KANA IWAKUNI
| Institute for Laser Science | Associate Professor |
| Department of Engineering Science | Associate Professor |
| Cluster III (Fundamental Science and Engineering) | Associate Professor |
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Paper
- Analysis on high-resolution spectrum of the S1–S0 transition of free-base phthalocyanine
Yuki Miyamoto; Ayami Hiramoto; Kana Iwakuni; Susumu Kuma; Katsunari Enomoto; Naofumi Nakayama; Masaaki Baba
The Journal of Chemical Physics, 14 Apr. 2024, Peer-reviwed
Scientific journal, English - The pressure effect on the line profiles observed in the ν1 + ν3 band of acetylene: Revisited
Sho Okubo; Kana Iwakuni; Hideki Kato; Feng-Lei Hong; Hiroyuki Sasada; Hajime Inaba; Koichi M.T. Yamada
Journal of Molecular Spectroscopy, Elsevier {BV}, 396, 111823-111823, Aug. 2023, Peer-reviwed, In our previous paper [K. Iwakuni et al., Phys. Rev. Lett. 117, 1439026 (2018)] the ortho-para dependence of the pressure effects was reported for the v1 +v3 band of acetylene measured by dual-comb spectroscopy. Sears and coworkers [E.C. Gross et al., J. Chem. Phys. 154, 054305 (2021)] reevaluated the profile parameters for some lines of this band by comb-referenced laser spectroscopy, and pointed out that the ortho-para phenomenon must be a consequence of the use of Voigt function as the profile function, with the Doppler widths fixed at their theoretical values. Thus, we have remeasured this band with two improved spectrometers, the comb-locked laser spectrometer of the National Metrology Institute of Japan and another dual-comb spectrometer of Yokohama National University, and analyzed the lines by using the speed-dependent Voigt function as the profile function with several options. By the present work, we confirm the fact pointed out by Sears and coworkers, and present some remaining problems in the experimental determination of the line profile parameters.
Scientific journal, English - Noise characteristics of a polarization-duplex dual-comb fiber laser based on a single gain fiber
Kana Iwakuni; Aki Takahashi; Sho Okubo
Results in Optics, Elsevier {BV}, 12, 100476-100476, Jul. 2023, Peer-reviwed
Scientific journal, English - Doppler-free Spectroscopy of Buffer-Gas-Cooled Calcium Monohydroxide
Yuki Miyamoto; Reo Tobaru; Yuiki Takahashi; Ayami Hiramoto; Kana Iwakuni; Susumu Kuma; Katsunari Enomoto; Masaaki Baba
JOURNAL OF PHYSICAL CHEMISTRY A, AMER CHEMICAL SOC, 127, 21, 4758-4763, May 2023, In this study, we report the Doppler-free spectra ofbuffer-gas-cooledCaOH. We observed five Doppler-free spectra containing low-J Q(1) and R-12 transitions, which wereonly partially resolved by previous Doppler-limited spectroscopies.The spectra frequencies were corrected using the Doppler-free spectraof iodine molecules; accordingly, the uncertainty was estimated tobe below 10 MHz. We determined the spin-rotation constant inthe ground state, which agrees with the values reported in the literatureobtained based on millimeter-wave data within 1 MHz. This suggeststhat the relative uncertainty is much smaller. The present study demonstratesthe Doppler-free spectroscopy of a polyatomic radical and the broadapplicability of the buffer gas cooling method to molecular spectroscopy.CaOH is the only polyatomic molecule that can be directly laser-cooledand trapped in a magneto-optical trap. High-resolution spectroscopyof such molecules is useful for establishing efficient laser coolingschemes of polyatomic molecules.
Scientific journal, English - Measurement of Doppler effects in a cryogenic buffer-gas cell
Ayami Hiramoto; Masaaki Baba; Katsunari Enomoto; Kana Iwakuni; Susumu Kuma; Yuiki Takahashi; Reo Tobaru; Yuki Miyamoto
PHYSICAL REVIEW A, AMER PHYSICAL SOC, 107, 4, Apr. 2023, Buffer-gas cooling is a universal cooling technique for molecules and used for various purposes. One of its ap- plications is using molecules inside a buffer-gas cell for low-temperature spectroscopy. Although a high-intensity signal is expected in the cell, complex molecular dynamics is a drawback for precise spectroscopy. In this study, we performed high-resolution absorption spectroscopy of low -J transitions in the A similar to 2 pi(0, 0, 0)-X similar to 2E+(0, 0, 0) band of calcium monohydroxide (CaOH). CaOH molecules were produced by laser ablation in a copper cell and cooled to similar to 5 K using helium buffer gas. We probed the Doppler effects in a buffer-gas cell by injecting counterpropagating lasers inside the cell. The time evolutions of the Doppler width and shift were simulated using a dedicated Monte Carlo simulation and compared with data.
