A 180 GHZ PULSED TRANSMITTER AND HETERODYNE RECEIVER 28 NM CMOS CHIPSET FOR MOLECULAR SENSING

The size, weight, and power requirements of emerging millimeter-wave transmitter and receiver integrated circuit elements make them ideally suited for use in high-resolution \textit{in situ} gas sensors. Previous work at the Jet Propulsion Laboratory has demonstrated a tunable 90-105 GHz transmitter fabricated in 65 nm complementary metal-oxide semiconductor (CMOS) process having phase noise and output power characteristics suitable for making sub-doppler measurements when deployed as the source in a traditional frequency modulated absorption spectrometer.\footnote{D. J. Nemchick \textit{et al.}, ``Sub-Doppler spectroscopy with a CMOS transmitter," \textit{IEEE Trans. THz Sci. Technol.}, vol. 8, no. 1, pp. 121-126, 2018.} When paired with a heterodyne receiver of complementary bandwidth and cavity end mirror outfitted with embedded coplanar waveguides a miniaturized cavity enhanced pulsed Fourier transform spectrometer can be realized where all source and detection electronics are housed on a single 100 cm$^{2}$ printed circuit board. \footnote{D. J. Nemchick \textit{et al.}, A 90-102 GHz CMOS based pulsed Fourier transform spectrometer: New approaches for \textit{in situ} chemical detection and millimeter-wave cavity-based molecular spectroscopy \textit{Rev. Sci. Inst.}, vol. 89, pp. 073109:1-12, 2018} This talk will highlight ongoing work to expand our current capabilities in order to target more strategic molecular transitions, such as the $3_{1,3} \leftarrow 2_{2,0}$ ($J^{\prime\prime}_{K^{\prime\prime}_{a},K^{\prime\prime}_{c}} \leftarrow J^{\prime}_{K^{\prime}_{a},K^{\prime}_{c}}$) H$_{2}$O line at 183.310 GHz, with a new Tx/Rx chipset. Unlike the previous generation these integrated circuit elements, now fabricated with 28 nm CMOS techniques, deploy a 90 GHz phase-lock loop the output of which is either frequency doubled, pulse modulated, then amplified (as in Tx) or frequency doubled for use in pumping a down-conversion mixer (as in Rx). Preliminary results will be presented along with a discussion on how the higher frequency radiation generated from these devices can be coupled into (and out of) an optical cavity to allow for exploitation of sensitive pulsed emission schemes

DEMONSTRATION OF A 180 GHZ FULL CMOS SPECTRALLY DISPERSED HETERODYNE RADIOMETER WITH InP LNA FOR REMOTE SENSING

Widespread deployment (both ground-based and spaceborne) of millimeter/submillimeter radiometers for composition specific atmospheric retrievals has been hindered by the cost, complexity, and power requirements traditionally associated with this hardware. One possible avenue to make such measurements more routine are millimeter-wave (180-200 GHz) heterodyne-detection electronics fabricated with complementary metal-oxide semiconductor (CMOS) process techniques. When outfitted with indium phosphide (InP) low-noise amplifier (LNA) stages, cryogen free system temperatures (T$_{sys}$) of 800 - 1000 K can be achieved. This receiver system has been equipped with with a custom 6GS/s ADC / FFT (3GHz bandwidth) system-on-chip to spectrally disperse the generated intermediate frequency signal to allow for composition specific measurements of gas-phase samples.\footnote{Y. Kim \textit{et al.}, ``A 183-GHz InP/CMOS-Hybrid Heterodyne-Spectrometer for Spaceborne Remote Sensing," \textit{IEEE Trans. THz Sci. Technol.}, In Review.} The resulting system can be configured to meet the stringent size and power requirements needed for CubeSat/SmallSat integration thus making for a potentially useful planetary science instrument (i.e., limb sounder). This talk will discuss the performance properties of all components, laboratory trails demonstrating sensitivity to rarefied samples of CH$_{3}$CN and H$_{2}$O, and future plans for field deployment on ground-based and stratospheric balloon platforms

