A5105821630- Advanced Fiber Laser Technologies
- Spectroscopy and Laser Applications
- Photonic and Optical Devices
- Laser-Matter Interactions and Applications
- Photonic Crystal and Fiber Optics
- Mass Spectrometry Techniques and Applications
- Advanced Fiber Optic Sensors
- Laser Design and Applications
- Analytical Chemistry and Sensors
- Spectroscopy Techniques in Biomedical and Chemical Research
- Solid State Laser Technologies
- Photorefractive and Nonlinear Optics
- Insect Pheromone Research and Control
- Advanced Chemical Sensor Technologies
- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Water Quality Monitoring and Analysis
- Advanced Measurement and Metrology Techniques
- Indoor Air Quality and Microbial Exposure
- Spectroscopy and Chemometric Analyses
- Semiconductor Lasers and Optical Devices
- Photoacoustic and Ultrasonic Imaging
- Phase Equilibria and Thermodynamics
- Stellar, planetary, and galactic studies
- Thermography and Photoacoustic Techniques
National Institute of Standards and Technology
2012-2023
University of Colorado Boulder
2010-2021
Physical Measurement Laboratory
2020
Laboratory for Atmospheric and Space Physics
2010
University of Arkansas at Fayetteville
2005
Spectroscopy in the molecular fingerprint spectral region (6.7–20 µm) yields critical information on material structure for physical, chemical, and biological sciences. Despite decades of interest effort, this portion electromagnetic spectrum remains challenging to cover with conventional laser technologies. In paper, we present a simple robust method generating super-octave, optical frequency combs through intra-pulse difference generation an orientation-patterned gallium phosphide crystal....
We describe and characterize a 25 GHz laser frequency comb based on cavity-filtered erbium fiber mode-locked laser. The provides uniform array of optical frequencies spanning 1450 nm to 1700 nm, is stabilized by use global positioning system referenced atomic clock. This was deployed at the 9.2 m Hobby-Eberly telescope McDonald Observatory where it used as radial velocity calibration source for fiber-fed Pathfinder near-infrared spectrograph. Stellar targets were observed in three echelle...
Using aluminum-nitride photonic-chip waveguides, we generate optical-frequency-comb supercontinuum spanning from 500 nm to 4000 with a 0.8 nJ seed pulse, and show that the spectrum can be tailored by changing waveguide geometry. Since aluminum nitride exhibits both quadratic cubic nonlinearities, spectra feature simultaneous contributions numerous nonlinear mechanisms: generation, difference-frequency second-harmonic third-harmonic generation. As one application of integrating multiple...
Mid-infrared femtosecond optical frequency combs were produced by difference generation of the spectral components a near-infrared comb in 3-mm-long MgO:PPLN crystal. We observe strong pump depletion and 9.3 dB parametric gain 1.5 μm signal, which yields powers above 500 mW (3 μW/mode) idler with spectra covering 2.8 to 3.5 μm. Potential for broadband, high-resolution molecular spectroscopy is demonstrated absorption interferograms obtained heterodyning two combs.
Abstract Optical frequency combs have revolutionized optical metrology and are being actively investigated in a number of applications outside pure metrology. For reasons cost, robustness, performance, flexibility, the erbium fiber laser comb has emerged as most commonly used system many different designs been demonstrated. We review approaches taken design combs, including major building blocks underlying mode-locked laser, amplifier, supercontinuum generation actuators for stabilization comb.
Open-path measurements of atmospheric gas species in the air, including volatile organic compounds, are essential to quantify emissions from sources like oil and gas, forest fires, industry. Here, we extend open-path dual-comb spectroscopy probe fundamental mid-infrared C-H stretch modes compounds over up 1 km long open-air paths. The spectrometer’s high resolution accuracy facilitates suppression strong spectral clutter water methane, allowing quantitative released acetone isopropanol with...
A 12.5 GHz-spaced optical frequency comb locked to a Global Positioning disciplined oscillator for near-IR spectrograph calibration is presented. The generated via filtering 250 MHz-spaced comb. Subsequency nonlinear broadening of the GHz extends wavelength range cover 1380 nm 1820 nm, providing complete coverage over H-band transmission widow Earth's atmosphere. Finite suppression spurious sidemodes, linewidth and instability have been examined estmiate potential biases in calibration....
Abstract Short duration, intense pulses of light can experience dramatic spectral broadening when propagating through lengths optical fibre. This continuum generation process is caused by a combination nonlinear effects including the formation dispersive waves. Optical analogues Cherenkov radiation, these waves allow pulse to radiate power into distant region. In this work, efficient and coherent wave visible ultraviolet demonstrated in silica waveguides on silicon chip. Unlike fibre...
Optical waveguides made from periodically poled materials provide high confinement of light and enable the generation new wavelengths via quasi-phase-matching, making them a key platform for nonlinear optics photonics. However, such devices are not typically employed high-harmonic generation. Here, using 200-fs, 10-nJ-level pulses 4100-nm at 1 MHz, we generate harmonics up to 13th harmonic (315 nm) in chirped, lithium niobate waveguide. Total conversion efficiencies into visible–ultraviolet...