Scientific journal, English - High-resolution spectroscopy of buffer-gas-cooled phthalocyanine
Yuki Miyamoto; Reo Tobaru; Yuiki Takahashi; Ayami Hiramoto; Kana Iwakuni; Susumu Kuma; Katsunari Enomoto; Masaaki Baba
COMMUNICATIONS CHEMISTRY, NATURE PORTFOLIO, 5, 1, Nov. 2022, High-resolution molecular spectroscopy provides invaluable insight into the quantum properties of molecules, but high-resolution rovibronic spectroscopy has largely been limited to relatively small systems owing to the difficulty in preparing translationally and rotationally cold samples for large and complex systems. Here, the authors demonstrate that buffer-gas cooling may be an effective strategy to obtain high-resolution rovibronic spectroscopy results for large gas-phase molecules.For over five decades, studies in the field of chemical physics and physical chemistry have primarily aimed to understand the quantum properties of molecules. However, high-resolution rovibronic spectroscopy has been limited to relatively small and simple systems because translationally and rotationally cold samples have not been prepared in sufficiently large quantities for large and complex systems. In this study, we present high-resolution rovibronic spectroscopy results for large gas-phase molecules, namely, free-base phthalocya-nine (FBPc). The findings suggest that buffer-gas cooling may be effective for large molecules introduced via laser ablation. High-resolution electronic spectroscopy, combined with other experimental and theoretical studies, will be useful in understanding the quantum properties of molecules. These findings also serve as a guide for quantum chemical calculations of large molecules.
Scientific journal, English - Low-J Transitions inA2Π (0, 0, 0)- X2Σ+ (0, 0, 0) Band of Buffer-gas-cooled CaOH
Yuiki Takahashi; Masaaki Baba; Katsunari Enomoto; Ayami Hiramoto; Kana Iwakuni; Susumu Kuma; Reo Tobaru; Yuki Miyamoto
The Astrophysical Journal, IOP Publishing Ltd, 936, 2, 1-5, 10 Sep. 2022, Peer-reviwed, Calcium monohydroxide radical (CaOH) is receiving an increasing amount of attention from the astrophysics community as it is expected to be present in the atmospheres of hot rocky super-Earth exoplanets as well as interstellar and circumstellar environments. Here, we report the high-resolution laboratory absorption spectroscopy on low-J transitions in (A) over tilde (2)Pi(0, 0, 0) - (X) over tilde (2)Sigma(+)(0, 0, 0) band of buffer-gas-cooled CaOH. In total, 40 transitions out of the low-J states were assigned, including 27 transitions that have not been reported in previous literature. The determined rotational constants for both ground and excited states are in excellent agreement with previous literature, and the measurement uncertainty for the absolute transition frequencies was improved by more than a factor of 3. This will aid future interstellar, circumstellar, and atmospheric identifications of CaOH. The buffer-gascooling method employed here is a particularly powerful method to probe low-J transitions and is easily applicable to other astrophysical molecules.
Scientific journal, English - Absolute frequency measurement of the 3ν1 band of N2O with comb-locked rapid scan spectroscopy using a multi-pass cell
K. Iwakuni
Journal of Molecular Spectroscopy, ELSEVIER, 384, 1-6, 07 Jan. 2022, Peer-reviwed, The (3)nu(1) vibration band of (N2O)-N-14 at 1.52 mu m is observed with a frequency comb referenced CW laser. Utilizing the high sensitivity and frequency accuracy of a spectrometer, we have determined 47 transition frequencies from P (28) to P(6) and from R(5) to R(28) under a sample pressure of about 40 Pa (300 mTorr) with a measurement uncertainty of 0.55 MHz. We also determined that the self-induced pressure shift coefficient for the P(12) transition is -1.76(7) kHz/Pa (-0.235(9) MHz/Torr). Three molecular constants of the upper state are yielded by fitting the line positions with a standard deviation of 0.71 MHz. The line positions and molecular constants that we determined are consistent with previous work on cavity ring down spectroscopy [G. -L. Liu, et al., J. QUANT. SPECTROSC RADIAT, 229 (2019) 17-22].
Scientific journal, English - Accurate transition frequency list of the nu(3) band of methane from sub-Doppler resolution comb-referenced spectroscopy (vol 30, pg 1027, 2013)
Abe Masashi; Iwakuni Kana; Okubo Sho; Sasada Hiroyuki
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, OPTICAL SOC AMER, 36, 4, 896-896, 01 Apr. 2019, Peer-reviwed
English - Comb-resolved spectroscopy with immersion grating in long-wave infrared
K. Iwakuni; T. Q. Bui; J. F. Niedermeyer; T. Sukegawa; J. Ye
Optics Express, 27, 3, 1911-1921, 04 Feb. 2019, Peer-reviwed
Scientific journal, English - Direct frequency comb spectroscopy with an immersion grating
Kana Iwakuni; Thinh Q. Bui; Justin F. Niedermeyer; Takashi Sukegawa; Jun Ye
2019 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC), IEEE, 2019
International conference proceedings, English - Rotationally-resolved infrared frequency comb spectroscopy of the C60 fullerene
Marissa Weichman; Peter Changala; Thinh Bui; Kana Iwakuni; Justin Niedermeyer; Kevin Lee; Martin Fermann; Jun Ye
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, AMER CHEMICAL SOC, 256, Aug. 2018
English - Phase-stabilized 100 mW frequency comb near 10 mu m
Iwakuni, Kana; Porat; Gil, Bui; Thinh Q; Bjork; Bryce J; Schoun; Stephen B., Heckl; Oliver H; Fermann; Martin E; Ye, Jun
APPLIED PHYSICS B, SPRINGER, 124, 7, 06 Jun. 2018, Peer-reviwed, Long-wavelength mid-infrared (MIR) frequency combs with high power and flexible tunability are highly desired for molecular spectroscopy, including investigation of large molecules such as C-60. We present a high power, phase-stabilized frequency comb near 10 mu m, generated by a synchronously pumped, singly resonant optical parametric oscillator (OPO) based on AgGaSe2. The OPO can be continuously tuned from 8.4 to 9.5 mu m, with a maximum average idler power of 100 mW at the center wavelength of 8.5 mu m. Both the repetition rate (f (rep)) and the carrier-envelope offset frequency (f (ceo)) of the idler wave are phase-locked to microwave signals referenced to a Cs clock. We describe the detailed design and construction of the frequency comb, and discuss potential applications for precise and sensitive direct frequency comb spectroscopy.
