In this letter, we present a method of performing broadband midinfrared spectroscopy with conventional, freerunning, continuous wave fabryperot quantum cascade lasers fpqcls. The main advantages of this multi heterodyne spectroscopy mhs technique are fast acquisition rates, broad spectral coverage, high resolution, and solid state operation11. The resulting ofcs contained up to 50 unique frequency components and spanned more than 200 ghz. The laser was fibre coupled pdld blue box supplied by laser 2000, with an operating wavelength of 785 nm, with 500 mw of output power. Standoff detection from diffusely scattering surfaces. Multiheterodyne spectroscopy using interband cascade lasers. In this paper, we propose a model for an intuitive understanding of the performance of acoustooptic. The sample transmission spectrum probed by one multi mode fpqcl is downconverted to the radiofrequency domain through an. These techniques are viable even when the relative linewidth exceeds the repetition rate difference and can tremendously. Coherent multiheterodyne spectroscopy using stabilized optical frequency combs. The interference of the probing femtosecond laser with the diode lasers produces multi heterodyne beats in the radio frequency domain, which are captured using a highspeed photodetector and electronically processed to identify the absorption lines of interest with a combmode spectral resolution. Terahertz multiheterodyne spectroscopy using laser.
Multiheterodyne spectroscopic techniques using fabryperot. Heterodyne spectroscopy also falls into this category, but we will delay discussing it until we reach the submillimeter bolometrically, in which the number of charge carriers generated when a photon is absorbed in the detector, or the energy of that photon, are sensed. In crds, a highfinesse resonator is excited by an input beam that terminates abruptly. Presented at the 8th international conference on advanced vibrational spectroscopy icavs 8, vienna, austria, july 1217, 2015 talk tu806. The multi heterodyne spectrum exhibits 95 equally spaced frequency comb lines, indicating that the shortwave qcl combs are ideal candidates for highspeed highresolution spectroscopy. This work was partially supported by the national science foundation grant nos. Optical multi dimensional coherent spectroscopy is a powerful technique for studying the structure, properties and ultrafast dynamics of atoms, molecules, semiconductor materials and complex systems. Heterodyne spectroscopy also falls into this category, but we will delay discussing it until we reach the. Multiheterodyne spectroscopic techniques using fabry.
Coherent, multi heterodyne spectroscopy using stabilized optical frequency combs ian coddington, william c. Pdf optical heterodyne herriotttype multipass laser. The multi heterodyne signal from the detector provides only the difference or relative optical frequency between ofc1 and ofc2. Technical note on heterodyne detection in optical communications pdf report. Figure 2a shows a schematic of the principle of dualcomb spectroscopy.
It comprises a rapidly swept optical cavity in a singleended. Scientific solutions spatial heterodyne spectrometer. The measurement method is based on multiheterodyne downconversion of optical signals. Hodges2 1physical measurement laboratory, national institute of standards and technology, boulder, co 80305 3material measurement laboratory, national institute of standards and technology, gaithersburg, md 20899. Coherent multiheterodyne spectroscopy using acoustooptic. Coherent multiheterodyne spectroscopy using acoustooptic frequency combs. Rapidly swept, continuouswave cavity ringdown spectroscopy. Coherent multiheterodyne spectroscopy using acoustooptic frequency combs v. Heterodyne spectroscopy also falls into this category, but we will delay discussing it until we reach the submillimeter regime in chapter 8. The pairs of modes from both lasers creating heterodyne beat notes within the detector bandwidth are labeled with integers for identification, and the corresponding rf beat notes are shown in the inset. The key feature of our optical arrangement, presented in fig.
Final report compact multipollutant midinfrared laser. Two fabryperot quantum cascade lasers fpqcls are used in a differential dual comb configuration to perform swept multiheterodyne dispersion spectroscopy of low pressure nitrous oxide at khz. Sanders at the university of wisconsinmadison in order to measure ultraviolet spectra, an instrumentation method must be carefully selected. Bolometrically, in which the number of charge carriers generated when a photon is absorbed in. Based on extensive tests of five laser technologies ecqcl and distributed feedback dfbqcl in year 1, distributed bragg reflector dbrqcl in year 2, fabry perot fpqcls and a prototype multi dfbqcl array in year 3, we concluded that the most promising technology for benzene detection is the multi dfbqcl array. Broadband highresolution multi heterodyne rovibrational spectroscopy of gases with quantumand interband cascade lasers.