180 GHZ RESONANT CAVITY FOR FOURIER TRANSFORM MILLIMETER-WAVE IN-SITU SENSING

The development of portable millimeter-wave gas sensors that operate using pulsed Fourier transform detection schemes and meet the stringent demands for space deployment depend on the advancement of several key technologies. A prototype system\footnote{Nemchick, \textit{et al.}, A 90-102 GHz CMOS based pulsed Fourier transform spectrometer: New approaches for \textit{in situ} chemical detection and millimeter-wave cavity-based molecular spectroscopy \textit{Rev. Sci. Inst.}, vol. 89, pp. 073109:1-12, 2018} that operates at 90-100 GHz has already been demonstrated with efforts now focusing on a system to target the $3_{1,3} \leftarrow 2_{2,0}$ ($J^{\prime\prime}_{K^{\prime\prime}_{a},K^{\prime\prime}_{c}} \leftarrow J^{\prime}_{K^{\prime}_{a},K^{\prime}_{c}}$) H$_{2}$O transition at 183.310 GHz. The performance properties of a 180-190 GHz CMOS-based pulsed transmitter and heterodyne receiver set has already proven viable for system incorporation.\footnote{Nemchick, \textit{et al.}, "A 180 GHz Pulsed Transmitter and Heterodyne Receiver 28 NM CMOS Chipset for Molecular Sensing", International Symposium on Molecular Spectroscopy, Urbana-Champaign, IL, 2019} Another key component is the hybrid coupling plate that interfaces with the integrated circuit transmitter and receiver chips and serves as the cavity end mirror of the resonant sample cell. The performance of the waveguide fed version of this cavity system will be discussed including demonstrative examples of cavity quality factor measurements (Q$>$10000) and molecular detections deploying both CMOS and traditional mm-wave sources/detectors. System performance will be discussed in the context of realizing a dual band system capable of near simultaneous detection of both H$_{2}$O (at 183.310 GHz) and D$_{2}$O (at 80.359 GHz)

HIGH-RESOLUTION THz MEASUREMENTS OF BrO GENERATED IN AN INDUCTIVELY COUPLED PLASMA

Building upon the foundation provided by previous work, the textit{X}$_{1}$$^{2}$$Pi$$_{3/2}$ and textit{X}$_{2}$$^{2}$$Pi$$_{1/2}$ states of the transient radical, BrO, were interrogated in previously unprobed spectral regions (0.5 to 1.7 THz) by employing JPL developed high-resolution cascaded frequency multiplier sources. Like other members of the halogen monoxides (XO), this species has been the target of several recent atmospheric remote sensing studies and is a known participant in a catalytic ozone degradation cycle. For the current work, BrO is generated in an inductively coupled plasma under dynamic flow conditions and rotational lines are observed directly at their Doppler-limited resolution. New spectral transitions including those owing to both the ground ($nu$=0) and excited ($nu$=1 and 2) vibrational states of isotopologues composed of permutations of natural abundance $^{16}$O, $^{18}$O, $^{79}$Br, and $^{81}$Br are fit to a global Hamiltonian containing both fine and hyperfine terms. In addition to further refining existing spectroscopic parameters, new observations will be made available to remote detection communities through addition to the JPL catalog. New findings will be discussed along with future plans to extend these studies to other halogen monoxides (X=Cl and I) and the more massive halogen dioxides (OXO & XOO)