Scientific journal, English - Transition dipole-moment of the v(1) + v(3) band of acetylene measured with dual-comb Fourier-transform spectroscopy
Sho Okubo; Kana Iwakuni; Koichi M. T. Yamada; Hajime Inaba; Atsushi Onae; Feng-Lei Hong; Hiroyuki Sasada
JOURNAL OF MOLECULAR SPECTROSCOPY, ACADEMIC PRESS INC ELSEVIER SCIENCE, 341, 10-16, Nov. 2017, Peer-reviwed, The v(1) + v(3) vibration band of acetylene (C2H2) in the near infrared region was recorded with a dual-comb Fourier-transform spectrometer. We observed 56 transitions from P(26) to R(29) at six different column densities. The integral line intensity was determined for each recorded absorption line by fitting the line profile to Lambert-Beer's law with a Voigt function. Thanks to the outstanding capability of dual-comb spectroscopy to cover a broad spectrum in a relatively short time with high resolution and high frequency precision, we determined the reliable line strength for each ro-vibrational transition as well as the transition dipole moment for this band. (C) 2017 The Authors. Published by Elsevier Inc.
Scientific journal, English - Mid-infrared dual-comb spectroscopy with electro-optic modulators
Ming Yan; Pei-Ling Luo; Kana Iwakuni; Guy Millot; Theodor W. Haensch; Nathalie Picque
LIGHT-SCIENCE & APPLICATIONS, CHINESE ACAD SCIENCES, CHANGCHUN INST OPTICS FINE MECHANICS AND PHYSICS, 6, Oct. 2017, Peer-reviwed, Absorption spectroscopy of fundamental ro-vibrational transitions in the mid-infrared region provides a powerful tool for studying the structure and dynamics of molecules in the gas phase and for sensitive and quantitative gas sensing. Laser frequency combs permit novel approaches to perform broadband molecular spectroscopy. Multiplex dual-comb spectroscopy without moving parts can achieve particularly high speed, sensitivity and resolution. However, achieving Doppler-limited resolution in the mid-infrared still requires overcoming instrumental challenges. Here we demonstrate a new approach based on difference-frequency generation of frequency-agile near-infrared frequency combs that are produced using electro-optic modulators. The combs have a remarkably flat intensity distribution, and their positions and line spacings can be freely selected by simply dialing a knob. Using the proposed technique, we record, in the 3-mu m region, Doppler-limited absorption spectra with resolved comb lines within milliseconds, and precise molecular line parameters are retrieved. Our technique holds promise for fast and sensitive time-resolved studies of, for example, trace gases.
Scientific journal, English - Iwakuni et al. reply
KANA IWAKUNI; SHO OKUBO; KOICHI M; T. YAMADA; HAJIME INABA; ATSUSHI ONAE; FENG-LEI HONG; SASADA HIROYUKI
Physical Review Letters, American Physical Society, 119, 069402, 08 Aug. 2017, Peer-reviwed
Scientific journal, English - Generation of a frequency comb spanning more than 3.6 octaves from ultraviolet to mid infrared
Kana Iwakuni; Sho Okubo; Osamu Tadanaga; Hajime Inaba; Atsushi Onae; Feng-Lei Hong; Hiroyuki Sasada
OPTICS LETTERS, OPTICAL SOC AMER, 41, 17, 3980-3983, Sep. 2016, Peer-reviwed, We have observed an ultra-broadband frequency comb with a wavelength range of at least 0.35 to 4.4 mu m in a ridge-waveguide-type periodically poled lithium niobate device. The PPLN waveguide is pumped by a 1.0-2.4 mu m wide frequency comb with an average power of 120 mW generated using an erbium-based mode-locked fiber laser and a following highly nonlinear fiber. The coherence of the extended comb is confirmed in both the visible (around 633 nm) and the mid-infrared regions. (C) 2016 Optical Society of America
Scientific journal, English - Ortho-Para-Dependent Pressure Effects Observed in the Near Infrared Band of Acetylene by Dual-Comb Spectroscopy
Kana Iwakuni; Sho Okubo; Koichi M. T. Yamada; Hajime Inaba; Atsushi Onae; Feng-Lei Hong; Hiroyuki Sasada
PHYSICAL REVIEW LETTERS, AMER PHYSICAL SOC, 117, 14, Sep. 2016, Peer-reviwed, We demonstrate that dual-comb spectroscopy, which allows one to record broadband spectra with high frequency accuracy in a relatively short time, provides a real advantage for the observation of pressurebroadening and pressure-shift effects. We illustrate this with the nu(1) + nu(3) vibration band of (C2H2)-C-12. We observe transitions from P(26) to R(29), which extend over a 3.8 THz frequency range, at six pressures ranging up to 2654 Pa. Each observed absorption line profile is fitted to a Voigt function yielding pressurebroadening and pressure-shift coefficients for each rotation-vibration transition. The effectiveness of this technique is such that we are able to discern a clear dependence of the pressure-broadening coefficients on the nuclear spin state, i.e., on the ortho or para modification. This information, combined with the pressure-shift coefficients, can facilitate a detailed understanding of the mechanism of molecular collisions.