Michael angel, miniature spatial heterodyne spectrometer for remote laser induced breakdown and raman spectroscopy using fresnel collection optics, spectrochimica acta part b. Compared with direct absorption spectroscopy, the signaltonoise ratio is improved nearly one magnitude of factor by combining with the optical heterodyne. Coherent, multiheterodyne spectroscopy using stabilized optical. A further improvement is obtained by designing the multi heterodyne spectroscopy assembly to be selfcalibrating. Xiongs team to perform heterodyne 2d and 3d sfg spectroscopy. Optical heterodyne detection is a method of extracting information encoded as modulation of the phase, frequency or both of electromagnetic radiation in the wavelength band of visible or infrared light. Shortwave quantum cascade laser frequency comb for multi. Highresolution multiheterodyne spectroscopy based on fabry. Preamplification removes the overriding constraint of low signal loss for spectral processing, allowing flexible and powerful signal analysis. Cloud state university edwin mierkiewicz university of wisconsin. In contrast, multiheterodyne spectroscopy based on two frequency combs 9,10, also known as dualcomb spectroscopy, offers an elegant way.
Standoff detection from diffusely scattering surfaces using. Simple changes to the modulation frequency allowed for agile control of the comb spacing. The probe and homodyne oke signals can be filtered out, leaving the heterodyne frequency signal for detection. Newbury national institute for standards and technology the broadband, coherent nature of narrowlinewidth fiber frequency combs is exploited to measure the full. Absolute distance measurement by dualcomb interferometry. Correction of phase distortion in spatial heterodyne spectroscopy christoph r. While midinfrared radiation can be used to identify and quantify numerous chemical species, contemporary broadband midinfrared spectroscopic systems are often hindered by large footprints, moving parts, and high power consumption. Recent developments in multiheterodyne spectroscopy with multimode fabryperot fp lasers have enabled significant progress towards broadband highresolution spectroscopic sensing applications in the midinfrared. It comprises a rapidly swept optical cavity in a singleended optical. Recent developments in multi heterodyne spectroscopy with multi mode fabryperot fp lasers have enabled significant progress towards broadband highresolution spectroscopic sensing applications in the midinfrared.
The proposal is demonstrated by measuring the spectra of water vapor molecule in the region from 12247. These ofcs were then utilized for broadband, multiheterodyne. Highresolution multiheterodyne spectroscopy based on. Dualdrive machzehnder modulators were utilized to produce powerleveled optical frequency combs ofcs from a continuouswave laser. On the other hand, multiheterodyne spectroscopy based on two frequency combs 6, 7, also known as dual comb spec troscopy, offers an elegant way of. Fred roesler university of wisconsin john harlander st. Reynolds university of wisconsin kurt jaehnig university of wisconsin. Optical multidimensional coherent spectroscopy is a powerful technique for studying the structure, properties and ultrafast dynamics of atoms, molecules, semiconductor materials and. The light signal is compared with standard or reference light from a local oscillator lo that would have a fixed offset in frequency and phase from the signal if the latter carried null. Coherent multiheterodyne spectroscopy using stabilized optical. The single pair of ofcs emit over the optical spectral region of interest and due to. Multiheterodyne spectra of marginally stable combs. Lockindetection dualcomb spectroscopy hidenori koresawa et aldualcomb ranging zebin zhu and guanhao wuabsolute distance measurement by multi heterodyne interferometry using an electrooptic triple comb xianyu zhao et althis content was downloaded from ip address 157. Wysocki, multiheterodyne spectroscopic techniques using fabryperot quantum cascade lasers for trace gas detection, in conference on lasers and electrooptics, osa technical digest 2016 optical society of america, 2016, paper sth4j.
A further improvement is obtained by designing the multiheterodyne spectroscopy assembly to be selfcalibrating. The sample transmission spectrum probed by one multimode fpqcl is downconverted to the radiofrequency. Coherent, multiheterodyne spectroscopy using stabilized optical frequency combs ian coddington, william c. An overview of spatial heterodyne spectroscopy principle oii shs participants. Coherent multiheterodyne spectroscopy using stabilized. Wysocki, midinfrared quantum cascade laserbased multi heterodyne spectroscopy of small and large molecules in gasphase, in flair 2016 field laser applications in industry and research, 5 th edition of international conference, aixlesbains, france, september 1216 2016. The interference of the probing femtosecond laser with the diode lasers produces multiheterodyne beats in the radio frequency domain, which are captured using a highspeed photodetector and electronically processed to identify the absorption lines of interest with a combmode spectral resolution. Renata bartula under the supervision of associate professor scott t. The laser engine of the entire system is the coherent astrella ultrafast amplifier.
