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"Tesis ini menguraikan pengembangan dan pengukuran standar frekuensi pada 88 THz yang didasarkan pada garis E dari transisi P(7) CH4. Untuk maksud tersebut kita menggunakan sebuah laser yang frekuensinya digeser menggunakan efek Zeeman untuk mencapai garis E dari CH4.Laser He-Ne yang digunakan dalam eksperimen ini dibangkitkan menggunakan pelepasan (discharge) RF, yang menghasilkan keluaran laser berderau rendah. Kesesuaian impedansi antara penguatan RF dan laser He-Ne dicapai dengan sangat efektif menggunakan sebuah trafo resonansi.Dari tiga komponen efek Zeeman hanya komponen a digunakan sebagai garis penguat laser dan dua komponen lainnya 6+ dan 7C ditapis oleh uap Methylbromide dan candela Brewster, sehingga laser RF He-Ne berosilasi pada frekuensi tunggal yang dapat diatur dan keluaran laser berderau rendah.Untuk meningkatkan rasio SIN dari pendeteksi spektrum garis absorpsi E, telah dikembangkan sistim dispersi tersaturasi menggunakan laser He-Ne bermode ganda. Sistim ini bekerja sebagai pendeteksi heterodyne internal untuk merekam frekuensi denyut (beat). Sistim ini memperbaiki rasio SIN mencapai faktor 4 sampai 5 kali.Dengan menggunakan sistim tersebut telah dilakukan pengamatan ketergantungan frekuensi pusat garis E terhadap parameter kerja seperti: power laser, lebar modulasi laser dan tekanan methane. Pergeseran frekuensi diukur menggunakan sistim Offset lock dengan komponen pusat dari hyperfineyang terurai sebagai referensi yang stabil. Diperoleh untuk perubahan parameter kerja tertentu pergeseran frekuensi pusat garis E dibatasi antara 100 dan 150 Hz. Juga telah diamati pergeseran frekuensi yang terbesar adalah karena tekanan methane.Untuk pengukuran frekuensi absolut dan garis E, laser Zeeman He-Ne distabilkan menggunakan sebuah sistim deteksi ganda yang unik, yang telah dikembangkan dalam percobaan Penentuan frekuensi absolut garis E dilakukan menggunakan rantai pengukuran frekuensi yang ber-phasa koheren, yang dihubungkan dengan jam Cs dari PTB. Sebagai hasil dari pengukuran ini diperoleh frekuensi pusat garis E :vE = 88 373 149 028 553 ± 230 Hz, ini menunjukkan penambahan ketelitian yang cukup berarti terhadap pengukuran sebelumnya.

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This thesis describes the development and measurement of a frequency standard at 88 THz, based on E-line of P(7) transition of CI-4 For this propose we use a He-Ne laser tuned by Zeeman effect to E-line.

The He-Ne laser used in this experiment is excited by RF-discharge, which gives a low noise laser output. The matching condition of the impedance between RF power amplifier and the He-Ne laser is achieved more effectively by using a resonator transformer.

From three components of the Zeeman effect only 6 component is used as the laser gain line in this experiment and the two a+, n components are suppressed by methylbromide vapour and Brewster window respectively, so that the E-line RF He-Ne laser oscillates at a single adjustable frequency with a low noise laser output.

To enhance the SIN ratio of the detection of the E-line absorption spectrum, a saturated dispersion system using a double mode RF He-Ne laser have been studied and developed. This system works as an ideal internal heterodyne detector for recording the beat frequency. As a result the SIN ratio is improved by a factor of 4 to 5 times.

Employing this detection system has been carried out to study the dependency of the E-line center frequency on the operating parameters such as the laser power, the laser modulation width and the methane pressure. The frequency shift was measured by using an offset lock system with respect to the center component of the hyperfine resolved F2 -line as a stable reference. It was found that within the variation range of the operatings parameters the center frequency shift of the E-line, was limited between 100 and 150 Hz. It was also observed that the largest frequency shift was due to methane gas pressure.

For measurement of the absolute frequency of the E-line, the Zeeman tuned He-Ne laser was stabilized using an unique double detection system, which was developed in this work. The determination of the absolute frequency of the E-line was carried out using a phase coherent frequency measurement chain linked to a Cs clock of PTB. As the result of this measurement the E-line center frequency of CH4 was found to be:

vE = 88 373 149 028 553 ± 230 Hz and this result shows a substantial increasing accuracy over the previous measurements."

"ABSTRACTThe principles of frequency stabilization is to keep constant the optical path length in laser cavity by controlling the laser- tube length. In this system used temperature servo control to control the laser tube length.As reference to an error derived by a sensitive frequency discriminator. Basically the operation of this sensitive frequency discrimantor utilized the longitudinal Zeeman Laser, which splits atomic gain profile.When a longitudinal magnetic field is applied to an internal mirror of single mode He-Ne Laser, the active medium acquires a negative circular dichroism. There fore the intensity of the left cicular polarization (LCP) output of the, laser will be different from the intensity of the right circular polarization (RCP) output and only when the two are simmetrically disposed about the center line will their intensities be equal. This intensity difference as feedback can be detected by passing the output beam throught Wallaston prism and the two orthogonally polarized beams are received by two identical photodiodes. The difference between the output of photodiode as amplified and the resulting signal is passed throught a system controller (PID) before it is fed back as heating or cooling current of peltier elements. This current controls the resonator length thermally and lock the laser frequencies of the two polarized beam symmetrically on either side of the profile."

"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....."

"Telah dilakukan pembangkitan plasma sekunder hasil interaksi antam laser Nd-YAG (2 mJ, 8 ns) pada moda Q-swicthed dengan target kuningan dan tembaga di udara tekanan rendah (-2 Tort). Karakterisasi plasma dilakukan dengan teknik distrilbusi ruang cacah-waktu dan seluruh-waktu. Hasilnya menunjukkan bahwa plasma gait-wider berbentuk hemispherik dengan diameter 8' mm, dan crater yang terjadi pada target memiliki diameter sekitar 20 mm. Efek penguapan selektif dapat ditekan dengan menurunkan energi laser dari 80 mJ ke 2 mJ. Pengukuran temperatur sebagai fungsi tekanan gas penyangga menunjukkan bahwa temperatur plasma tetap tinggi berkisar 6500 K Juga didapatkan kenyataan bahwa intensitas emisi backgroundnya sangat rendah, dan perbandingan sinyal ke background (SIB) cukup tinggi yaitu 8000 kali. Adapun plasma sekunder yang terjadi dibangkitkan oleh mekanisme gelombang kejut dan mekanisme eksitasi tumbukan sangat cepat antra atom-atom chili target dengan molekul-molekul gas penyangga."