Scientific journal, English - Mid-Infrared Frequency-Agile Dual-Comb Spectroscopy with Doppler-Limited Resolution
Ming Yan; Pei-Ling Luo; Kana Iwakuni; Guy Millot; Theodor W. Haensch; Nathalie Picque
2016 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), IEEE, 2016, Peer-reviwed, Real-time absorption and dispersion dual-comb spectroscopy is achieved in the 3-mu m region without mode-locked lasers or active stabilization. The resolved lines of flat-top frequency combs with adjustable line-spacing and tunable center wavelength enable precise spectroscopy.
International conference proceedings, English - Sub-Doppler resolution mid-infrared spectroscopy using a difference-frequency-generation source spectrally narrowed by laser linewidth transfer
Hideyuki Sera; Masashi Abe; Kana Iwakuni; Sho Okubo; Hajime Inaba; Feng-Lei Hong; Hiroyuki Sasada
OPTICS LETTERS, OPTICAL SOC AMER, 40, 23, 5467-5470, Dec. 2015, Peer-reviwed, The spectral linewidth of a 3.28 mu m difference-frequency-generation source has been reduced to 3.5 kHz using a laser linewidth transfer technique [Opt. Express 21, 7891 (2013)]. We use an optical frequency comb with a broad servo bandwidth to transfer a narrow linewidth of a pump laser, a 1.06 mu m Nd:YAG laser, to a signal laser, a 1.57 mu m external-cavity laser diode. This source enables us to record the Lamb dip of the nu(3) band R(2) E transition of methane with a molecular spectral linewidth of 21 kHz while the frequency axis is absolutely calibrated. (C) 2015 Optical Society of America
Scientific journal, English - Ultra-broadband dual-comb spectroscopy across 1.0-1.9 mu m
Sho Okubo; Kana Iwakuni; Hajime Inaba; Kazumoto Hosaka; Atsushi Onae; Hiroyuki Sasada; Feng-Lei Hong
APPLIED PHYSICS EXPRESS, IOP PUBLISHING LTD, 8, 8, Aug. 2015, Peer-reviwed, We have carried out dual-comb spectroscopy and observed in a simultaneous acquisition a 140-THz-wide spectrum from 1.0 to 1.9 mu m using two fiber-based frequency combs phase-locked to each other. This ultrabroad-wavelength bandwidth is realized by setting the difference between the repetition rates of the two combs to 7.6 Hz using the sub-Hz-linewidth fiber combs. The recorded spectrum contains five vibration-rotation bands of C2H2, CH4, and H2O at different wavelengths across the whole spectrum. The determined transition frequencies of C2H2 agree with those from the previous sub-Doppler resolution measurement of individual lines using CW lasers within 2 MHz. (C) 2015 The Japan Society of Applied Physics
Scientific journal, English - Visible to Mid-Infrared Frequency Comb Generation Using a Waveguide PPLN
Kana Iwakuni; Sho Okubo; Osamu Tadanaga; Hajime Inaba; Atsushi Onae; Feng-Lei Hong; Hiroyuki Sasada
2015 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), IEEE, STh1N, 2015, Peer-reviwed, We succeeded in generating a coherent optical frequency comb covering more than 3 octaves from visible to mid-infrared with a waveguide-type PPLN. The generated comb is demonstrated to be useful for metrology and spectroscopic applications.
International conference proceedings, English - Hyperfine-resolved transition frequency list of fundamental vibration bands of (HCl)-Cl-35 and (HCl)-Cl-37
Kana Iwakuni; Hideyuki Sera; Masashi Abe; Hiroyuki Sasada
JOURNAL OF MOLECULAR SPECTROSCOPY, ACADEMIC PRESS INC ELSEVIER SCIENCE, 306, 19-25, Dec. 2014, Peer-reviwed, Sub-Doppler resolution spectroscopy of the fundamental vibration bands of (HCl)-Cl-35 and (HCl)-Cl-37 has been carried out from 87.1 to 89.9 THz. We have determined the absolute transition frequencies of the hyperfine-resolved R(0) to R(4) transitions with a typical uncertainty of 10 kHz. We have also yielded six molecular constants for each isotopomer in the vibrational excited state, which reproduce the determined frequencies with a standard deviation of about 10 kHz. (C) 2014 Elsevier Inc. All rights reserved.
