Browsing by Author "Kung, A. H."

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Arbitrary waveform synthesis by multiple harmonics generation and phasing in aperiodic optical superlattices
(2009-08-31)
Lin, Wei-Hsun
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Kung, A. H.
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光電工程學系
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Department of Photonics
The process of generating periodic optical waveforms includes the generation and phasing of several harmonics of a fundamental frequency. In this work, we show that simultaneous generation and phasing of the harmonics can be performed in a monolithic aperiodic optical superlattice (AOS). Stable periodic waveforms can thus be delivered to a predetermined location by simply sending a laser beam through a properly designed and fabricated AOS crystal. A detailed mathematical description for generating the domain pattern in such an AOS crystal is given and the process is numerically demonstrated. The waveform that is generated from a monolithic AOS is highly reproducible and phase stable. We also use propagation in air as an example to show how any predictable phase and amplitude modifications such as air dispersion that will alter the desired waveform can be pre-compensated in the design phase of the AOS crystal. (C) 2009 Optical Society of America
Autoionizing Rydberg series (np ', nf ') of Ar investigated by stepwise excitations with lasers and synchrotron radiation
(2008-08-01)
Lee, Yin-Yu
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Dung, Tzan-Yi
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Hsieh, Re-Ming
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Yuh, Jih-Young
;
Song, Yen-Fang
Synchrotron radiation is used to excite Ar to the intermediate states 3p(1/2)(5) (3d '[3/2](1), 5d '[3/2](1), 5s '[1/2](1,) 7s '[1/2](1)) and 3p(3/2)(5) (6d[1/2](1), 6d[3/2](1), 8s[3/2](1)), then excited by lasers to the autoionizing Rydberg series 3p(1/2)(5) np ' ([1/2](0,1), [3/2](1,2)) and nf '[5/2](2). For the intermediate states of 5s ', 7s ', and 8s, the np ' ([1/2](0) and [3/2](2)) series are observed with high intensity but not the np ' ([1/2](1) and [3/2](1)) series when the polarization vectors of two light beams are in parallel; but when they are in orthogonal, the np '[1/2](0) series disappears, the np '[3/2](2) intensity remains, and the np ' ([1/2](1) and [3/2](1)) series show up strongly. The intensity distribution of the np ' series strongly depends on the intermediate state. The spectra of the np ' series are assigned according to their intensity variation with the polarization vectors. The quantum defects determined for the series np '[1/2](0)(n=11-57), np '[312](2)(n=11-65), np '[3/2](1)(n=11-31), and nf '[5/2](2)(n=9-74) are 1.611 +/- 0.011, 1.683 +/- 0.013, 1.688 +/- 0.010, and 0.016 +/- 0.005, respectively. Our values are in excellent agreement with theoretical prediction. The spectral line shapes of autoionizing Rydberg states are analyzed with a Beutler-Fano profile. Reduced autoionization linewidths for the np '[1/2](0)(n= 11-16) series vary in the range 2549-4145 cm(-1), and the nf '[5/2](2)(n=9-11) series in 186-247 cm(-1) in reasonable agreement with theoretical prediction.
Broadly tunable mW level UV light generated by intracavity SFG in a compact high-Q PPMgSLT OPO
(2007)
Tu, Shih-Yu
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Kung, A. H.
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Kurimura, Sunao
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Kitamura, Kenji
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Ikegami, Takeshi
A compact multi-kHz UV source tunable from 363nm to 378nm is realized by intracavity SFG in a PPMgSLT OPO. Phase-matched peaks at 334nm and 370nm are observed. A full tuning range of similar to 58nm is predicted. (C) 2007 Optical Society of America
Broadly tunable ultraviolet light generation in a compact MgO-doped periodically-poled stoichiometric lithium tantalate optical parametric oscillator with a high-Q cavity
(2008-11-01)
Tu, Shih-Yu
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Kung, A. H.
