The “Katran” CO2 Laser with High Specific Output Power and Stable Parameters

The design and parameters of the UV-preionized discharge module Katran are described. A particular feature of the scheme is a high-voltage pulse formation technique for sharp discharge current ignition to stabilize the self-sustained glow discharge. The free-running laser based on the discharge module allows one to obtain high specific laser power exceeding 145 MW/liter in the P(20) line for the 10-m band for an active volume of 3 liters. Duration of the first spike of generation is 30 ns FWHM and energy content is about 65% of the total pulse energy. The high reliability and reproducibility of the module's operation for a wide range of parameters ensures laser suitability for different scientific and technical applications.     

Experiment for Photoabsorption of Low Z Ions Using Two Laser Produced Plasmas

Absorption spectroscopy is a fundamental technique for measuring quantities like inner-shell and double-electron excitations, photoionization, oscillator strength and autoionization, both for neutral and ionized atoms. Moreover, it is specifically useful for testing the validity of theoretical calculations of atomic or ionic structure. In spite of its importance, very little absorption spectroscopy of ionized species has been performed to this date, because of the difficulty in generating a suitably dense, stable and reproducible absorbing column of multicharged ions.     

Analysis of All-Optical State Generator for “Encoding a Qubit in an Oscillator”

The fault-tolerant quantum computation scheme proposed by Gottesman (Phys. Rev. A 64, 012310 (2001)) can be performed using relatively simple linear optical resources and provides a natural protection against arbitrary small errors. On the other hand, preparing the initial GKP states is a difficult task. A few proposals to generate GKP states have been done over the last years. Our objective here is to analyze the performance of a particular GKP generator that uses cat states, linear optical devices, squeezing, and homodyne detection. We use numerical simulations to study the behavior of the fidelity between the generated and the ideal states and show that the proposal in consideration is indeed a promising scheme.     

Nonlinear Dynamics of a Three‐Wave CO2 Laser with Loss Modulation

The nonlinear dynamics of a CO₂ laser having continuous electrical discharge pumping and loss modulation and generating in three vibrationalrotational lines of the same vibrational band is investigated theoretically. It is shown that it is possible to monitor the time and energy parameters of radiation in rather wide ranges by changing the depth and frequency of modulation and also the relationship between the constant components of losses. The character of the response of the threewave laser in loss modulation in one or two channels at certain parameters is similar to the response of a system with two degrees of freedom. In loss modulation simultaneously in three channels the response is equivalent to the response of a system with one degree of freedom.     

Electromotive force of a COCO2 sensor in COCO2H2H2O atmospheres and simultaneous determination of partial pressures of CO and CO2

The electromotive force (EMF) of the COCO₂ sensor using Na₂CO₃ and NASICON (Na₃Zr₂Si₂PO₁₂) as solid electrolytes has been examined in COCO₂Ar atmospheres. The EMF is related to the partial pressures of CO and CO₂ and proportional to log(P²_CO2P⁻¹_CO). The simultaneous use of the oxygen sensor of stabilized zirconia gives the EMF proportional to log(P_CO2P⁻¹_CO). The EMF's of two sensors permit to determine individually partial pressures of CO and CO₂. The existence of H₂ with high concentration does not affect the EMF's. This fact proves the applicability of the two-sensor system to the monitoring and the controlling of reducing atmospheres in industrial processes.     

The Experimental Study of a 100W Copper Vapor Laser

ＴｈｅＥｘｐｅｒｉｍｅｎｔａｌＳｔｕｄｙｏｆａ１００ＷＣｏｐｐｅｒＶａｐｏｒＬａｓｅｒＣＨＥＮＬｉｎＴＡＯＹｏｎｇｘｉａｎＹＩＮＸｉａｎｈｕａＷＡＮＧＲｅｎｗｅｎ（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＯｐｔｉｃｓａｎｄＦｉｎｅＭｅｃｈａｎｉｃｓ，Ｃ...     

Terahertz NH3 Laser with Optical Pumping by “Long” (~100 μs) Pulses of CO2 Laser for Plasma Diagnostics

Physics of Atomic Nuclei - A terahertz NH3 laser optically pumped by “long” (~100 μs) pulses of an electron-beam-sustained-discharge CO2 laser is demonstrated for the first time....     

Tunable Sum Frequency Mixing of a Ti∶sapphire Laser and a Nd∶YAG Laser

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｔｉ∶ｓａｐｐｈｉｒｅｌａｓｅｒｉｓｔｈｅｍｏｓｔｗｉｄｅｌｙｔｕｎａｂｌｅｌａｓｅｒｉｎｔｈｅｃｕｒｒｅｎｔｌａｓｅｒｔｅｃｈｎｏｌｏｇｙａｎｄｈａｓａｔｕｎｉｎｇｒａｎｇｅｆｒｏｍ 0 .68ｔｏ 1 .1 μｍ .Ｓｏｉｔｉｓ ｑｕｉｔｅｉｍｐｏｒｔａｎｔａｎｄｕｓｅｆｕｌｗｉｔｈｎｏｎｌｉｎｅａｒｏｐｔｉｃａｌｆｒｅｑｕｅｎｃｙｃｏｎｖｅｒｓｉｏｎｔｅｃｈｎｏｌｏｇｙｔｏｅｘｐａｎｄｉｔｓｏｕｔｐｕｔｗａｖｅｌｅｎｇｔｈ .Ｎｏｎｌｉｎｅａｒｗａｖｅｌｅｎｇｔｈｃｏｎｖｅｒ…     