Scientific journal, English - Design of cavity-enhanced absorption cell for reducing transit-time broadening
Masashi Abe; Kana Iwakuni; Sho Okubo; Hiroyuki Sasada
OPTICS LETTERS, OPTICAL SOC AMER, 39, 18, 5277-5280, Sep. 2014, Peer-reviwed, To reduce the linewidth of Lamb dips, we introduce a cavity-enhanced absorption cell (CEAC) coupled with a Gaussian beam with a 1.9-mm 1/e(2) radius at the beam waist for the reduction of transit-time broadening. We state that transit-time broadening depends only on the beam radius at the beam waist. This fact is useful for the design of the CEAC, and a pair of concave and convex mirrors is thereby employed. We have carried out sub-Doppler resolution spectroscopy of the nu(3) band of CH4 and the nu(1) band of CH3D using a difference-frequency-generation source and the CEAC, and the recorded Lamb dips narrow to 80 kHz (HWHM). (C) 2014 Optical Society of America
Scientific journal, English - Operation of an optically coherent frequency comb outside the metrology lab
L. C. Sinclair; I. Coddington; W. C. Swann; G. B. Rieker; A. Hati; K. Iwakuni; N. R. Newbury
OPTICS EXPRESS, OPTICAL SOC AMER, 22, 6, 6996-7006, Mar. 2014, Peer-reviwed, We demonstrate a self-referenced fiber frequency comb that can operate outside the well-controlled optical laboratory. The frequency comb has residual optical linewidths of < 1 Hz, sub-radian residual optical phase noise, and residual pulse-to-pulse timing jitter of 2.4 - 5 fs, when locked to an optical reference. This fully phase-locked frequency comb has been successfully operated in a moving vehicle with 0.5 g peak accelerations and on a shaker table with a sustained 0.5 g rms integrated acceleration, while retaining its optical coherence and 5-fs-level timing jitter. This frequency comb should enable metrological measurements outside the laboratory with the precision and accuracy that are the hallmarks of comb-based systems. (c) 2014 Optical Society of America
Scientific journal, English - Ultra-Broadband Near-Infrared Dual-Comb Spectroscopy
Okubo S; Iwakuni K; Inaba H; Hosaka K; Onae A; Sasada H; Hong F. L; Ieee
2014 Conference on Lasers and Electro-Optics, IEEE, 2014, Peer-reviwed, We extend the spectral bandwidth of dual-comb spectroscopy over a hundred THz using two optical frequency combs with relative linewidth of sub-Hz level. We record the spectra of the entire vibration band of acetylene.
International conference proceedings, English - Spectroscopy of Yb-171 in an optical lattice based on laser linewidth transfer using a narrow linewidth frequency comb
Hajime Inaba; Kazumoto Hosaka; Masami Yasuda; Yoshiaki Nakajima; Kana Iwakuni; Daisuke Akamatsu; Sho Okubo; Takuya Kohno; Atsushi Onae; Feng-Lei Hong
OPTICS EXPRESS, OPTICAL SOC AMER, 21, 7, 7891-7896, Apr. 2013, Peer-reviwed, We propose a novel, high-performance, and practical laser source system for optical clocks. The laser linewidth of a fiber-based frequency comb is reduced by phase locking a comb mode to an ultrastable master laser at 1064 nm with a broad servo bandwidth. A slave laser at 578 nm is successively phase locked to a comb mode at 578 nm with a broad servo bandwidth without any pre-stabilization. Laser frequency characteristics such as spectral linewidth and frequency stability are transferred to the 578-nm slave laser from the 1064-nm master laser. Using the slave laser, we have succeeded in observing the clock transition of Yb-171 atoms confined in an optical lattice with a 20-Hz spectral linewidth. (c) 2013 Optical Society of America
Scientific journal, English - Accurate transition frequency list of the nu(3) band of methane from sub-Doppler resolution comb-referenced spectroscopy
Masashi Abe; Kana Iwakuni; Sho Okubo; Hiroyuki Sasada
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, OPTICAL SOC AMER, 30, 4, 1027-1035, Apr. 2013, Peer-reviwed, We have carried out sub-Doppler resolution spectroscopy of the nu(3) band of (CH4)-C-12 using a difference-frequency-generation source, an enhanced cavity absorption cell, and an optical frequency comb, and we have added 150 lines to the transition frequency list published earlier [Opt. Express 19, 23878 (2011)]. It now covers 204 lines from the P(12) to R(8) transitions, involving 21 weak forbidden transitions, with a typical uncertainty of 3 kHz for allowed transitions and 12 kHz for forbidden transitions. The combination differences between the allowed and forbidden transitions enable us to determine a scalar rotational constant and three scalar distortion constants of the ground vibrational state with greatly reduced uncertainties. (C) 2013 Optical Society of America
Scientific journal, English - Precision Measurement with Optical Frequency Combs and Clocks
Hong F. L; Inaba H; Iwakuni K; Nakajima Y; Hosaka K; Yasuda M; Kohno T; Akamatsu D; Tanabe T; Okubo S; Suzuyama T; Amemiya M; Onae A; Ieee
2013 Conference on Lasers and Electro-Optics Pacific Rim, IEEE, 2013, Peer-reviwed, We have being developing optical frequency combs, especially fiber-based frequency combs with narrow linewidth, for laser frequency measurement and control. We are also working on Yb and Sr optical lattice clocks for precision frequency metrology.
