Effects of Confined Laser Ablation on Laser Plasma Propulsion

We investigate the effects of confined laser ablation on laser plasma propulsion. Compared with planar ablation, the cavity ablation provides an effective way to obtain a large target momentum and a high coupling coefficient. When laser pulses are focused into a cavity with 1 mm diameter and 2ram depth, a high coupling coefficient is obtained. By using a glass layer to cover the cavity, the coupling coefficient is enhanced by 10 times. Meanwhile, it is found that with the increase of the target surface size, the target momentum presents a linear increase.     

Pedestal Measurement of Laser Pulses

ＰｅｄｅｓｔａｌＭｅａｓｕｒｅｍｅｎｔｏｆＬａｓｅｒＰｕｌｓｅｓＷＡＮＧＹｉｍｉｎＺＨＡＮＧＺｈｅｎｇｑｕａｎＸＵＺｈｉｚｈａｎ（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＯｐｔｉｃｓ＆ＦｉｎｅＭｅｃｈａｎｉｃｓ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅ...     

Picosecond Pulse Laser Microstructuring of silicon

We report the experimental results of picosecond pulse laser microstructurlng (pulse duration 35 ps, wavelength 1.06μm, repetition rate 10 Hz) of silicon using the direct focusing technique. Arrays of sharp coldcal spikes located below the initial surface have been formed by cumulative picosecond pulsed laser irradiation of silicon in SF6. Irradiation of silicon surface in air, N2, or vacuum creates ripple-like patterns, but does not create the sharp conical spikes.     

Characteristics of Tellurite Neodymium-doped Glass Laser

ＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＴｅｌｌｕｒｉｔｅＮｅｏｄｙｍｉｕｍ－ｄｏｐｅｄＧｌａｓｓＬａｓｅｒ￥ＸＵＢｉｎｇ；ＬＥＩＮｉｎｇ；ＷＵＪｉａｎｇｕａｎｇ；ＺＨＡＮＧＺｈｅｎｑｕａｎ；ＸＵＺｈｉｚｈａｎ（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＯｐｔ...     

Intensity Moments of Hermite-Cosh-Gaussian Laser Beams

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｉｎｒｅｃｅｎｔｙｅａｒｓ ,ａｎｉｎｔｅｒｅｓｔｉｎｇｓｏｌｕｔｉｏｎｏｆｔｈｅ ｐａｒａｘｉａｌｗａｖｅｅｑｕａｔｉｏｎ ,ｋｎｏｗｎａｓｔｈｅＨｅｒｍｉｔｅ ｓｉｎｕｓｏｉｄａｌ Ｇａｕｓｓｉａｎ (ＨＳＧ )ｂｅａｍｓ,ｈａｓｂｅｅｎｉｎｔｒｏｄｕｃｅｄｂｙＣａｓｐｅｒｓｏｎａｎｄＴｏｖａｒ[1,2 ] .ＡｓｏｎｅｏｆｔｈｅｓｐｅｃｉａｌｅｘａｍｐｌｅｉｎＨＳＧｆａｍｉｌｙ ,ｔｈｅＨｅｒｍｉｔｅ ｃｏｓｈ Ｇａｕｓｓｉａｎ(ＨＣｈＧ)ｂｅａｍｓ′ｓｆｉｅｌｄｄｉｓｔｒｉｂｕｔｉ…     

Experimental Quantum Teleportation of Laser Beams

We experimentally demonstrate quantum teleportation for continuous variables by using squeezed-state entanglement. A fidelity expression for a real experimental system is presented, where all the imperfection factors are considered, including losses and phase fluctuations. The measured fidelity for input coherent states is 0.62 and the prospective result with our measured entanglement and efficiencies is 0.69. We will show the details of the quantum teleportation for continuous variable and discuss the problems for further improvement in this experiment.     

Wavelengths of Five Ni-Like Laser Lines

ＷａｖｅｌｅｎｇｔｈｓｏｆＦｉｖｅＮｉ－ＬｉｋｅＬａｓｅｒＬｉｎｅｓ￥Ｇ．Ｘ．Ｃｈｅｎ；Ｑ．Ｙ．Ｆａｎｇ；Ｗ．Ｃａｉ（ＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄＰｈｙｓｉｃｓａｎｄＣｏｍｐｕｔａｔｉｏｎａｌＭａｔｈｅｍａｔｉｃｓＰ．Ｏ．ＢＯＸ８００９Ｂｅｉ...     

Laser induced fluorescence of CdHg excimer

The fluorescence of CdHg excimer has been observed over the spectral range 220-320 nm for temperature between 660-820K. The spectra were excited in a Cd-Hg mixture contained in a quartz vapor cell by laser pulses at 326.1nm. The peaks of these bands are at about 232, 256 and 286 nm respectively. An interpretation has been given out according to the potential-energy curves.     

Study on Laser Conditioning of Optical Coatings

ＳｔｕｄｙｏｎＬａｓｅｒＣｏｎｄｉｔｉｏｎｉｎｇｏｆＯｐｔｉｃａｌＣｏａｔｉｎｇｓ￥ＺＨＡＯＱｉａｎｇ；ＦＡＮＺｈｅｎｇｘｉｕ；ＷＡＮＧＺｈｉｊｉａｎｇ（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＯｐｔｉｃｓａｎｄＦｉｎｅＭｅｃｈａｎｉｃｓ，Ｃｈｉｎｅｓ...     

Laser Phase Relations of High-Order Harmonic Generation

Laser phase relations of high-order harmonic generation （HHG） are calculated with the saddle point theory. The results show a two-peak structure including a symmetric and an asymmetric temporal distributions of the instantaneous frequency of HHG radiation. These distributions are fitted with Gaussian and polynomial functions, respectively. Two calculation formulae are presented to analyse attosecond x-rays with specified time duration and energy bandwidth in experiments.     