Tunable Sum Frequency Mixing of a Ti∶sapphire Laser and a Nd∶YAG Laser

In this paper the theoretical and experimental results of sum-frequency mixing of a Ti∶sapphire laser and a 1.064 μm Nd∶YAG laser are presented. By using two KTP crystals cut at θ=76° and 85° (φ=90° in both crystals), respectively, the sum-frequency mixing tuning range from 459.3 to 509.6 nm in one Ti∶sapphire laser setup is experimentally achieved. The maximum output energy was 14.6 mJ and the energy conversion efficiency was up to 15.2%.     

Optimization and Comparing a Different Various of Head Part of a Moderator of “Central” Direction for IBR-2 Reactor

The performance of the upstream moderator for neutron beams 1, 4, 5, 6, and 9 extracted from the IBR-2 reactor is simulated towards selecting its optimum configuration. For different moderator options, gain factors with respect to the existing comb-shaped water moderator are computed. Taking into account the technological issues in manufacturing a combined moderator, the scheme with optimal physical characteristics is selected.     

Modulation Frequency Multiplexed Tunable Diode Laser Spectroscopy System for Simultaneous CO, CO2 Measurements

A modulation frequency multiplexed dual diode-laser system is developed for simultaneous detection of the two most common fire gas products CO and CO2. Simultaneous detection is achieved by modulating each laser at different frequencies, demodulating the signal by a pair of lock-in amplifiers for each gas. Laser beams are combined and detected by one detector after passing through an identical optical path. The experimental results show little performance degradation associated with modulation frequency multiplexing, and no cross-talk between the two multiplexed detection channels is measured.     

Proposal for Efficiency Enhancement of a Far Infrared Free Electron Laser

ＰｒｏｐｏｓａｌｆｏｒＥｆｆｉｃｉｅｎｃｙＥｎｈａｎｃｅｍｅｎｔｏｆａＦａｒＩｎｆｒａｒｅｄＦｒｅｅＥｌｅｃｔｒｏｎＬａｓｅｒ￥ＨＵＳｕｘｉｎｇ；ＦＵＥｎｓｈｅｎｇ；ＸＵＺｈｉｚｈａｎ（ＳｈａｎｇｈａｉＩｎｓｔｉｕｔｅｏｆＯｐｔｉｃｓａｎｄＦｉｎｅＭ...     

Theoretical Analysis on the Simultaneous Operation of a Color-Center Laser and a -Switched Nd∶YAG Laser

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　ＢｅｃａｕｓｅＬｉＦ∶Ｆ- 2 ｃｏｌｏｒ ｃｅｎｔｅｒｃｒｙｓｔａｌｈａｓｉｔｓｏｗｎｄｉｓｔｉｎｇｕｉｓｈｅｄｃｈａｒａｃｔｅｒｉｓｔｉｃｓ[1～ 5] ,ｉｔｈａｓｂｅｅｎｕｓｅｄａｓａｃｔｉｖｅｍｅｄｉｕｍｓ[4 ,6,7] ｏｒａｓｍｏｄｕｌａｔｅｄｅｌｅｍｅｎｔｓ[8,9] .Ｉｎｔｈｉｓｐａｐｅｒ,ｗｅｗｉｌｌｉｎｔｒｏｄｕｃｅａｎｏｔｈｅｒｋｉｎｄｏｆｕｓａｇｅ ,ｔｈａｔｉｓ ,ｉｔｉｓｕｓｅｄｂｏｔｈａｓａｎａｃｔｉｖｅｍｅｄｉｕｍｆｏｒｃｏｌｏｒｃｅｎｔｅｒｌａｓｅｒｔｕｎａ…     

A New Formula for the Spectra of Axial Symmetric and Transition Nuclei and a Quantity to Identify the Nuclear γ Deformation

The analytical limits of a speacial potential of the Bohr Hamiltonian are discussed in detail.A new formula for the axial symmetric,triakial deformed and the γ-soft nuclei is presented.The nuclear γ deformation can be identified with this formula.The calculations of some nuclear yrast lines seproduce the experiment al results very Well,and the degree of the nuclear γ deformation is obtained.     