International conference proceedings, English - Accurate Frequency Measurement of the v(3) Band of Methane from Sub-Doppler Resolution Comb-Referenced Spectroscopy
Abe M; Okubo S; Iwakuni K; Nakayama H; Inaba H; Sasada H; Iee
2013 Conference on Lasers and Electro-Optics Pacific Rim, 2013, Peer-reviwed - A novel frequency control scheme for combreferenced sensitive difference-frequencygeneration spectroscopy
Kana Iwakuni; Sho Okubo; Hiroyuki Sasada
Optics Express, Optical Society of American (OSA), 21, 12, 14832-14840, 2013, Peer-reviwed, We present a novel scheme of frequency scan and wavelength modulation of a difference-frequency-generation source for comb-referenced sensitive spectroscopy. While the pump and signal frequencies are phase-locked to an optical frequency comb (OFC), the offset frequency between the signal wave and the nearest comb tooth is modulated to apply a wavelength-modulation technique, and the idler wave frequency is repeatedly swept for signal accumulation by changing the repetition frequency of the OFC. The spectrometer is applied to absolute frequency measurement of weak hyperfine-resolved rovibration transitions of the ν1 band of CH3I, and the uncertainty in frequency determination is reduced by one order of magnitude in compared with that of the previous work published in Optics Express 20, 9178-9186 (2012). © 2013 Optical Society of America.
Scientific journal, English - Modulation-free laser frequency stabilization to a saturated sub-Doppler spectral line in a transversal magnetic field
Sho Okubo; Kana Iwakuni; Taro Hasegawa
OPTICS COMMUNICATIONS, ELSEVIER SCIENCE BV, 285, 20, 4107-4111, Sep. 2012, Peer-reviwed, We demonstrate frequency stabilization of a modulation-free laser to a saturated absorption spectral line of atoms in a transversal magnetic field. This stabilization scheme has been proposed for wide capture range in comparison with the dichroic atomic vapor laser lock (DAVLL) scheme and demonstrated for a Doppler-broadened spectral line in J. Opt. Soc. Am. B, 26, 1216 (2009). In this paper, a 1083-nm external-cavity laser diode is frequency-stabilized to the sub-Doppler spectral line of helium transition (2(3)S(1),m(J) = 0 <-> 2(3)P(0)). Even though the error signal shape strongly depends on the pump beam polarization, the stabilized frequency is expected to be insensitive to the pump beam polarization. (C) 2012 Elsevier B.V. All rights reserved.
Scientific journal, English - Narrow linewidth comb realized with a mode-locked fiber laser using an intra-cavity waveguide electro-optic modulator for highspeed control
Kana Iwakuni; Hajime Inaba; Yoshiaki Nakajima; Takumi Kobayashi; Kazumoto Hosaka; Atsushi Onae; Feng-Lei Hong
OPTICS EXPRESS, OPTICAL SOC AMER, 20, 13, 13769-13776, Jun. 2012, Peer-reviwed, We have developed an optical frequency comb using a mode-locked fiber ring laser with an intra-cavity waveguide electro-optic modulator controlling the optical length in the laser cavity. The mode-locking is achieved with a simple ring configuration and a nonlinear polarization rotation mechanism. The beat note between the laser and a reference laser and the carrier envelope offset frequency of the comb were simultaneously phase locked with servo bandwidths of 1.3 MHz and 900 kHz, respectively. We observed an out-of-loop beat between two identical combs, and obtained a coherent delta-function peak with a signal to noise ratio of 70 dB/Hz. (C) 2012 Optical Society of America
Scientific journal, English - Toward an optical frequency comb with relative frequency uncertainty at 10(-21)-level
Inaba H; Nakajima Y; Iwakuni K; Hosaka K; Onae A; Yasuda M; Akamatsu D; Hong F. L; Ieee
2012 Conference on Lasers and Electro-Optics, IEEE, 2012, Peer-reviwed, We report as regards an optical-optical frequency transfer with relative frequency stability at 10(-21)-level by canceling fiber noise between plural optical amplifier branches.
International conference proceedings, English - Absolute frequency list of the v(3)-band transitions of methane at a relative uncertainty level of 10(-11)
Sho Okubo; Hirotaka Nakayama; Kana Iwakuni; Hajime Inaba; Hiroyuki Sasada
OPTICS EXPRESS, OPTICAL SOC AMER, 19, 24, 23878-23888, Nov. 2011, Peer-reviwed, We determine the absolute frequencies of 56 rotation-vibration transitions of the v(3) band of CH4 from 88.2 to 90.5 THz with a typical uncertainty of 2 kHz corresponding to a relative uncertainty of 2.2 x 10(-11) over an average time of a few hundred seconds. Saturated absorption lines are observed using a difference-frequency-generation source and a cavity-enhanced absorption cell, and the transition frequencies are measured with a fiber-laser-based optical frequency comb referenced to a rubidium atomic clock linked to the international atomic time. The determined value of the P(7) F-2((2)) line is consistent with the International Committee for Weights and Measures recommendation within the uncertainty. (C) 2011 Optical Society of America
Scientific journal, English - Low noise optical frequency synthesizer for optical lattice clocks
Inaba H; Nakajima Y; Hosaka K; Iwakuni K; Yasuda M; Akamatsu D; Kohno T; Onae A; Hong F.-L
Proceedings - 2010 12th International Conference on Electromagnetics in Advanced Applications, ICEAA'10, 813-816, 2010, Peer-reviwed - Fiber-based frequency combs with millihertz-level relative linewidths for optical lattice clocks
Inaba H; Nakajima Y; Hosaka K; Iwakuni K; Yasuda M; Kohno T; Akamatsu D; Minoshima K; Onae A; Hong F. L; Ieee
2010 Conference on Precision Electromagnetic Measurements Cpem, IEEE, 442-443, 2010, Peer-reviwed, Monday Tuesday Wednesday Thursday Friday We have been developing a new clock laser system for Yb and Sr optical lattice clocks. The system is based on an infrared laser with a narrow linewidth, and a fiber-based frequency comb transferring the linewidth to required plural wavelengths. We demonstrate that fiber-based frequency combs with a multi-branch configuration can transfer laser linewidth to another wavelength at the millihertz level. An intra-cavity electro-optic modulator is employed to obtain a broad servo bandwidth for repetition rate control.