STRATOSPHERIC WATER OBSERVATION WITH A BALLOON BORNE SPECTRALLY DISPERSED CMOS BASED HETERODYNE RADIOMETER

The deployment of millimeter wave and terahertz heterodyne radiometers has traditionally been reserved for large flagship space missions (e.g., Hershel HIFI, UARS MLS) owing to the size, weight, and power requirements associated with this class of remote sensing instrumentation. Ongoing efforts at the Jet Propulsion Laboratory aims to reduce system complexity by utilizing high speed phase-lock loops embedded in CMOS process integrated circuitry for use as a local oscillator to pump an on chip downconversion mixer. The noise temperature of the resulting CMOS-based mm-wave heterodyne receiver system (180-190 GHz) can be reduced with custom designed InP low-noise amplifier stages to values sufficiently low (T$_{sys}$=800 - 1000 K) to allow for remote molecular detections with sub-second integration times. A deployable system, having a form factor commensurate with a 6U cubesat, can be realized by pairing this receiver with a purpose design and built 6 GS/s real-time ADC/FFT integrated circuit chip to process the intermediate frequency signal generated by the frontend receiver.\footnote{Y. Kim \textit{et al.}, ``A 183-GHz InP/CMOS-Hybrid Heterodyne-Spectrometer for Spaceborne Remote Sensing," \textit{IEEE Trans. THz Sci. Technol.}, vol. 9(3). pp. 313-334, 2019} An engineering test flight of this system was completed as part of the Fort Sumner, NM Fall 2019 stratospheric ballooning campaign. This talk will discuss instrument performance including pre-flight laboratory testing and molecular detections observed in the radiometrically calibrated data recorded at an altitude of 38 km (125000 ft)

PULSE-ECHO MILLIMETER WAVE IN SITU SENSOR WITH 65 nm CMOS TRANSMITTER AND HETERODYNE RECEIVER ELECTRONICS

\begin{wrapfigure}{l}{0pt} \includegraphics[scale=0.2]{Specchip_ISMS2018_DJN.eps} \end{wrapfigure} Cavity enhanced pure rotational spectroscopy has long been a potent laboratory tool for the elucidation of structure and dynamics in isolated molecular systems where sensitive pulsed-echo techniques are routinely performed up to frequencies as high $\sim$50 GHz. Although the associated narrow linewidths ($\sim$800kHz), wide-bandwidth (often $>$10 GHz), and long optical path lengths have long been identified as a desirable combination for sensitive and specific gas sensing, the unaccommodating size and power requirements of traditional microwave optics/electronics are unsuitable for the stringent demands required for \textit{in situ} deployment. Additionally, efforts to drive pulsed-echo techniques into millimeter and submillimeter wavelength regimes, where the size of optics can be reduced without suffering large diffraction losses, have failed largely due to inefficiencies of injecting radiation into the resonant optical cavity. Recent pursuits at the Jet Propulsion Laboratory to realize compact, low-power devices capable of \textit{in situ} chemical detections on extra-terrestrial objects have found success in calling upon novel transmitter and receiver elements built from CMOS architectures commonly employed in the high-speed communications industry. These low-power integrated circuit chipsets can be embedded directly into quasi-optical devices allowing for the realization of cavity based instruments where all source and detection electronics are hosted by a single 16 in$^2$ printed circuit board. The current talk will present a full system description of this miniaturized CMOS-based pulse-echo rotational spectrometer,\footnote{D. J. Nemchick \textit{et al.}, ``A 90-102\thinspace GHz CMOS Based Pulsed-Echo Fourier Transform Spectrometer: New Approaches for \textit{In Situ} Chemical Detection and Millimeter-Wave Cavity-Based Molecular Spectroscopy," \textit{Rev. Sci. Inst.}, In Submission.} which has an operational bandwidth of 90-105 GHz, along with experimental trials taken in bulk gas flows and seeded molecular beam environments

