The Experts below are selected from a list of 221478 Experts worldwide ranked by ideXlab platform
Scott A Diddams - One of the best experts on this subject based on the ideXlab platform.
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Optical Frequency combs coherently uniting the electromagnetic spectrum
Science, 2020Co-Authors: Kerry J Vahala, Scott A Diddams, Thomas UdemAbstract:Optical Frequency combs were introduced around 20 years ago as a laser technology that could synthesize and count the ultrafast rate of the oscillating cycles of light. Functioning in a manner analogous to a clockwork of gears, the Frequency comb phase-coherently upconverts a radio Frequency signal by a factor of [Formula: see text] to provide a vast array of evenly spaced Optical frequencies, which is the comb for which the device is named. It also divides an Optical Frequency down to a radio Frequency, or translates its phase to any other Optical Frequency across hundreds of terahertz of bandwidth. We review the historical backdrop against which this powerful tool for coherently uniting the electromagnetic spectrum developed. Advances in Frequency comb functionality, physical implementation, and application are also described.
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Electro-Optical Frequency division and stable microwave synthesis
Nonlinear Optics, 2015Co-Authors: Hansuek Lee, Scott A Diddams, Kerry J VahalaAbstract:A new method of Optical Frequency division is demonstrated using a tunable electrical oscillator to create combs through phase modulation of a dual Brillouin laser Frequency reference. The method is used to generate stable microwaves.
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electro Optical Frequency division and stable microwave synthesis
Science, 2014Co-Authors: Hansuek Lee, Scott A Diddams, Kerry J VahalaAbstract:Optical Frequency division by using Frequency combs has revolutionized time keeping and the generation of stable microwave signals. We demonstrate Optical Frequency division and microwave generation by using a tunable electrical oscillator to create dual combs through phase modulation of two Optical signals that have a stable difference Frequency. Phase-locked control of the electrical oscillator by means of Optical Frequency division produces stable microwaves. Our approach transposes the oscillator and Frequency reference of a conventional microwave Frequency synthesizer. In this way, the oscillator experiences large phase noise reduction relative to the Frequency reference. The electro-Optical approach additionally relaxes the need for highly linear photodetection of the comb mode spacing. As well as simplicity, the technique is also tunable and scalable to higher division ratios.
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self injection locking and phase locked states in microresonator based Optical Frequency combs
Physical Review Letters, 2014Co-Authors: Pascal Delhaye, Scott B Papp, Katja Beha, Scott A DiddamsAbstract:: Microresonator-based Optical Frequency combs have been a topic of extensive research during the last few years. Several theoretical models for the comb generation have been proposed; however, they do not comprehensively address experimental results that show a variety of independent comb generation mechanisms. Here, we present Frequency-domain experiments that illuminate the transition of microcombs into phase-locked states, which show characteristics of injection locking between ensembles of comb modes. In addition, we demonstrate the existence of equidistant Optical Frequency combs that are phase stable but have nondeterministic phase relationships between individual comb modes.
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mechanical control of a microrod resonator Optical Frequency comb
Physical Review X, 2013Co-Authors: Scott B Papp, Pascal Delhaye, Scott A DiddamsAbstract:``Microcombs,'' Frequency combs based on Optical microcavities, are small in size and low in power consumption. They are seen as a very attractive alternative to traditional Optical Frequency combs based on tabletop lasers. Now, experimentalists advance the development of microcombs in two important ways: simplifying and speeding up their fabrication to just under one minute and stabilizing their Frequency spacing with a precision of $5\ifmmode\times\else\texttimes\fi{}{10}^{-15}$ by controlling cavity modes with mechanical strain.
Ronald Holzwarth - One of the best experts on this subject based on the ideXlab platform.