Development of New Nephelometer with Diode Laser

ＤｅｖｅｌｏｐｍｅｎｔｏｆＮｅｗＮｅｐｈｅｌｏｍｅｔｅｒｗｉｔｈＤｉｏｄｅＬａｓｅｒＦＡＮＳｈｉｆｕＳＵＮＺｈｅｎｄｏｎｇＺＨＡＯＹｕｃｈｕｎ（ＤｅｐａｒｔｍｅｎｔｏｆＢｉｏｍｅｄｉｃａｌＥｎｇｉｎｅｒｉｎｇ＆ＳｃｉｅｎｔｉｆｉｃＩｎｓｔｒ．，Ｔｉａ...     

Experimental Investigation of an L-Shaped Very-Small-Aperture Laser

An L-shaped very-small-aperture laser （VSAL） with high power output and field enhancement effect is fabricated and characterized. As a comparison, a conventional rectangular VSAL and a double-aperture VSAL containing one L-aperture and one rectangular aperture are also fabricated and measured. The confined optical fields in the vicinity of apertures of VSAL are detected using an apertured near-field scanning optical microscope. The experimental results reveal that the power output from the L-shaped VSAL increases about 13 times than the rectangular VSAL with a comparable aperture area. It is indicated that the L-shaped VSAL has strong power output enhancement effect. The near-field distribution of the double-aperture VSAL indicates that the L-aperture has the field confinement and enhancement effect stronger than the rectangular aperture.     

Ablation of GaN Using a Femtosecond Laser

We study the pulsed laser ablation of wurtzite gallium nitride(GaN) films grown on sapphire,using the femtosecond laser beam at a central wavelength of 800nm as the source for the high-speed ablation of GaN films.By measuring the backscattered Raman spectrum of ablated samples,the dependence of the ablation depth on laser fluence with one pulse was obtained.The threwshold laser fluence for the ablation of GaN films was determined to be about 0.25J/cm^2,Laser ablation depth increases with the increasing laser fluence until the amount of removed material is not further increased.The ablated surface was investigated by an optical surface interference profile meter.     

Experiment Study of LD Pumped Solid State of Dual-Frequency Laser

1 Introductionace--pumped SOlid-state laser (DPSL) have given rise to an attractive researchinterest and become one of the research focus in the field of laser due to theiradvantageS, such as high efficiency, compactness, steadiness, lOng lifetime and allsolldstate construction. The dual--frequency laser belongs tO the rather complex andadVanced techniqUe. It is applied widely in precise interferometry, laser ranger, laserradar, and heterodyne vibrometry.At present, there are lotS of pape…     

The Carrier-Envelope Phase of Focused Few-Cycle Laser Pulses

The Gouy phase shift modulates the carrier-envelope phase of a focused few-cycle laser pulse. We investigate the variations of the carrier-envelope （CE） phase of a pulsed Gaussian beam on and off the axis by the first-order approximation and numerical calculation. The CE phase undergoes a π shift from minus infinity to infinity, and it changes fastest with distance at the focus. The variation of CE phase on propagation distance is nearly independent of pulse duration At when At is greater than lO fs and the first order approximation fits this result very well. The maximum difference of CE phase between a pulse with duration of one cycle and the result of first-order approximation is 0.09.     

Quasi–Stationary Regime of Ring Laser Generation

An exact solution to the equations that describe the operation of a ring laser having nonstationary parameters is obtained. An iterative formula is derived and the conditions under which a quasi–stationary solution can be used are determined. Lasers with vibrating and reversing differences of the frequencies of opposite waves are considered. In the case of a reversing shift, it is always possible to isolate a quasi–stationary regime when transient processes are completed.     

Laser induced self-propagating high-temperature synthesis of TiNi alloy

TiNi alloy, especially porous TiNi, a good biocompatible material, can be made by laser induced self-propagating high-temperature synthesis (SHS). A 40-W CO2 laser was used to ignite the powders of Ti and Ni, and TiNi intermetallic compound was synthesized by SHS in a reaction kettle of stainless steel. High-speed photography, X-ray diffraction, and scanning electron microscopy were used to investigate and analyze the reaction process, phase composing, and microstructure of the product, respectively. The influence factors on the reaction process and the product were discussed. The results indicate that laser induced SHS is an efficient, energy-saving method; The phase ingredient of the product consists of TiNi, Ti2Ni, and Ni3Ti. With the increase of the preparing pressure of the sample, the reacting rate decreases; With the increase of the laser power and the preheating temperature, the reacting rate increases. Under the condition of 30℃/min, the synthesis reaction had been carried out consistently and     

Laser effect on the tissue culture of rice

We treated the callus of high-quality Yunan rice DR453 by He-Ne laser, then found the seedling of these callus emerging to an earlier date and the green seedlings differentiation rate is much higher than that of the callus not treated with laser (CK). It is useful to research the breeding on the tissue culture.     

Study on Laser Welded Strength of Cemented Carbide

１ＩｎｔｒｏｄｕｃｔｉｏｎＬａｓｅｒｗｅｌｄｉｎｇａｓａｎｅｗｔｅｃｈｎｏｌｏｇｙｈａｓｒａｐｉｄｌｙｄｅｖｅｌｏｐｅｄ．Ｔｈｅｌａｓｅｒｄｉｐｓｏｌｄｅｒｉｎｇｃａｎｗｅｌｄｃｅｍｅｎｔｅｄｃａｒｂｉｄｅｗｉｔｈｓｔｅｌｔｏｇｅｔｈｅｒａｎｄｆｏ...