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Kurimura, Sunao
;
Ikegami, Takeshi
;
光電工程學系
A compact tunable UV laser source based on intracavity sum frequency generation in a MgO-doped periodically-poled stoichiometric lithium tantalate optical parametric oscillator is reported. UV output at an similar to 1 mW level of power over the range of 364 to 378 nm with a bandwidth of 0.5 nm was obtained with a crystal that has just one periodically-poled grating period. The full tuning range can be as much as similar to 68 nm, from 324 to 392 nm by varying the crystal temperature from room temperature to 250 degrees C. This will cover nearly the entire UVA range. (C) 2008 Optical Society of America
Carrier-Envelope-Phase Control of Ultrashort Periodic Pulses Synthesized from Raman Generated Combs
(2009-01-01)
Hsieh, Zhi-Ming
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Lai, Chien-Jen
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Chan, Han-Sung
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Wu, Sih-Ying
;
Lee, Chao-Kuei
The carrier-envelope phase of Raman generated ultrashort pulses is controlled by driving the Raman coherence with a beam at near the raman resonance frequency and its second harmonic.
Controlling the Carrier-Envelope Phase of Raman-Generated Periodic Waveforms
(2009-05-29)
Hsieh, Zhi-Ming
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Lai, Chien-Jen
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Chan, Han-Sung
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Wu, Sih-Ying
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Lee, Chao-Kuei
We demonstrate control of the carrier-envelope phase of ultrashort periodic waveforms that are synthesized from a Raman-generated optical frequency comb. We generated the comb by adiabatically driving a molecular vibrational coherence with a beam at a fundamental frequency plus its second harmonic. Heterodyne measurements show that full interpulse phase locking of the comb components is realized. The results set the stage for the synthesis of periodic arbitrary waveforms in the femtosecond and subfemtosecond regimes with full control.
Dissociation of heme from gaseous myoglobin ions studied by infrared multiphoton dissociation spectroscopy and Fourier-transform ion cyclotron resonance mass spectrometry
(2006-10-07)
Wang, Yi-Sheng
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Sabu, Sahadevan
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Wei, Shih-Chia
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Kao, C. -M. Josh
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Kong, Xianglei
Detachment of heme prosthetic groups from gaseous myoglobin ions has been studied by collision-induced dissociation and infrared multiphoton dissociation in combination with Fourier-transform ion cyclotron resonance mass spectrometry. Multiply charged holomyoglobin ions (hMb(n+)) were generated by electrospray ionization and transferred to an ion cyclotron resonance cell, where the ions of interest were isolated and fragmented by either collision with Ar atoms or irradiation with 3 mu m photons, producing apomyoglobin ions (aMb(n+)). Both charged heme loss (with [Fe(III)-heme](+) and aMb((n-1)+) as the products) and neutral heme loss (with [Fe(II)-heme] and aMb(n+) as the products) were detected concurrently for hMb(n+) produced from a myoglobin solution pretreated with reducing reagents. By reference to E-a=0.9 eV determined by blackbody infrared radiative dissociation for charged heme loss of ferric hMb(n+), an activation energy of 1.1 eV was deduced for neutral heme loss of ferrous hMb(n+) with n=9 and 10. (c) 2006 American Institute of Physics.
EUV continuum from compressed multiple thin plate supercontinuum
(2016)
Huang, P. C.
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Lu, C. H.
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Chen, B. H.
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Yang, S. D.
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Chen, M. -C.
A one-cycle (3.3fs) pulse compressed from multiple thin plates generated supercontinuum has been demonstrated and used to produce a bright EUV continuum covering from 43 to 65 eV with high up-conversion efficiency of 5x10(-5).
Fabrication of PPLT Crystal Fiber by the Method of Laser Heated Pedestal Growth
(2007-01-01)
Tai, Ta-Min
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Pei, Shan-Chuang
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Lee, Li-Min
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Huang, Sheng-Lung
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Kung, A. H.