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Optical Frequency dissemination for metrology applications
Comptes Rendus Physique, 2015Co-Authors: Stefan Droste, Thomas Udem, Ronald Holzwarth, T W HanschAbstract:Abstract With the progress in the development of Optical Frequency standards grows the demand for the dissemination of stable Optical frequencies. To date, Optical fiber links constitute the most promising medium to bridge large geographical distances while still maintaining a high degree of Frequency stability and accuracy. We investigated the transfer of an Optical Frequency along different fiber links during the past years and achieved a fractional instability and uncertainty at a level lower than 10 − 19 using fiber links with lengths of up to almost 2000 km. We give an overview of different techniques and methods that can be used in combination with Optical fiber links to achieve a stable Frequency transfer. The results of different fiber links are summarized and an outlook of future links is given.
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Optical Frequency transfer via 1840 km fiber link with superior stability
Conference on Lasers and Electro-Optics, 2014Co-Authors: Stefan Droste, Thomas Udem, G Grosche, Katharina Predehl, H Schnatz, T W Hansch, F Ozimek, Ronald HolzwarthAbstract:We transferred an Optical Frequency along a 1840km fiber link and achieved an instability of 3x10^-15 at 1s with 4x10^-19 after 100s. The transferred Frequency shows no systematic offset within an uncertainty of 3x10^-19. Detailed analysis revealed a t^-2 response in the modified Allan deviation.
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Optical Frequency transfer via 1840 km fiber link with superior stability
International Frequency Control Symposium, 2014Co-Authors: Stefan Droste, Thomas Udem, G Grosche, Katharina Predehl, H Schnatz, T W Hansch, F Ozimek, Ronald HolzwarthAbstract:Optical Frequency transfer over a 1840 km fiber link is presented. The link is actively stabilized to deliver a Frequency with superior stability and accuracy. The spectral noise distribution of the stabilized link leads to an unprecedented fast averaging in the modified Allan deviation.
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Optical Frequency transfer over a single span 1840 km fiber link
Physical Review Letters, 2013Co-Authors: Stefan Droste, Thomas Udem, G Grosche, Katharina Predehl, H Schnatz, T W Hansch, F Ozimek, Ronald HolzwarthAbstract:: To compare the increasing number of Optical Frequency standards, highly stable Optical signals have to be transferred over continental distances. We demonstrate Optical-Frequency transfer over a 1840-km underground Optical fiber link using a single-span stabilization. The low inherent noise introduced by the fiber allows us to reach short term instabilities expressed as the modified Allan deviation of 2×10(-15) for a gate time τ of 1 s reaching 4×10(-19) in just 100 s. We find no systematic offset between the sent and transferred frequencies within the statistical uncertainty of about 3×10(-19). The spectral noise distribution of our fiber link at low Fourier frequencies leads to a τ(-2) slope in the modified Allan deviation, which is also derived theoretically.
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Optical Frequency transfer over a single span 1840 km fiber link
Physical Review Letters, 2013Co-Authors: Stefan Droste, Thomas Udem, G Grosche, Katharina Predehl, H Schnatz, T W Hansch, F Ozimek, Ronald HolzwarthAbstract:To compare the increasing number of Optical Frequency standards, highly stable Optical signals have to be transferred over continental distances. We demonstrate Optical-Frequency transfer over a 1840-km underground Optical fiber link using a single-span stabilization. The low inherent noise introduced by the fiber allows us to reach short term instabilities expressed as the modified Allan deviation of $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}15}$ for a gate time $\ensuremath{\tau}$ of 1 s reaching $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}19}$ in just 100 s. We find no systematic offset between the sent and transferred frequencies within the statistical uncertainty of about $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}19}$. The spectral noise distribution of our fiber link at low Fourier frequencies leads to a ${\ensuremath{\tau}}^{\ensuremath{-}2}$ slope in the modified Allan deviation, which is also derived theoretically.
Aleksandra Foltynowicz - One of the best experts on this subject based on the ideXlab platform.
