Browsing by Author "Tu, Shih-Yu"

Now showing 1 - 6 of 6

Autoionizing Rydberg series (np ', nf ') of Ar investigated by stepwise excitations with lasers and synchrotron radiation
(2008-08-01)
Lee, Yin-Yu
;
Dung, Tzan-Yi
;
Hsieh, Re-Ming
;
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
;
Kung, A. H.
;
Kurimura, Sunao
;
Kitamura, Kenji
;
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
;
Kung, A. H.
;
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
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
;
Sabu, Sahadevan
;
Wei, Shih-Chia
;
Kao, C. -M. Josh
;
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.
Green-pumped high-power optical parametric oscillator based on periodically poled MgO-doped stoichiometric LiTaO3
(2006-12-15)
Tu, Shih-Yu
;
Kung, A. H.
;
Gao, Z. D.
;
Zhu, S. N.
;
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.
Monolithic red-green-blue laser light source based on cascaded wavelength conversion in periodically poled stoichiometric lithium tantalate
(2006-10-30)
Gao, Z. D.
;
Zhu, S. N.
;
Tu, Shih-Yu
;
Kung, A. H.
;
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.