International conference proceedings, English - All-fiber-based frequency comb with an intra-cavity waveguide electro-optic modulator
Nakajima Y; Inaba H; Iwakuni K; Hosaka K; Onae A; Minoshima K; Hong F. L; Ieee
2010 Conference on Lasers and Electro-Optics, IEEE, 2010, Peer-reviwed, We develop an all-fiber-based frequency comb with an intra-cavity waveguide electro-optic modulator. A comb mode is successfully phase-locked to an optical reference. The servo bandwidth of repetition rate is approximately 400 kHz. (C)2010 Optical Society of America
International conference proceedings, English - A new clock laser system for an Yb optical lattice clock using a fibre-based frequency comb stabilized to a narrow linewidth laser at 1064 nm
Hosaka K; Inaba H; Nakajima Y; Iwakuni K; Yasuda M; Kohno T; Akamatsu D; Onae A; Hong F. L; Ieee
2010 Conference on Precision Electromagnetic Measurements Cpem, 18-19, 2010, Peer-reviwed
MISC
- 光コムを用いた高性能分光計測法─デュアルコム分光計はFTIR を駆逐するか─
佐々田博之; 岩國加奈
日本光学会, Nov. 2019, 光学, 48, 11, 457-461, Japanese, Peer-reviwed, Introduction scientific journal - 分光応用のための3.6オクターブ超広帯域光コム
OKUBO SHO; IWAKUNI KANA; TADANAGA OSAMU; INABA HAJIME; HONG FENG-LEI; SASADA HIROYUKI
応用物理学会フォトニクス分科会, Jul. 2018, フォトニクスニュース, 4, 2, 69-73, Japanese, Peer-reviwed, Invited, Introduction commerce magazine - Development of Fiber-Laser-Based Broadband Dual-comb System and Its Spectroscopic Applications
大久保 章; 岩國 加奈; 山田 耕一; 洪 鋒雷; 佐々田 博之; 稲場 肇
レーザー学会研究委員会, 10 Nov. 2017, レーザー学会研究会報告 = Reports the on topical meeting of the Laser Society of Japan, 17, 34, 29-34, Japanese, 40021405143 - 光コムが可能にする高分解能分光と基礎科学への応用
SASADA HIROYUKI; OKUBO SHO; IWAKUNI KANA
オプトロニクス社, 10 Oct. 2017, オプトロニクス, 36, 10, 99-105, Japanese, Invited, Introduction commerce magazine - 光コムによる知的光シンセサイザと応用展開 光コムが可能にする高分解能分光と基礎科学への応用
佐々田博之; 大久保章; 岩國加奈
10 Oct. 2017, Optronics, 430, 99‐105, Japanese, 0286-9659, 201702264285631480 - 光コムを用いた精密分光による分子衝突過程の核スピン依存性の発見
岩國加奈
丸善, Jan. 2017, パリティ, 32, 1, Japanese, Introduction commerce magazine - 24aAG-2 Linewidth Reduction of Mid-infrared Light Source using Frequency Comb with fast frequency control
Sera H; Abe M; Iwakuni K; Okubo S; Inaba H; Hong F. -L; Sasada H
The Physical Society of Japan, 2015, Meeting Abstracts of the Physical Society of Japan, 70, 0, Japanese, 110009989656 - 30pCF-4 Ultra-Broadband Spectroscopy with a Dual-Comb Spectrometer
Iwakuni Kana; Okubo Sho; Inaba Hajime; Hosaka Kazumoto; Onae Astushi; Sasada Hiroyuki; Hong Feng-Lei
The Physical Society of Japan (JPS), 2014, Meeting Abstracts of the Physical Society of Japan, 69, 0, Japanese, 1342-8349, 110009834357 - 10aAW-4 Observation of Ultra-Broadband Absorption Spectrum using a Dual-Comb Spectrometer
Iwakuni K; Okubo S; Inaba H; Hosaka K; Onae A; Sasada H; Hong F. -L
The Physical Society of Japan (JPS), 2014, Meeting Abstracts of the Physical Society of Japan, 69, 0, Japanese, 1342-8349, 110009875537 - 高速制御型光周波数コムの高繰り返し周波数化および高出力化
鈴木淳太; 鈴木淳太; 稲場肇; 稲場肇; 保坂一元; 小口研一; 小口研一; 大久保章; 岩國加奈; 岩國加奈; 大苗敦; 赤松大輔; HONG Feng-Lei
2013, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 74th, 201302261309016494 - Development of the dual-comb system using narrow linewidth optical frequency combs
Iwakuni K; Okubo S; Inaba H; Hasegawa T; Hosaka K; Onae A; Sasada H; Hong F.-L