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Optical Frequency comb photoacoustic spectroscopy
Physical Chemistry Chemical Physics, 2018Co-Authors: Ibrahim Sadiek, Tommi Mikkonen, Markku Vainio, Juha Toivonen, Aleksandra FoltynowiczAbstract:We report the first photoacoustic detection scheme using an Optical Frequency comb-Optical Frequency comb photoacoustic spectroscopy (OFC-PAS). OFC-PAS combines the broad spectral coverage and the high resolution of OFCs with the small sample volume of cantilever-enhanced PA detection. In OFC-PAS, a Fourier transform spectrometer (FTS) is used to modulate the intensity of the exciting comb source at a Frequency determined by its scanning speed. One of the FTS outputs is directed to the PA cell and the other is measured simultaneously with a photodiode and used to normalize the PA signal. The cantilever-enhanced PA detector operates in a non-resonant mode, enabling detection of a broadband Frequency response. The broadband and the high-resolution capabilities of OFC-PAS are demonstrated by measuring the rovibrational spectra of the fundamental C-H stretch band of CH4, with no instrumental line shape distortions, at total pressures of 1000 mbar, 650 mbar, and 400 mbar. In this first demonstration, a spectral resolution two orders of magnitude better than previously reported with broadband PAS is obtained, limited by the pressure broadening. A limit of detection of 0.8 ppm of methane in N2 is accomplished in a single interferogram measurement (200 s measurement time, 1000 MHz spectral resolution, 1000 mbar total pressure) for an exciting power spectral density of 42 μW/cm-1. A normalized noise equivalent absorption of 8 × 10-10 W cm-1 Hz-1/2 is obtained, which is only a factor of three higher than the best reported with PAS based on continuous wave lasers. A wide dynamic range of up to four orders of magnitude and a very good linearity (limited by the Beer-Lambert law) over two orders of magnitude are realized. OFC-PAS extends the capability of Optical sensors for multispecies trace gas analysis in small sample volumes with high resolution and selectivity.
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Optical Frequency comb photoacoustic spectroscopy
arXiv: Optics, 2018Co-Authors: Ibrahim Sadiek, Tommi Mikkonen, Markku Vainio, Juha Toivonen, Aleksandra FoltynowiczAbstract:We report the first photoacoustic detection scheme using an Optical Frequency comb - the Optical Frequency comb photoacoustic spectroscopy (OFC-PAS). OFC-PAS combines the broad spectral coverage and the high resolution of OFCs with the small sample volume of cantilever-enhanced PA detection. In OFC-PAS, a Fourier transform spectrometer (FTS) is used to modulate the intensity of the exciting comb source at a Frequency determined by its scanning speed. One of the FTS outputs is directed to the PA cell and the other is measured simultaneously with a photodiode and used to normalize the PA signal. The cantilever-enhanced PA detector operates in a non-resonant mode, enabling detection of broadband Frequency response. The broadband and the high-resolution capabilities of OFC-PAS are demonstrated by measuring the rovibrational spectra of the fundamental C-H stretch band of CH${_4}$, with no instrumental line shape distortions, at total pressures of 1000 mbar, 650 mbar, and 400 mbar. In this first demonstration, a spectral resolution two orders of magnitude higher than previously reported with broadband PAS is obtained, limited by the pressure broadening. A limit of detection of 0.8 ppm of methane in N${_2}$ is accomplished in a single interferogram measurement (200 s measurement time, 1000 MHz resolution, 1000 mbar total pressure) for an exciting power spectral density of 42 {\mu}W/cm${^{-1}}$. A normalized noise equivalent absorption of 8x10${^{-10}}$ W cm${^{-1}}$ Hz${^{-1/2}}$ is obtained, which is only a factor of three higher than the best reported with PAS based on continuous wave lasers. A wide dynamic range of up to four orders of magnitude and a very good linearity (limited by the Beer-Lambert law) over two orders of magnitude are realized. OFC-PAS extends the capability of Optical sensors for multispecies trace gas analysis in small sample volume with high resolution and selectivity.
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Optical Frequency comb Faraday rotation spectroscopy
Applied Physics B, 2018Co-Authors: Alexandra C. Johansson, Jonas Westberg, Gerard Wysocki, Aleksandra FoltynowiczAbstract:We demonstrate Optical Frequency comb Faraday rotation spectroscopy (OFC-FRS) for broadband interference-free detection of paramagnetic species. The system is based on a femtosecond doubly resonant Optical parametric oscillator and a fast-scanning Fourier transform spectrometer (FTS). The sample is placed in a DC magnetic field parallel to the light propagation. Efficient background suppression is implemented via switching the direction of the field on consecutive FTS scans and subtracting the consecutive spectra, which enables long-term averaging. In this first demonstration, we measure the entire Q- and R-branches of the fundamental band of nitric oxide in the 5.2–5.4 µm range and achieve good agreement with a theoretical model.
