieta, Tuomas, Bell, Steven, Vainio, Markku
We present the first high-resolution measurements and rotational analysis of the fundamental asymmetric stretching vibrational band ${\nu_3}(F_2)$ of radiocarbon methane. A spectrometer consisting of a mid-infrared continuous-wave optical parametric
Externí odkaz:
http://arxiv.org/abs/2004.07518
Autor:
Karhu, Juho, Tomberg, Teemu, Vieira, Francisco Senna, Genoud, Guillaume, Hänninen, Vesa, Vainio, Markku, Metsälä, Markus, Hieta, Tuomas, Bell, Steven, Halonen, Lauri
Publikováno v:
Opt. Lett. 44, 1142-1145 (2019)
We report a photoacoustic spectroscopy setup with a high-power mid-infrared frequency comb as the light source. The setup is used in broadband spectroscopy of radiocarbon methane. Due to the high sensitivity of a cantilever-enhanced photoacoustic cel
Externí odkaz:
http://arxiv.org/abs/1901.03154
Publikováno v:
In Photoacoustics February 2023 29
Autor:
Vainio, Markku, Karhu, Juho
A fully stabilized mid-infrared optical frequency comb spanning from 2.9 to 3.4 um is described. The comb is based on half-harmonic generation in a femtosecond optical parametric oscillator, which transfers the high phase coherence of a fully stabili
Externí odkaz:
http://arxiv.org/abs/1612.08647
Publikováno v:
EPJ Web of Conferences, Vol 255, p 11002 (2021)
We present an efficient method for generating frequency combs in the mid-infrared (MIR) spectral range in bulk lithium niobate crystals as well as in waveguides. Our approach is simple and robust, since it is based on single-pass configuration of fem
Externí odkaz:
https://doaj.org/article/b4651c5b563e44b2bdde559c201555a0