The fabrication of a periodic poled Lithium Tantalate single crystal fibers were firstly achieved in-situ via the laser heated pedestal growth method. The spectrum of second harmonic generation was characterized. (C) 2007 Optical Society of America
Full Control of the Carrier-Envelope Phase of Raman-Generated Single-Cycle Waveforms
(2009-01-01)
Hsieh, Zhi-Ming
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Lai, Chien-Jen
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Chan, Han-Sung
;
Wu, Sih-Ying
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Lee, Chao-Kuei
Precise control of the carrier-envelope phase of Raman genearated ultrashort pulses is achieved by generating a Raman frequency comb using an infrared laser pulse and its second harmonic to drive the Raman coherence. (C) 2009 Optical Society of America
Generation of multi-octave-spanning laser harmonics by cascaded quasi-phase matching in a monolithic ferroelectric crystal
(2009-11-15)
Hsu, Wei-Chun
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Lai, Ying-Yao
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Lai, Chien-Jen
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Peng, Lung-Han
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Pan, Ci-Ling
We report the generation of the second to the sixth harmonics of a fundamental frequency covering two and a half octaves in a multiply-periodically poled lithium tantalate crystal by cascaded quasi-phase-matched frequency mixing. A frequency comb that is composed of these harmonics will permit the synthesis of a train of periodic subcycle subfemtosecond pulses in a compact setting. (C) 2009 Optical Society of America
Generation of Octave-Spanning Multiple Harmonics for Ultrafast Waveform Synthesis
(2009)
Hsu, Wei-Chun
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Hsieh, Zhi-Ming
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Lai, Ying-Yao
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Lai, Chien-Jen
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Chen, Wei-Ting
Up to seven laser harmonics covering more than two octaves in frequency have been generated efficiently in a single PPLT crystal. permitting the syntehsis of 1.5 femtosecond pulses in a stable and compact setting
Generation of tunable blue-green light using ZnO periodically poled lithium niobate crystal fiber by self-cascaded second-order nonlinearity
(2007-08-01)
Lee, Li-Min
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Pei, Shan-Chuang
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Lin, Der-Fong
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Chiu, Po-Chun
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Tsai, Mon-Chang
Using a novel self-cascaded first-order second-harmonic generation (SHG) and third-order sum-frequency generation (SFG) in a ZnO periodically poled lithium niobate crystal fiber, tunable blue-green light was demonstrated. At a domain pitch of 15.45 mu m, the SHG signal and its fundamental signal at 1423.9 nm can satisfy the third-order SFG quasi-phase-matched (QPM) condition. The measured SHG power at 714.2 nm was 12.25 mW under 100 mW input power, and the estimated nonlinear coefficient (d(33)) achieved was 25.3 pm/V. The self-cascaded SHG+SFG power measured at 477.1 nm was similar to 700 mu W under 350 mW input power. The maximum internal efficiency of the SHG is 14.84%. The tuning range of the self-cascaded SHG and SFG generated tunable blue-green light was more than 40 nm, from 471.3 to 515 nm. The maximum simulated 3 dB bandwidth achieved using a gradient-period QPM structure is 196 nm, which is from 1476 to 1672 nm. The gain-bandwidth product of the self-cascaded SHG and SFG processes decreases drastically as the bandwidth is broadened. (c) 2007 Optical Society of America.
Green-pumped high-power optical parametric oscillator based on periodically poled MgO-doped stoichiometric LiTaO3
(2006-12-15)
Tu, Shih-Yu
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Kung, A. H.
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Gao, Z. D.
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Zhu, S. N.
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Kurimura, Sunao
A high-power 532 nm-pumped multikilohertz nanosecond optical parametric oscillator using a periodically poled 1.0 mol. % MgO-doped stoichiometric lithium tantalate crystal that could be operated from room temperature to 200 degrees C without damage is reported. A broad continuous tuning range from 855 to 1410 nM was achieved within a single domain period. Efficient operation of high peak power and watt level average power with a power conversion of 62.5% was measured. These results show that a high-resolution high average power visible tunable source can be realized. (c) 2006 Optical Society of America.