Effects of Correlations Between the Real and Imaginary Parts of Quantum Noise on Intensity Fluctuation for a Single-Mode Laser

We study the effects of correlations between the real and imaginary parts of quantum noise on the intensity fluctuation for a single-mode laser. The analytic expressions of the intensity correlation function C(r) and the associated relaxation time Tc in the case of a stable locked phase resulting from the cross-correlation λq between the real and imaginary parts of quantum noise are derived by means of projection operator method. Based on numerical computations it is found that the presence of cross-correlations between the real and imaginary parts of quantum noise causes the intensity fluctuation to increase. A slowing-down phenomenon exists in the sense that Tc increases as a function of |λq|. Thus the decay o[ intensity fluctuation becomes slower.     

Analyses of Valid Range for the Linear Approximation in a Single-Mode Laser

Using the linear approximation method, we calculated the steady-state mean normalized intensity fluctuation for a loss-noise model of a single-mode laser driven by a pump noise and a quantum noise, whose real part and imaginary part are cross-correlated. We analyzed the valid range for the linear approximation method by studying the influences on the steady-state mean normalized intensity fluctuation by the cross-correlation coefficient, the intensities of the quantum and pump noise, the net gain, and the amplitude and frequency of the input signal, and we found that the valid range becomes wider when the cross-correlation between the real and imaginary part of quantum noise is weaker, the noise intensities of quantum and pump are weaker, the laser system is far from the threshold and the signal has smaller amplitude and higher frequency.     

Stationary Probability Distribution of Colored-noise Saturation Model for a Single-mode Dye Laser

１ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｓｔｕｄｙｏｆｄｙｎａｍｉｃａｌｓｙｓｔｅｍｓｐｅｒｔｕｒｂｅｄｂｙｎｏｉｓｅｉｓｒｅｃｕｒｅｎｔｉｎｍａｎｙｃｏｎｔｅｘｔｓｏｆｐｈｙｓｉｃｓ．Ｉｎｐａｒｔｉｃｕｌａｒ，ｉｎｔｈｅｃｏｎｔｅｘｔｏｆｍｏｒｅｒｅａｌｉ...     

Laser Stark spectroscopy of formaldehyde-d2: The Coriolis coupled ν4 and ν6 fundamentals

Using CO₂ and N₂O lasers, we have measured and assigned nineteen ν₄ and nine ν₆ rotation-vibration resonances of the type ΔM = 0 and M = J. These transitions were combined with the zero-field pure rotational spectra in order to determine the two fundamental vibrational frequencies, the rotational constants of both excited states, the Coriolis coupling constant, and the dipole moments of each of the three states. The ground-state rotational constants and centrifugal distortion constants were taken from a microwave study and the centrifugal distortion constants of the excited states were assumed equal to those of the ground state. The following results were obtained (standard deviations in parentheses):

     

20.

Octupole Strength of β-Stable and Drip-Line Nuclei     

ZHOU Xian-rong  WANG Nan  DONG Bao-Guo  Zhang Xi-zhen  ZHAO En-Guang 《理论物理通讯》2003,39(3):309-316

The octupole excitations of β-stable nucleus 20882 Pb126, a neutron skin nucleus 6200Ca40 and a drip-line nucleus 288O20 are studied by using the self-consistent Hartree-Fock calculation plus the random phase approximation (RPA) with Skyrme interaction. The lowest isoscalar (IS) excitation below threshold for nuclei 20882 Pb126 and 6020Ca40, and the IS and isovector (Ⅳ) giant resonances of nuclei 20882 Pb126, 6020Ca40 and 288 O20 can be well described by collective model. For skin nucleus 2600Ca40 and drip-line nucleus 288 O20, the low-lying unperturbed neutron octupole strength (△N ＝ 1) of transitions to non-resonant states are nearly unaffected and the transitions to bound states are absorbed into collective states by taking into account the RPA correlation.     

		$\text{ν}{}_4$		$\text{ν}{}_6$
$\text{ν}{}_0$		938.0345 (6)		989.2519 (18)		(cm?1)
$\text{A}$		139 579 (150)		143 323 (150)		(MHz)
$\text{B}$		31 873.6 (5)		32 379.5 (7)		(MHz)
$\text{C}$		26 242.9 (6)		25 994.4 (8)		(MHz)
$\text{ξ}{}_{64}{}^{\mathrm{(a)}}$			136 178 (770)			(MHz)
μ		2.319 (10)		2.347 (4)		(D)
μ(ground state)			2.3464 (8)			(D)

Octupole Strength of β-Stable and Drip-Line Nuclei

The octupole excitations of β-stable nucleus 20882 Pb126, a neutron skin nucleus 6200Ca40 and a drip-line nucleus 288O20 are studied by using the self-consistent Hartree-Fock calculation plus the random phase approximation (RPA) with Skyrme interaction. The lowest isoscalar (IS) excitation below threshold for nuclei 20882 Pb126 and 6020Ca40, and the IS and isovector (Ⅳ) giant resonances of nuclei 20882 Pb126, 6020Ca40 and 288 O20 can be well described by collective model. For skin nucleus 2600Ca40 and drip-line nucleus 288 O20, the low-lying unperturbed neutron octupole strength (△N ＝ 1) of transitions to non-resonant states are nearly unaffected and the transitions to bound states are absorbed into collective states by taking into account the RPA correlation.