Yaacob Mat Daud

Dynamics expansion of laser produced plasma with different materials in magnetic field

The dynamics expansion of the plasma generated by laser ablation of different materials has been investigated. The dynamics and confinement of laser generated plasma plumes are expanding across variable magnetic fields. A Q-switched neodymium-doped yttrium aluminum garnet laser with 1064 nm, 8 ns pulse width and 0.125 J laser energy was used to generate plasma that was allowed to expand across variable magnetic within 0.1 – 0.8 T. The expansions of laser-produced plasma of different materials are characterized by using constant laser power. CCD video camera was used to visualize and record the activities in the focal region. The plasma plume length, width and area were measured by using Matrox Inpector 2.1 and video Test 0.5 software. Spectrums of plasma beam from different materials are studied via spectrometer. The results show that the plasma generated by aluminum target is the largest than Brass and copper. The optical radiation from laser generated plasma beam spectrums are obtained in the range of UV to visible light.

Improvement in ignition and simmer current supply into xenon flash lamp

This paper reports the development of triggering circuits of xenon flash lamp for solid‐state laser. The method used in this study is simmer mode series triggering. The ionization started by igniting the flashlamp by using voltage pulse of 5 kV with pulse duration 3 Ps. The simmer current is flow continuously through the flash lamp just after the gaseous breakdown in the flash lamp. The output of simmer current supply in this study is about 170 V with DC current of approximately 75 mA.

Angular Distribution of Cu Ions by Nd:YAG Laser Using Faraday Cups

The infrared radiation from Nd:YAG laser (1604 nm, 8ns, 125mJ, 15.6MW) is focused by IR lens (20cm) to irradiate Cu (99.99%) target in air. The angular distribution and arrival of ions are collected by Faraday Cups (FC). For anisotropic investigation, the cups are arranged at different positions (5cm and 10cm) from the target at different angles (5°, 30°, 45°, 60° and 90°) with respect to the normal on target surface. Faraday Cups are biased at -100V and the ion current signals are obtained on Tektronix TDS 3054B Digital Storage oscilloscope (500 MHz) through integrated circuit. The debris that deposited on FC is also characterized by SEM and EDX analysis. Metallurgical analysis of exposed FC provides evidences of Cu material on Faradays cup. Mass removal rate for copper target is also calculated. Maximum arrival rate of ions is observed at angle 5° and minimum ions flux is at angle 90° to normal on the target surface. The results show the plume is peaked strongly in forward direction. The laser matter interaction is good for the laser based ion sources generation, which can produce a collimated beam of ions because of forward peaking.

Prominent 946 lines induced from flashlamp pumped Nd: YAG rod

Spectroscopic properties of Nd:YAG laser rod pumped by a new developed flashlamp is investigated. A new power supply is constructed to power xenon flashlamp. A 1 at.% Nd:YAG laser rod is transversely pumped by the flashlamp and stabilized by a water cooling system operated at ambient temperature of 20°C. The absorption and emission spectrum of the flashlamp pumped Nd:YAG rod is analyzed via spectroscopy technique. The peak absorption line is identified to be at 882 nm. The dominant emission line obtained from transition 4F3/2→4I9/2 comprised of quasi three level laser at 938.5 and 946 nm with the corresponding cross section of 2.42×10−19cm2 and 3.04×10−19cm2 respectively. This cross section is found almost ten times greater than the usual one.

Optimization of output Q-switched Nd: YAG laser based on switching time

This paper reports the optimization of output Q‐switch Nd:YAG. A free running Nd:YAG laser was employed as source of light. KD*P crystal was utilized as a Pockels cell. Avalanche transistor pulser was designed to switch a high voltage power supply. The switching time was conducted via a control unit based PIC16F84A microcontroller. The pulser was able to switch the voltage within 3 ns. The optimum switching time of Q‐switching is obtained at 182.34 μs. The corresponding laser output is 40 mJ with pulse duration of 25 ns.

Study on the Effect of Q-Switched Nd:Yag Laser Interaction with Al in Variable Magnetic Field

Dynamic and confinement of laser generated Aluminum plasma plumes expanding across a variable magnetic field have been investigated. A Q-switched neodymium-doped yttrium aluminum garnet laser with 1064 nm and 8 ns pulse width was used to generate plasma that was allowed to expand across 0.1 - 0.8 T magnetic field. The expansion of laser- produced plasma is characterized using constant laser power and in variable magnetic field. A Pulnix CCD video camera was used to visualize and record the activities in the focal region. The horizontal and vertical expansions of plasma plume were measured by using Matrox Inspector 2.1 software. The results showed that the plasma is expanding vertically and horizontally with respect to the magnetic field. The Al plasma interaction produced spectrum in the range of UV to visible light.

High-speed photographic study on plasma induced by focusing IR laser

The aim of this paper is to diagnose the formation and the effect of plasma induced by focusing a Q- switched Nd:YAG laser. The laser was focused by two methods that are single lens and two lenses. The optical breakdown and the plasma formation were visualized using CCD camera in conjunction with the high-speed photography system. Sensitive paper was employed as target material. Single pulse laser was exposed on the target and the damage was examined by metallurgical method. The results obtained indicated that the size of plasma slightly increases with the laser energy. The configuration of the plasma was found in an ellipse shape and produced an irregular pattern of damage with a single lens technique. On the other hand an oval shape of plasma was appeared and symmetrical circular pattern of damage was generated with the two lenses system.