A quartz enhanced photo-acoustic sensor employing a single-mode quantum cascade laser emitting at 3.93 Terahertz (THz) is reported. A custom tuning fork with a 1 mm spatial separation between the prongs allows the focusing of the THz laser beam between them, while preventing the prongs illumination. A methanol transition with line-strength of 4.28 × 10^−21 cm has been selected as target spectroscopic line. At a laser optical power of ∼ 40 μW, we reach a sensitivity of 7 parts per million in 4s integration time, corresponding to a 1σ normalized noise-equivalent absorption of 2 × 10^−10 cm^−1W/Hz½.
|Titolo:||Terahertz quartz enhanced photo-acoustic sensor|
|Data di pubblicazione:||2013|
|Digital Object Identifier (DOI):||10.1063/1.4812438|
|Appare nelle tipologie:||1.1 Articolo in rivista|