In-Ga-O based double-heater phase change memory cell
(2008)
Wang, S. -L.
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Chen, C. -Y.
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Hsieh, M. -K.
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Lee, W. -C.
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Kung, A. H.
We report a new type of phase-change materials based upon the compound of In-Ga-O. It is found to exhibit two-order of magnitude resistivity change between the high-resistive amorphous phase and the low-resistive cubic phase at a phase-change temperature similar to 250 degrees C. When the In-Ga-O is incorporated into a nonvolatile phase change memory (PCM) device with a double-heater (DH) structure, it exhibits an on/off resistance ratio of 1000 and cycling over 300 times which are superior to those observed on a single-heater (SH) PCM device. These results, together with a low bias point of 70 mu A at 6.5 volt and 1.5mA at 3.5 volt, respectively, for set/ reset operation of the DH-PCM device to the crystalline/amorphous state, suggest that In-Ga-O is a promising material candidate for low power application of PCM devices.
Monolithic red-green-blue laser light source based on cascaded wavelength conversion in periodically poled stoichiometric lithium tantalate
(2006-10-30)
Gao, Z. D.
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Zhu, S. N.
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Tu, Shih-Yu
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Kung, A. H.
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光電工程學系
A compact, pulsed, red, green, and blue laser source based on cascaded quasi-phase-matched wavelength conversion in two periodic superlattices set in tandem in a single stoichiometric LiTaO3 crystal and pumped by a laser source at 532 nm is reported. The white light equivalent flux obtained was 80 lm per 1 W input with a green to white light power conversion efficiency of > 30%. Unity power conversion is feasible in this monolithic approach. (c) 2006 American Institute of Physics.
Optical Interference in Nonlinear Photonic Crystals
(2008)
Lai, Chien-Jen
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Peng, Lung-Han
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Kung, A. H.
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光電工程學系
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Department of Photonics
We report a generalized quantitative analysis of the origin of optical interference in two-dimensional nonlinear photonic crystals. The results are verified by a second harmonic generation experiment in a 2-D periodically-poled LiNbO3 crystal. (c) 2008 Optical Society of America
Optical interference in nonlinear photonic crystals
(2007-11-01)
Lai, Chien-Jen
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Peng, L. -H.
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Kung, A. H.
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光電工程學系
;
Department of Photonics
A model to analyze the interaction of the parametric fields being generated in a two-dimensional nonlinear photonic crystal has been developed. The analysis provides details of the interference of the generated wave(s) both inside and in the region just outside the crystal. The results are verified by second-harmonic generation in a LiNbO3 crystal that has been poled with a tetragonal inverted domain structure. (c) 2007 Optical Society of America.
Phase-change memory devices based on gallium-doped indium oxide
(2009-03-16)
Wang, S. -L.
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Chen, C. -Y.
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Hsieh, M. -K.
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Lee, W. -C.
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Kung, A. H.
We report repetitive phase-change memory (PCM) activity via the high- to low-resistance state transition in gallium-doped indium oxide (Ga:InO) induced by nanosecond electric pulses. The amorphous-to-crystalline phase transition of Ga:InO is found to occur at a crystallization temperature of similar to 250 degrees C with an activation energy of 1.27 +/- 0.07 eV. At the phase transition, we observe a change in two orders of magnitude in the PCM-device resistance, which can be correlated with the formation of (211) and {222} crystallites of bixbyite cubic In(2)O(3). We ascribe the phase-change mechanism to the Joule heating effect in Ga:InO.
Pulse Shaper Assisted Characterization of Single-cycle Optical Pulses
(2009)
Hsieh, Zhi-Ming
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Lai, Chien-Jen
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Liang, Wei-Hong
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Tang, Tsung-Ta
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Chen, Wei-Jan
Shaper-assisted autocorrelation is developed to characterize single-cycle pulses. The correlation signal show significantly improved signal-to-noise ratio and thus accuracy in pulse characterization when compared to cross-correlation obtained by splitting the spectral components of the pulse. (C) 2009 Optical Society of America