A USB - TO - W-BAND TRANSMITTER: MILLIMETER-WAVE MOLECULAR SPECTROSCOPY WITH CMOS TECHNOLOGY

\begin{wrapfigure}{l}{0pt} \includegraphics[scale=0.5]{Tx_ISMS2018_DJN.eps} \end{wrapfigure}The distinct rotational signatures of gas-phase molecular species in the millimeter (mm) and sub- millimeter (sub-mm) spectral regions have long assisted remote sensing communities in the interrogation of atmospheric and astrophysical media. \textit{In situ} studies employing highly-mobile instrumentation have not been able to reproduce the success of their remote-based counterparts largely due to the unaccommodating size and power requirements of traditional mm and sub-mm wave hardware. The Laboratory Studies and Atmospheric Observations group at JPL has embraced the marriage of novel custom-designed CMOS source and heterodyne detection electronics, which often leverage advances in the mobile phone industry, and traditional cavity enhanced laboratory techniques to combat the issues that have plagued the deployment of in situ mm wave sensors. One device emerging from these efforts is a freestanding CMOS-based transmitter tunable to sub-500 Hz resolution over the operational bandwidth of 90 – 105 GHz. For prototyping purposes this transmitter, the output of which can be both frequency and amplitude modulated, has been deployed as the radiation source in a high- resolution sub-Doppler (Lamb-dip) absorption spectrometer. The presented experimental findings have shown that this device, which effectively functions as a USB powered/controlled W-band source, has sufficient output power ($\sim$2 mW peak) to perform spectral-hole burning saturation experiments and a phase-noise floor low enough to determine spectral line positions with a precision of 1 part in 10$^9$ and accuracy within the error of measurements made with traditional millimeter-wave sources.\footnote{D. J. Nemchick \textit{et al.}, ``Sub-Doppler Spectroscopy With a CMOS Transmitter," \textit{IEEE Trans. THz Sci. Technol.}, vol. 8, no. 1, pp. 121-126, 2018.} These findings highlight the promise of exploiting CMOS architectures for use in gas specific, low-power, and potentially low-cost \textit{in situ} sensors

Decisive test of color transparency in exclusive electroproduction of vector mesons

The exclusive production of vector mesons in deep inelastic scattering is a hard scattering process with the well controlled size of quark configurations which dominate the production amplitude. This allows an unambiguous prediction of color transparency effects in the coherent and incoherent production of vector mesons on nuclei. We demonstrate how the very mechanism of color transparency leads to a belated onset of color transparency effects as a function of $Q^{2}$. We conclude that the $Q^{2}$ dependence of the exclusive $\rho^{0}$-meson production on nuclei and nucleons observed in the Fermilab E665 experiment gives a solid evidence for the onset of color transparency. We propose the scaling relation between the $\rho^{0}$ and the $J/\Psi$ production, which further tests the mechanism of color transparency in exclusive (virtual) photoproduction.Comment: 11 pages, 4 figures on the request from [email protected], Juelich preprint KFA-IKP(Th)-1993-27. \phantom{.}\hspace{9cm}{\sl 8 November 1993

Novel Color Transparency Effect: Scanning the Wave Function of Vector Mesons

We demonstrate how the virtual photoproduction of vector mesons on nuclei scans the wave function of vector mesons from the large non-perturbative transverse size $\rho \sim R_{V}$ down to the small perturbative size $\rho \sim 1/\sqrt{Q^{2}}$. Thee mechanism of scanning is based on color transparency and QCD predicted spatial wave function of quark-antiquark fluctuations of virtual photons. A rich, energy- and $Q^{2}$-dependent, pattern of the nuclear shadowing and antishadowing is predicted, which can be tested at the European Electron Facility and SLAC.Comment: TRI-PP-93-5, LaTeX file, 11 pages + 3 figures (not included, available by fax

Nuclear-Medium Modification of the Rho(1S)- and Rhoprim(2S)-Mesons in Coherent Photo- and Electroproduction: Coupled Channel Analysis

We study medium modifications of the dilepton mass spectrum in coherent photo- and electroproduction of the Rho(1S)- and Rhoprim(2S)-meson resonances on nuclear targets. The analysis is performed within the coupled Rho, Rhoprim... channel formalism in which nuclear modifications derive from the off-diagonal rescatterings. We find that the effect of off-diagonal rescatterings on the shape of the dilepton mass spectrum in the Rho(1S)-meson mass region is only marginal but is very important in the Rhoprim mass region. The main off-diagonal contribution in the Rhoprim mass region comes from the sequential mechanism gamma* -> Rho -> Rhoprim(2S), which dominates the Rhoprim(2S) production for heavy nuclei. Our results show also that in the Rhoprim(2S) mass region there is a considerable effect of the interference of the Breit-Wigner tail of Rho(1S)-meson with the Rhoprim-meson.Comment: 18 pages, 9 figure