The discovery and characterization of exoplanets around nearby stars is driven by profound scientific questions about the uniqueness Earth our Solar System, conditions under which life could exist elsewhere in Galaxy. Doppler spectroscopy, or radial velocity (RV) technique, has been used extensively to identify hundreds exoplanets, but with notable challenges detecting terrestrial mass planets orbiting within habitable zones. We describe infrared RV spectroscopy at 10 m Hobby-Eberly...
This manuscript describes the design of a robust, mid-infrared dual-comb spectrometer operating in 3.1-µm to 4-µm spectral window for future field applications. The represents an improvement system size, power consumption, and robustness relative previous work while also providing high signal-to-noise ratio. We demonstrate quality factor 2×106 30 hours continuous operation over 120-meter outdoor air path.
Abstract Open‐path dual‐comb spectroscopy provides multispecies atmospheric gas concentration measurements with high precision. Here, open‐path is extended to the mid‐infrared 5 µm window, enabling retrievals of primary greenhouse gases, N 2 O, CO , and H as well criteria air pollutants O 3 across 600 m km round‐trip paths. Measurements are demonstrated over a five‐day period at min temporal resolution 80% uptime. The achieved precision sufficient resolve variations multiple species;...
We present a high-resolution (R ~ 50 000) atlas of uranium-neon (U/Ne) hollow-cathode spectrum in the H-band (1454 nm to 1638 nm) for calibration near-infrared spectrographs. obtained this U/Ne simultaneously with laser-frequency comb spectrum, which we used provide first-order spectrum. then calibrated using recently-published uranium line list Redman et al. (2011), is derived from Fourier transform spectrometer measurements. These two independent calibrations allowed us easily identify...
We present a multibranch laser frequency comb based upon 250 MHz mode-locked erbium-doped fiber that spans more than 300 THz of bandwidth, from 660 nm to 2100 nm. Light Er:fiber is amplified and then broadened in highly-nonlinear produce substantial power at ∼1050 This light subsequently Yb:fiber 1.2 nJ, 73 fs pulses 1040 Extension the into visible achieved by supercontinuum generation light. Comb coherence verified with cascaded f-2f interferometry comparison stabilized laser.
We experimentally demonstrate a simple configuration for mid-infrared (MIR) frequency comb generation in quasi-phase-matched lithium niobate waveguides using the cascaded-χ(2) nonlinearity. With nanojoule-scale pulses from an Er:fiber laser, we observe octave-spanning supercontinuum near-infrared with dispersive wave 2.5-3 μm region and intrapulse difference 4-5 region. By engineering grating profiles, tunable, narrowband MIR broadband spectra are both observed this geometry. Finally,...
Si3N4 waveguides, pumped at 1550 nm, can provide spectrally smooth, broadband light for gas spectroscopy in the important 2 μm to 2.5 atmospheric water window, which is only partially accessible with silica-fiber based systems. By combining Er+ fiber frequency combs and supercontinuum generation tailored high signal-to-noise dual-comb spanning demonstrated. Acquired spectra of CO CO2 agree well database line shape models have a spectral-signal-to-noise as 48/√s, showing that coherence...
We present results from a field study monitoring methane and volatile organic compound emissions near an unconventional oil well development in Northern Colorado September 2019 to May 2020 using mid-infrared dual-comb spectrometer. This instrument allowed quantification of methane, ethane, propane single measurement with high time resolution integrated path sampling. Using ethane as tracer gases for gas activity, we observed during the drilling, hydraulic fracturing, millout, flowback phases...
A source of ultrashort pulses light in the 2 µm region was constructed using supercontinuum broadening from an erbium mode-locked laser.The output spectrum spanned 1000 nm to 2200 with average power 250 mW.A pulse width 39 fs for part 2000 region, corresponding less than six optical cycles, achieved.A heterodyne measurement free-running laser a narrow-linewidth continuous wave resulted near shot noise-limited beat note signal-to-noise ratio 45 dB 10 kHz resolution bandwidth.The relative...
Radial velocity (RV) surveys supported by high precision wavelength references (notably ThAr lamps and I2 cells) have successfully identified hundreds of exoplanets; however, as the search for exoplanets moves to cooler, lower mass stars, optimum wave band observation these objects into near infrared (NIR) new standards are required. To address this need we following up our successful deployment an H band(1.45-1.7μm) laser frequency comb based reference with a working in Y J bands...
An optical etalon illuminated by a white light source provides broadband comb-like spectrum that can be employed as calibration for astronomical spectrographs in radial velocity (RV) surveys extrasolar planets.For this application the frequency stability of is critical, its transmission susceptible to fluctuations due changes cavity temperature, power and input polarization.In paper we present laser comb measurement technique characterize custom-designed fiber Fabry-Pérot interferometer...
We present a scheme for generating super-octave, long-wave infrared combs in the molecular fingerprint region using intra-pulse difference frequency generation an orientation patterned GaP crystal. demonstrate high resolution dual-comb spectroscopy methanol vapor.