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Optical Frequency Comb Faraday Rotation Spectroscopy
Conference on Lasers and Electro-Optics, 2018Co-Authors: Alexandra C. Johansson, Jonas Westberg, Gerard Wysocki, Aleksandra FoltynowiczAbstract:By combining Faraday rotation spectroscopy with an Optical Frequency comb Fourier transform spectrometer, we measure background- and calibration-free spectra of the entire Q- and R-branches of the fundamental band of nitric oxide at 1850-1920 cm−1.
H Schnatz - One of the best experts on this subject based on the ideXlab platform.
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Optical Frequency transfer via 1840 km fiber link with superior stability
Conference on Lasers and Electro-Optics, 2014Co-Authors: Stefan Droste, Thomas Udem, G Grosche, Katharina Predehl, H Schnatz, T W Hansch, F Ozimek, Ronald HolzwarthAbstract:We transferred an Optical Frequency along a 1840km fiber link and achieved an instability of 3x10^-15 at 1s with 4x10^-19 after 100s. The transferred Frequency shows no systematic offset within an uncertainty of 3x10^-19. Detailed analysis revealed a t^-2 response in the modified Allan deviation.
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Optical Frequency transfer via 1840 km fiber link with superior stability
International Frequency Control Symposium, 2014Co-Authors: Stefan Droste, Thomas Udem, G Grosche, Katharina Predehl, H Schnatz, T W Hansch, F Ozimek, Ronald HolzwarthAbstract:Optical Frequency transfer over a 1840 km fiber link is presented. The link is actively stabilized to deliver a Frequency with superior stability and accuracy. The spectral noise distribution of the stabilized link leads to an unprecedented fast averaging in the modified Allan deviation.
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Optical Frequency transfer over a single span 1840 km fiber link
Physical Review Letters, 2013Co-Authors: Stefan Droste, Thomas Udem, G Grosche, Katharina Predehl, H Schnatz, T W Hansch, F Ozimek, Ronald HolzwarthAbstract:: To compare the increasing number of Optical Frequency standards, highly stable Optical signals have to be transferred over continental distances. We demonstrate Optical-Frequency transfer over a 1840-km underground Optical fiber link using a single-span stabilization. The low inherent noise introduced by the fiber allows us to reach short term instabilities expressed as the modified Allan deviation of 2×10(-15) for a gate time τ of 1 s reaching 4×10(-19) in just 100 s. We find no systematic offset between the sent and transferred frequencies within the statistical uncertainty of about 3×10(-19). The spectral noise distribution of our fiber link at low Fourier frequencies leads to a τ(-2) slope in the modified Allan deviation, which is also derived theoretically.
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Optical Frequency transfer over a single span 1840 km fiber link
Physical Review Letters, 2013Co-Authors: Stefan Droste, Thomas Udem, G Grosche, Katharina Predehl, H Schnatz, T W Hansch, F Ozimek, Ronald HolzwarthAbstract:To compare the increasing number of Optical Frequency standards, highly stable Optical signals have to be transferred over continental distances. We demonstrate Optical-Frequency transfer over a 1840-km underground Optical fiber link using a single-span stabilization. The low inherent noise introduced by the fiber allows us to reach short term instabilities expressed as the modified Allan deviation of $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}15}$ for a gate time $\ensuremath{\tau}$ of 1 s reaching $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}19}$ in just 100 s. We find no systematic offset between the sent and transferred frequencies within the statistical uncertainty of about $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}19}$. The spectral noise distribution of our fiber link at low Fourier frequencies leads to a ${\ensuremath{\tau}}^{\ensuremath{-}2}$ slope in the modified Allan deviation, which is also derived theoretically.
