اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدHigh-precision methanol spectroscopy with a widely tunable SI-traceable frequency-comb-based mid-infrared QCL
99
0
0.0
(
0
)
تأليف
R. Santagata
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
There is an increasing demand for precise molecular spectroscopy, in particular in the mid-infrared fingerprint window that hosts a considerable number of vibrational signatures, whether it be for modeling our atmosphere, interpreting astrophysical spectra or testing fundamental physics. We present a high-resolution mid-infrared spectrometer traceable to primary frequency standards. It combines a widely tunable ultra-narrow Quantum Cascade Laser (QCL), an optical frequency comb and a compact multipass cell. The QCL frequency is stabilized onto a comb controlled with a remote near-infrared ultra-stable laser, transferred through a fiber link. The resulting QCL frequency stability is below 10-15 from 0.1 to 10s and its frequency uncertainty of 4x10-14 is given by the remote frequency standards. Continuous tuning over ~400 MHz is reported. We use the apparatus to perform saturated absorption spectroscopy of methanol in the low-pressure multipass cell and demonstrate a statistical uncertainty at the kHz level on transition center frequencies, confirming its potential for driving the next generation technology required for precise spectroscopic measurements.
قيم البحث
اقرأ أيضاً
Spectroscopy is a powerful tool for studying molecules and is commonly performed on large thermal molecular ensembles that are perturbed by motional shifts and interactions with the environment and one another, resulting in convoluted spectra and lim
ited resolution. Here, we use generally applicable quantum-logic techniques to prepare a trapped molecular ion in a single quantum state, drive terahertz rotational transitions with an optical frequency comb, and read out the final state non-destructively, leaving the molecule ready for further manipulation. We resolve rotational transitions to 11 significant digits and derive the rotational constant of CaH+ to be B_R = 142501777.9(1.7) kHz. Our approach suits a wide range of molecular ions, including polyatomics and species relevant for tests of fundamental physics, chemistry, and astrophysics.
We present a new method for accurate mid-infrared frequency measurements and stabilization to a near-infrared ultra-stable frequency reference, transmitted with a long-distance fibre link and continuously monitored against state-of-the-art atomic fou
ntain clocks. As a first application, we measure the frequency of an OsO4 rovibrational molecular line around 10 $mu$m with a state-of-the-art uncertainty of 8x10-13. We also demonstrate the frequency stabilization of a mid-infrared laser with fractional stability better than 4x10-14 at 1 s averaging time and a line-width below 17 Hz. This new stabilization scheme gives us the ability to transfer frequency stability in the range of 10-15 or even better, currently accessible in the near-infrared or in the visible, to mid-infrared lasers in a wide frequency range.
Dual-comb spectroscopy has been proven a powerful tool in molecular characterization, which remains challenging to implement in the mid-infrared (MIR) region due to difficulties in the realization of two mutually locked comb sources and efficient pho
todetection. An effective way to overcome those limitations is optical upconversion; however, previously reported configurations are either demanding or inefficient. Here we introduce and experimentally demonstrate a variant of dual-comb spectroscopy called cross-comb spectroscopy, in which a MIR comb is upconverted via sum-frequency generation (SFG) with a near-infrared (NIR) comb with a shifted repetition rate and then interfered with a spectral extension of the NIR comb. We experimentally demonstrate a proof-of-concept measurement of atmospheric CO2 around 4.25 micrometer, with a 350-nm instantaneous bandwidth and 25000 resolved comb lines. Cross-comb spectroscopy can be realized using up- or down-conversion and offers an adaptable and efficient alternative to dual-comb spectroscopy outside the well-developed near-IR region, where having two mutually coherent sources and efficient photodetection is challenging. Moreover, the nonlinear gating in cross-comb spectroscopy promises a superior dynamic range compared to dual-comb spectroscopy.
We have built a frequency chain which enables to measure the absolute frequency of a laser emitting in the 28-31 THz frequency range and stabilized onto a molecular absorption line. The set-up uses an optical frequency comb and an ultrastable 1.55 $m
u$m frequency reference signal, transferred from LNE-SYRTE to LPL through an optical link. We are now progressing towards the stabilization of the mid-IR laser via the frequency comb and the extension of this technique to quantum cascade lasers. Such a development is very challenging for ultrahigh resolution molecular spectroscopy and fundamental tests of physics with molecules.
We examine a range of effects arising from ac magnetic fields in high precision metrology. These results are directly relevant to high precision measurements, and accuracy assessments for state-of-the-art optical clocks. Strategies to characterize th
ese effects are discussed and a simple technique to accurately determine trap-induced ac magnetic fields in a linear Paul trap is demonstrated using $^{171}mathrm{Yb}^+$
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
