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1.
Seed laser pulses with average power of 146 μW and pulse duration of 480 fs were amplified to 14.5 mW. The pulse duration was compressed to 260 fs using 6 m high concentration E3+ r -doped fiber under forward pumping. The amplified signal pulse energy was 0.691 nJ (corresponding to a peak power of 2 657.7 W) and the repetition rate was 20.84 MHz. Spectrum breakup was observed simultaneously. The spectrum of pulses amplified by 3 m E3+ r -doped fiber remains a single peak under different pump power. The amplified pulse duration was compressed abnormally with the increasing pump power using the backward pumping; that is, the amplified pulses were compressed with the increasing pump power under low pump power. When the pump power reached 38 mW, the shortest amplified pulse duration was 309 fs. With further increase in pump power, the amplified pulses began broadening, accompanied by a single peak spectrum under different pump power.  相似文献   

2.
Seed laser pulses with average power of 146 μW and pulse duration of 480 fs were amplified to 14.5 mW. The pulse duration was compressed to 260 fs using 6 m high concentration E3+r-doped fiber under forward pumping. The amplified signal pulse energy was 0.691 nJ (corresponding to a peak power of 2 657.7 W) and the repetition rate was 20.84 MHz. Spectrum breakup was observed simultaneously. The spectrum of pulses amplified by 3 m E3+r-doped fiber remains a single peak under different pump power. The amplified pulse duration was compressed abnormally with the increasing pump power using the backward pumping; that is, the amplified pulses were compressed with the increasing pump power under low pump power. When the pump power reached 38 mW, the shortest amplified pulse duration was 309 fs. With further increase in pump power, the amplified pulses began broadening, accompanied by a single peak spectrum under different pump power.  相似文献   

3.
The mechanism of femtosecond optical pulse generation in a self-starting Er3+-doped fiber ring soliton laser and experimental research results are discussed. Using the nonlinear polarization rotation effect of the fiber for sat-urable absorbers (and then self-amplitude modulation) which acts as the mode locking mechanism in an Er3+-doped fiber ring cavity laser, stable self-starting mode locking pulses have been generated. The shortest output pulse is 269 fs, with the central wavelength of 1,531 pm at the repetition rate of 21.37 MHz. The average output powen of the two terminators of the laser are 0.25 mW and 0.08 mW respectively. The threshold pump power which sustains the mode locking is 15 mW. Under high pump power, the laser works in a high order harmonic mode locking state. The mode locking pulse durations vs different cavity lengths are also studied. Project supported by Major Project of Chines: Academy of Sciences (No. KJ952-J1-705).  相似文献   

4.
The experiment of the generation and amplification of femetosecond Ti:sapphire laser pulse at high repetition rate is reported. The laser pulses with minimum pulsewidth 15 fs, maximum spectrum width of 80 nm, average power of 200 mW are generated from a home-built self-mode-locked Ti:sapphire laser. As a seed pulse which is selected from the oscillator, the laser pulse is further amplified by using chirped-pulse-amplification technology in a Ti:sapphire amplifier from which a kind of pulses with single-pulse-energy of 100 uj, pulsewidth after compressing of 50 fs at 5 kHz repetition rate are produced. The system design and experimental results are discussed. Project supported by the National “Climbing Project” of China.  相似文献   

5.
Amplified spontaneous emission (ASE) and its restraint in a femtosecond Ti: sapphire chirped-pulse amplifier were investigated. The noises arising from ASE were effectively filtered out in the spatial, temporal and spectral domain. Pulses as short as 38 fs were amplified to peak power of 1.4 MI. The power ratio between the amplified femtosecond pulse and the ASE was higher than 106: 1.  相似文献   

6.
Amplified spontaneous emission (ASE) and its restraint in a femtosecond Ti: sapphire chirped-pulse amplifier were investigated. The noises arising from ASE were effectively filtered out in the spatial, temporal and spectral domain. Pulses as short as 38 fs were amplified to peak power of 1.4 MI. The power ratio between the amplified femtosecond pulse and the ASE was higher than 106: 1.  相似文献   

7.
Highly efficient TW multipass Ti:sapphire laser system   总被引:2,自引:0,他引:2  
An efficient chirped-pulse amplification, Ti: sapphire laser system, has been developed using mainly domestic components. The gain-narrowing effect has been significantly overcome by shaping spectrum of seeding pulses. With a novel aberration-free stretcher and two stage multi-pass amplifiers, pulses with duration of 25 fs and 36-mJ energy have been obtained at 10 Hz repetition rate, using only less than 290 mJ green Nd:YAG pump energy. This corresponds to a 1.4 TW peak power and 32% main amplification efficiency. The energy stability of the laser systems is better than ± 3%.  相似文献   

8.
In the spaces E q(Ω), 1 < q < ∞, introduced by Smirnov, we obtain exact order estimates of projective and spectral n-widths of the classes W r E p(Ω) and W r E p(Ω)Ф in the case where p and q are not equal. We also indicate extremal subspaces and operators for the approximative values under consideration.  相似文献   

9.
Lipschitz equivalence of generalized {1,3,5}-{1,4,5} self-similar sets   总被引:1,自引:0,他引:1  
This paper investigates the Lipschitz equivalence of generalized {1,3,5}-{1,4,5} self-similar sets D=(r_1D)∪(r_2D (1 r_1-r_2-r_3)/2)∪(r_3D 1 r_3) and E=(r_1E)∪(r_2E 1-r_2- r_3)∪(r_3E 1-r_3),and proves that D and E are Lipschitz equivalent if and only if there are positive integers m and n such that r_1~m=r_3~n.  相似文献   

10.
Summary Let X be an irreducible smooth projective curve of genus g. Let d r (g) be the Brill-Noether Number. In this paper we prove some results concerning the schemes W d r of special divisors. 1) Suppose dim (W d–1 r )= d– 1 r (g)0 and d r (g) < g. If W d– 1 r is a reduced (resp. irreducible) scheme, then W d r is a reduced (resp. irreducible) scheme. 2) Under certain conditions, if Z is a generically reduced irreducible component of W d–1 r then Z W 1 0 is a generically reduced irreducible component of W d r . For r=1, we obtain some further results in this direction. 3) As an application of it we are able to prove some dimension theorems for the schemes W d 1 .  相似文献   

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