To investigate the applicability of the results of ref. Correction of phase distortion in spatial heterodyne. David burghoff, yang yang, and qing hu, computationallyassisted multiheterodyne spectroscopy, u. Multiheterodyne spectroscopy using multifrequency combs.
A multiband spatial heterodyne spectrometer for determining spectra in first and second wavelength bands has a beam splitter configured to split incident light and to direct the incident light upon a first and a second diffraction grating. They combine many advantages for multi heterodyne interferometry and dualcomb spectroscopy. Roesler the detailed analysis of measured interferograms generally requires phase correction. Research project publication details compact multi. The potential of irheterodyne spectroscopy springerlink.
We demonstrate that it is possible to extract the phase and timing signals of a multiheterodyne spectrum completely computationally, without any extra measurements or optical elements. Df, respectively, where df is the difference in the comb line spacings. Publications quantum and nonlinear optoelectronics group. The gratings are configured for littrow reflection of incident light of the first wavelength band at a first order and littrow reflection of incident light. Fleming department of chemistr y and qb3 histitute universit y of cahfomia, berkeley and physical bioscience s division, lawrenc e berkele y nationa l laboratory, berkeley, california 94720 email. Noiseimmune cavityenhanced opticalheterodyne molecular spectroscopy however, all attempts to directly combine ceas with a locking approach dceas have one thing in common. The technique is based on a multiheterodyne beating of two frequency combs with slightly different comb line spacings f rep,1 and f rep,2. Multidimensional sfg spectroscopy the combination of high pulse energy and long term stability from a coherent astrella. Terahertz multiheterodyne spectroscopy using laser frequency combs yang yang 1,y, david burgho, darren j. Hodges2 1physical measurement laboratory, national institute of standards and technology, boulder, co 80305. We determine the absolute optical frequency by characterizing each ofc individually in an ftir spectrometer. For this, the two frequency combs are split and caused to beat twice on two different photodetectors. A sample to be examined is then only introduced into one of the beat branches.
Design and development of multipixel heterodyne instruments. Our cavity ringdown spectrometer incorporates continuouswave cw tunable diode lasers, fibreoptic coupling and standard photonics and optical telecommunications components. Spatial heterodyne spectrometer for transmissionraman. Finally, we show that with proper signal processing, it is possible to extend the multi heterodyne spectroscopy to quantum cascade laser combs operating in pulsed mode, greatly expanding the range. Twodimensional optical heterodyne spectroscopy of molecular. Computationally assisted multiheterodyne spectroscopy, filed 8 september 2016. Optical frequency combs of multighz linespacing for. Multiheterodyne two dimensional coherent spectroscopy using. Multiheterodyne spectroscopy using multifrequency combs david f. Based on extensive tests of five laser technologies ecqcl and distributed feedback dfbqcl in year 1, distributed bragg reflector dbrqcl in year 2, fabry perot fpqcls and a prototype multidfbqcl array in year 3, we concluded that the most promising technology. The probe and homodyne oke signals can be filtered. Twodimensional optical heterodyne spectroscopy of molecular complexes igor stiopkin, tobias brixner and graham r. They combine many advantages for multiheterodyne interferometry and dualcomb spectroscopy.
Dual comb spectroscopy allows for highresolution spectra to be measured over broad bandwidths, but an essential requirement for coherent integration is the availability of a phase reference. The challenge in realizing the full potential of multi heterodyne spectroscopy lies in achieving a narrow relative linewidth i. Instrumentation for absorption spectroscopy measurements in the ultraviolet. The shs does not require scanning to function at its full resolving power. In optical kerr effect oke spectroscopy, optical heterodyning of the oke signal and a small part of the probe signal produces a mixed signal consisting of probe, heterodyne okeprobe and homodyne oke signal. Laser absorption spectrometry las refers to techniques that use lasers to assess the concentration or amount of a species in gas phase by absorption spectrometry as optical spectroscopic techniques in general, and laserbased techniques in particular, have a great potential for detection and monitoring of constituents in gas phase. Xiong summarizes, 2d sfg with heterodyne detection is able to resolve homogeneous and inhomogeneous dynamics, and molecular orientation on molecular submonolayers, including airwater interfaces, electrode surfaces, and surface. Multiheterodyne two dimensional coherent spectroscopy. Newbury, coherent multiheterodyne spectroscopy using stabilized optical frequency combs, phys. Infrared heterodyne spectroscopy in astronomy albert betz department of physics university of california, berkeley summary a heterodyne spectrometer has been constructed and applied to problems in. Dualcomb spectroscopy based on quantumcascadelaser. In a first set of experiments, we demonstrate self heterodyne interferometry 28, 30 for measuring the transmission peaks of a fabryperot cavity with a submhz resolution. Spectroscopic sensing of gases can be performed with high sensitivity and photometric precision by cavity ringdown crd absorption spectroscopy. Good agreement between experimental results and numerical analysis is obtained.