The Physical Society of Japan (JPS), 2013, Meeting Abstracts of the Physical Society of Japan, 68, 0, Japanese, 1342-8349, 110009754742 - Broadband C2H2 spectroscopy with a dual-comb system
Okubo S; Iwakuni K; Inaba H; Hasegawa T; Hosaka K; Onae A; Sasada H; Hong F.-L
The Physical Society of Japan (JPS), 2013, Meeting Abstracts of the Physical Society of Japan, 68, 0, Japanese, 1342-8349, 110009754743 - 20aAJ-10 Modulation-free laser frequency stabilization to a saturated sub-Doppler spectral line in a transversal magnetic field
Okubo Sho; Iwakuni Kana; Hasegawa Taro
The Physical Society of Japan (JPS), 24 Aug. 2012, Meeting abstracts of the Physical Society of Japan, 67, 2, 164-164, Japanese, 1342-8349, 110009601885, AA11439205 - 27pSA-7 Spectral narrowing of a mid-infrared differential frequency generation source stabilized to an optical frequency comb
Iwakuni Kana; Okubo Sho; Nakayama Hirotaka; Sasasda Hiroyuki
The Physical Society of Japan (JPS), 05 Mar. 2012, Meeting abstracts of the Physical Society of Japan, 67, 1, 245-245, Japanese, 1342-8349, 110009565701, AA11439205 - 28aRD-4 Development of narrow linewidth clock lasers for optical lattice clocks using a high-speed controllable fibre comb
Hosaka K; Inaba H; Nakajima Y; Iwakuni K; Yasuda M; Kohno T; Onae A; Hong F.-L
The Physical Society of Japan (JPS), 2011, Meeting Abstracts of the Physical Society of Japan, 66, 0, Japanese, 1342-8349, 110008610515 - 狭線幅ファイバコムの開発と応用
中嶋善晶; 中嶋善晶; 稲場肇; 稲場肇; 岩國加奈; 岩國加奈; 保坂一元; 保坂一元; 大苗敦; 安田正美; 安田正美; 赤松大輔; 赤松大輔; HONG Feng-Lei; HONG Feng-Lei
2010, 応用物理学会学術講演会講演予稿集(CD-ROM), 71st, 201002267454754980 - 光格子時計のための新しい狭線幅レーザー光源
保坂一元; 稲場肇; 中嶋善晶; 岩國加奈; 岩國加奈; 安田正美; 河野託也; 赤松大輔; 大苗敦; HONG Feng-Lei
2010, 応用物理学会学術講演会講演予稿集(CD-ROM), 71st, 201002277723282807
Lectures, oral presentations, etc.
- バッファガスセル内におけるCaOHのドップラー効果の研究
桃原怜央; 平本綾美; 高橋唯基; 岩國加奈; 久間晋; 榎本勝成; 馬場正昭; 宮本祐樹
Oral presentation, Japanese, 日本物理学会秋季大会, Domestic conference
14 Sep. 2022 - バッファガス冷却分光法による大型分子の回転構造の観測
宮本祐樹; 桃原怜央; 高橋唯基; 平本綾美; 岩國加奈; 久間晋; 榎本勝成; 馬場正昭
Oral presentation, Japanese, 日本物理学会秋季大会, Domestic conference
14 Sep. 2022 - 光コムを用いた精密分子分光
岩國加奈
Oral presentation, Japanese, 冷却分子・精密分光シンポジウム, Domestic conference
26 Aug. 2022 - Polarization multiplex dual-comb fiber laser for precise spectroscopy
A. Takahashi; S. Okubo; K. Iwakuni
Oral presentation, English, CLEO-Pacific Rim 2022, International conference
04 Aug. 2022 - バッファガス冷却されたCaOH分子のAX遷移高分解能分光
宮本祐樹; 高橋唯基; 平本綾美; 岩國加奈; 久間晋; 榎本勝成; 馬場正昭
Oral presentation, Japanese, 日本物理学会 第77回年次大会, Domestic conference
16 Mar. 2022 - バッファガス冷却されたCaOH分子の分光
高橋唯基; 桃原怜央; 岩國加奈; 久間晋; 榎本勝成; 馬場正昭; 宮本祐
Oral presentation, Japanese, 日本物理学会秋季大会, Domestic conference
03 Sep. 2021 - バッファガス冷却された多原子分子源の研究開発
高橋唯基; 桃原怜央; 岩國加奈; 久間晋; 宮本祐樹
Oral presentation, Japanese, 日本物理学会, Domestic conference
12 Mar. 2021 - Absolute frequency measurement of N2O at 1.52um
K.Iwakuni
Oral presentation, English, The 4th Asian Workshop on Molecular Spectroscopy, International conference
10 Mar. 2021 - 新奇デュアルコム分光計の開発に向けたモード同期ファイバーコムの開発
髙橋亜稀; 岩國加奈
Oral presentation, Japanese, 第21回分子分光研究会, Domestic conference
08 Mar. 2021 - 気相分子冷却に向けたアブレーション生成物のバッファーガス冷却とその分光
宮本祐樹; 久間晋; 岩國加奈
Oral presentation, Japanese, 日本物理学会, Domestic conference
10 Sep. 2020 - 中赤外光コムを用いた分子分光
岩國加奈
Oral presentation, Japanese, 日本光学会年次学術講演会（OPJ）, Domestic conference
14 Dec. 2019 - 高速広帯域分光に向けた分散素子を用いた光コム分光計
岩國加奈
Oral presentation, Japanese, 第19回分子分光研究会, Domestic conference
26 Mar. 2019