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"ABSTRAKTujuan dari eksperimen yang dilakukan adalah untuk menyelidiki hal-hal yang berkaitan dengan pembentukan plasma, yakni zat yang tersusun dari muatan-muatan listrik bebas berupa ion-ion positif dan elektron elektron negatif yang jumlahnya nyaris sama.Plasma yang digunakan dalam eksperimen terbentuk dari udara laboratorium yang di iradiasi dengan berkas laser energi tinggi ( IJ - 2J ) dalam sebuah chamber yang dilengkapi dengan suatu rangkaian listrik DC.Dengan memberikan beda tegangan tertentu antara dua elektrode yang berada dalam chamber, maka elektron-elektron dari plasma yang berada diantara kedua elektrode tersebut akan ditarik oleh elektrode positif dan menimbulkan arus listrik pada resistor yang ada dalam rangkaian. Besar arus listrik yang mengalir ini dapat ditentukan harganya dengan cara mengukur besar tegangan pada resistor menggunakan cathode ray oscilloscope.Chamber yang merupakan kotak tertutup berisi plasma yang diamati, dilengkapi dengan pengukur tekanan, dan di hubungkan ke sebuah pompa vakum.Dengan memvariasi besar tekanan udara dalam chamber, jarak antar elektrode, beda tegangan antara elektrode, maupun besar energi laser, dapat diperoleh harga besaran-besaran fisis yang diselidiki, juga korelasi-korelasi antara suatu besaran fists, dengan besaran fists lainnya.

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ABSTRACT

An investigation has been conducted on the formation of plasma generated by focusing an intense Laser radiation.

A high voltage from DC source is used to trigger electrical breakdown between two electrodes which an air of laboratory will be investigated.

The electrical breakdown caused by laser radiation observed by measuring the voltage of pick up resistor in the electrical circuit. The value of electric current flows in resistor can be calculated from the value of voltage, it expresses the amount of electrons flow from plasma. By variating air pressure in the chamber, distance between two electrodes, potential difference between two electrodes, and laser energy, we can find correlations between: air pressure versus breakdown probability, air pressure versus electron number density, Laser energy versus electron number density, electric field per pressure versus electron drift velocity, etc."

"A study was performed on a laser-induced shock wave plasma generated on high concentration Au-Ag-Cu alloys by a Q-switched Nd-YAG laser of 4.8 mJ under reduced air pressure of 2 Torr. It was found that the total emission intensity of the secondary plasma is proportional to the intensity of the primary plasma, Assuming linear proportionality between the intensity of the primary plasma and the number of atoms vaporized from the target, it is proposed that the quantitative analysis can be applied to the intensities of the analytical emission Iines normalized by the total intensity of the primary plasma. This experimental result demonstrated for each metal element shows an excellent linear relationship between the normalized emission line intensity and the content of corresponding element after primary plasma normalization."

"Mekanisme plasma yang dibangkitkan oleh Laser Nd-YAG pada sampel padat pada tekanan udara di bawah 1 Torr akan dilakukan. Dalam hal menganalisis sifat-sifat plasma ini akan dilakukan perbandingan dengan karakteristik plasma pada tekanan udara di atas 1 Torr. Eksperimen sementara menunjukkan bahwa sifat-sifat plasma pada tekanan di bawah 1 Torr mempunyai mekanisme yang lain dengan plasma pada tekanan tinggi. Plasma pada tekanan udara di bawah 1 Torr dapat diprediksi karena proses tumbukan sangat cepat sebaliknya pada tekanan tinggi karena proses gelombang kejut (shock wave). Eksperimen menunjukkan bahwa plasma pada tekanan udara 0,5 Ton mempunyai slop posisi fungsi waktu mendekati satu dan mempunyai cacah latar (background) yang rendah."

"ABSTRACT

Probing of the atmospheric parameters have been done by many scientists since a century ago up to present with various techniques. A simple system of laser radar without using any collimated beam but a reflected mirror as transmitter and a small cassegranian type (10.5 an in diameter) telescope as receiving was constructed to investigate the relative Mie backscattering coefficient by utilizing a nitrogen laser as a light source in the range of measurement bellow 1 Km. The backscattered light received by the receiving telescope is converted into electric current by photomultiplier and is shown and known as "A scope" display on an oscilloscope. SNR of the signal from photomultiplier was increased by using a boxcar integrator and its output could be recorded with XY recorder."

"ABSTRACTLaser induced thin film production (LITFP) technique was employed for making plumbum (Pb) thin film by nitrogen laser deposition in miniature scale. The energy of nitrogen laser operated at 12.5 kv, 90 torr was 3.5 mj with 5 ns pulse duration, thus producing peak power at around 0.7 MW. Pb plasma of 1 cm diameter was generated in each laser bombardment, producing thin film above the glass substrate. The thin film characteristics were measured by means of their thickness and surface morphology using scanning electron microscope (SEM). It was proved that there was a linear relationship between the number of laser shots and film thickness."

"Kopling antara amplifier permukaan miring dan fiber taper lens-ended diselidiki secara teori. Penelitian teori didasarkan pada model gelombang bidang tiga dimensi yang dihitung melalui pergeseran fasa akibat permukaan iring. Kopling diselidiki berkenaan dengan parameter-parameter berkas dari pandu gelombang amplifier lens-ended, dan juga berkenaan dengan posisi fiber. Terjadinya rugi-rugi kopling karena permukaan miring dan karena variasi dari uji lens yang terbaik, rugi untuk permukaan miring 10° ditemukan lebih kecil dari 0.5 dB dibandingkan amplifier permukaan normal.

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The coupling between angled-facet amplifiers and tapered lens-ended fibers is investigated theoretically. The theoretical investigation is based on a three-dimensional plane wave model which accounts for the phase differences introduced by the angled facets. The coupling is investigated with respect to the beam parameters of the amplifier wave guids and the tapered lens-ended fiber, and also with respect to the fiber position. For optimized lens radii the excess loss for 0l0° facet angle is found to be less than 0.5 dB compared to a normal facet amplifier."

"ABSTRACTThe frequency dobled Rd: YAG laser (532 nm/10ns, 15mj/pulse) uses a pulsed, frequency dobled; which provides a monochromatic, energy source with extremely high peak power and to has capability to develop of latent fingerprint on various surface. In the porous surfaces, this laser to has superiority, the compared with the development another methods, like powder and chemical method in latent fingerprint development. The high peak power of the laser causes Palmar sweat: contain a variety compounds, among them amino acids, oils, enzymes, vitamins and other chemicals with in the print to fluoresce. Some latent fingerprints will fluoresce in their natural state during exposure to this laser energy. The natural state fluorescing prints make can be documented and recording by high-resolution TV cameras and monitor for maximum sensitivity. The next step, the compare latent fingerprints products with visible impression by comparable instruments, see patterns of the friction ridges and be found same amount of their galton detail. "

"The purpose of this reserach is to find out the influence of laser shooting to the ovaries stem of eye,ablation of crab's eye to the level of egg's maruty,the diameter of eggs and the number of eggs scylla serrata....."