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Optical Frequency transfer via 146 km fiber link with 10 19 relative accuracy
Optics Letters, 2009Co-Authors: G Grosche, Osama Terra, Katharina Predehl, Ronald Holzwarth, B Lipphardt, F Vogt, U Sterr, H SchnatzAbstract:We demonstrate the long-distance transmission of an ultrastable Optical Frequency derived directly from a state-of-the-art Optical Frequency standard. Using an active stabilization system we deliver the Frequency via a 146-km-long underground fiber link with a fractional instability of 3×10−15 at 1 s, which is close to the theoretical limit for our transfer experiment. After 30,000 s, the relative uncertainty for the transfer is at the level of 1×10−19. Tests with a very short fiber show that noise in our stabilization system contributes fluctuations that are 2 orders of magnitude lower, namely, 3×10−17 at 1 s, reaching 10−20 after 4000 s.
Pascal Delhaye - One of the best experts on this subject based on the ideXlab platform.
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self injection locking and phase locked states in microresonator based Optical Frequency combs
Physical Review Letters, 2014Co-Authors: Pascal Delhaye, Scott B Papp, Katja Beha, Scott A DiddamsAbstract:: Microresonator-based Optical Frequency combs have been a topic of extensive research during the last few years. Several theoretical models for the comb generation have been proposed; however, they do not comprehensively address experimental results that show a variety of independent comb generation mechanisms. Here, we present Frequency-domain experiments that illuminate the transition of microcombs into phase-locked states, which show characteristics of injection locking between ensembles of comb modes. In addition, we demonstrate the existence of equidistant Optical Frequency combs that are phase stable but have nondeterministic phase relationships between individual comb modes.
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mechanical control of a microrod resonator Optical Frequency comb
Physical Review X, 2013Co-Authors: Scott B Papp, Pascal Delhaye, Scott A DiddamsAbstract:``Microcombs,'' Frequency combs based on Optical microcavities, are small in size and low in power consumption. They are seen as a very attractive alternative to traditional Optical Frequency combs based on tabletop lasers. Now, experimentalists advance the development of microcombs in two important ways: simplifying and speeding up their fabrication to just under one minute and stabilizing their Frequency spacing with a precision of $5\ifmmode\times\else\texttimes\fi{}{10}^{-15}$ by controlling cavity modes with mechanical strain.
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mechanical control of a microrod resonator Optical Frequency comb
arXiv: Optics, 2012Co-Authors: Scott B Papp, Pascal Delhaye, Scott A DiddamsAbstract:Robust control and stabilization of Optical Frequency combs enables an extraordinary range of scientific and technological applications, including Frequency metrology at extreme levels of precision, novel spectroscopy of quantum gases and of molecules from visible wavelengths to the far infrared, searches for exoplanets, and photonic waveform synthesis. Here we report on the stabilization of a microresonator-based Optical comb (microcomb) by way of mechanical actuation. This represents an important step in the development of microcomb technology, which offers a pathway toward fully-integrated comb systems. Residual fluctuations of our 32.6 GHz microcomb line spacing reach a record stability level of $5\times10^{-15}$ for 1 s averaging, thereby highlighting the potential of microcombs to support modern Optical Frequency standards. Furthermore, measurements of the line spacing with respect to an independent Frequency reference reveal the effective stabilization of different spectral slices of the comb with a $<$0.5 mHz variation among 140 comb lines spanning 4.5 THz. These experiments were performed with newly-developed microrod resonators, which were fabricated using a CO$_2$-laser-machining technique.
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full stabilization of a microresonator based Optical Frequency comb
Physical Review Letters, 2008Co-Authors: Pascal Delhaye, Albert Schliesser, Olivier Arcizet, Ronald Holzwarth, Tobias J KippenbergAbstract:We demonstrate control and stabilization of an Optical Frequency comb generated by four-wave mixing in a monolithic microresonator with a mode spacing in the microwave regime (86 GHz). The comb parameters (mode spacing and offset Frequency) are controlled via the power and the Frequency of the pump laser, which constitutes one of the comb modes. Furthermore, generation of a microwave beat note at the comb's mode spacing Frequency is demonstrated, enabling direct stabilization to a microwave Frequency standard.