Figure 1d shows the emission spectrum of the icls measured by fourier transform spectroscopy with a resolution of 0. The main advantages of this multiheterodyne spectroscopy mhs technique are fast acquisition rates, broad spectral coverage, high resolution, and solid state operation11. This linewidth must, at a minimum, be less than f ror the simple rf heterodyne comb of fig. Terahertz multiheterodyne spectroscopy using laser frequency combs.
We measure the absorption and phase shift experienced by each of 155 000 individual frequencycomb lines, spaced by 100 mhz and spanning from 1495 to 1620 nm, after passing through hydrogen cyanide gas. Dualcomb spectroscopy using electroopticmodulatorbased frequency combs broadened. Fourier transform infrared spectroscopy ftir is a popular technique for broadband spectral analysis in the midir. Direct comb multiheterodyne interference spectroscopy drntu. Osa multiheterodyne spectroscopy with optical frequency. Pdf multiheterodyne dispersion spectroscopy using fabry. Standoff spatial heterodyne raman spectrometer for. The spatial heterodyne spectrometer shs combines the high resolution and throughput of conventional interferometers with extreme robustness.
Reno4, and qing hu1 1department of electrical engineering and computer science, research laboratory of electronics, massachusetts institute of. Zehnder modulators were utilized to produce powerleveled optical frequency combs ofcs from a continuouswave laser. Optical heterodyne detection is a method of extracting information encoded as modulation of. Coherent multi heterodyne spectroscopy using acousto optic. Carlson center for imaging science of the college of science rochester institute of technology july 29, 20. Cavity ringdown spectroscopy crds is a very sensitive technique that has been used with pulsed lasers. Infrared heterodyne spectroscopy is a very attractive method for combining high. The multiheterodyne spectrum exhibits 95 equally spaced frequency comb lines, indicating that the shortwave qcl combs are ideal candidates for highspeed highresolution spectroscopy. This was further extended by the demonstration of its compatibility with modulation techniques, such as wavelength modulation wms12, swept absorption, and swept. Merrimack college, 2011 a thesis submitted in partial ful llment of the requirements for the degree of master of science in the chester f. Lockindetection dualcomb spectroscopy hidenori koresawa et aldualcomb ranging zebin zhu and guanhao wuabsolute distance measurement by multiheterodyne interferometry using an electrooptic triple comb xianyu zhao et althis content was downloaded from ip address 157.
The broadband, coherent nature of narrowlinewidth fiber frequency combs is exploited to measure the full complex spectrum of a molecular gas through multiheterodyne spectroscopy. We measure the absorption and phase shift experienced by each of 155,000. Infrared heterodyne spectroscopy in astronomy albert betz department of physics university of california, berkeley summary a heterodyne spectrometer has been constructed and applied to problems in infrared astronomical spectroscopy. The shs can be made monolithic by fusing all of the main optical elements into a single block with no moving parts. Us8154732b2 multiband spatial heterodyne spectrometer and.
Direct comb multiheterodyne interference spectroscopy. Oct 25, 2017 optical multi dimensional coherent spectroscopy is a powerful technique for studying the structure, properties and ultrafast dynamics of atoms, molecules, semiconductor materials and complex systems. We present a herriotttype multipass laser absorption spectrometer enhanced by optical heterodyne detection. Optical heterodyne detection in cavity ringdown spectroscopy m. Multiheterodyne spectroscopy using fabryperot interband. A heterodyne radiometer system consists of a sensitive, wideband frontend 1 that provides a strong signal at an appropriate frequency for analysis by a low sensitivity single or multichannel detector. Fourier transform spectroscopy fts and cavityring down spectroscopy to enhance sensitivity, but without resolving individual comb lines.
Pdf multiheterodyne spectroscopy with interband cascade. We demonstrate the method using a gaas multiquantum well sample. In a first set of experiments, we demonstrate selfheterodyne interferometry 28, 30 for measuring the transmission peaks of a fabryperot cavity with a submhz resolution. Multiheterodyne spectroscopy using multi frequency combs david f.
The measurement method is based on multi heterodyne downconversion of optical signals. Optical heterodyne detection of laserinduced gratings. Two fabryperot quantum cascade lasers fpqcls are used in a differential dual comb configuration to perform swept multi heterodyne dispersion spectroscopy of low pressure nitrous oxide at khz. Coherent, multiheterodyne spectroscopy using stabilized.