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"Perkembangan teknologi menuntut pembaruan di berbagai bidang, salah satunya bidang keamaanan. Di antaranya, terdapat pengembangan pemanfaatan laser di dalam air. Dalam pengembangan sistem deteksi berbasis cahaya laser, diperlukan berbagai data mengenai sifat cahaya laser di dalam air yang mana akan diteliti dalam buku skripsi ini. Jenis laser yang digunakan adalah laser gas Helium-Neon dengan panjang gelombang 632 nm dan daya 30 mW. Penelitian dilakukan dengan menganalisis daya terukur dari laser sebelum dan setelah terjadi propagasi serta pemantulan pada akuarium yang berisikan air dengan berbagai tingkat salinitas. Hal-hal yang dikaji pada penelitian ini adalah karakteristik propagasi laser dan rugi-rugi daya laser. Tahap berikutnya adalah menyusun jaring-jaring laser dengan arah propagasi cahaya horizontal, tegak lurus dinding akuarium. Selanjutnya pada posisi terakhir berkas cahaya digunakan detektor LDR, yang menggunakan Arduino UNO sebagai mikrokontrolernya. Rangkaian tersebut memberikan peringatan berupa suara buzzer dan kedipan LED merah ketika jaring-jaring laser Helium-Neon tidak terdeteksi oleh LDR. Dari hasil eksperimen diperoleh bahwa rugi-rugi daya laser untuk jaring-jaring horizontal berkisar antara 33,16% sampai 73,19%; dengan rugi-rugi lebih tinggi terjadi ketika berkas laser berpropagasi menembus akuarium. Dari hasil perhitungan diperoleh nilai absorptivitas air dengan salinitas 35 ppt adalah 0,00962 L mol-1cm-1, nilai ini merupakan nilai dengan error terkecil pada perhitungan. Dengan pengembangan lebih lanjut, diharapkan hasil riset ini dapat diaplikasikan untuk membangun sistem pendeteksi obyek di dalam air.

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Technological developments demand updates in various fields, one of which is security. Among them is the development of the use of lasers in water. In developing a laser light-based detection system, various data regarding the properties of laser light in water are needed, which will be examined in this thesis. The type of laser used is a Helium-Neon gas laser with a wavelength of 632 nm and a power of 30 mW. The research was conducted by analyzing the measured power of the laser before and after propagation and reflection occurred in an aquarium containing water with various levels of salinity. In this work, the characteristics of laser propagation and laser power losses were studied, followed by the arrangement of the laser mesh with the light propagation direction horizontal, perpendicular to the aquarium wall. Furthermore, in the last position of the light beam, an LDR detector is used, which uses an Arduino UNO as the microcontroller. The circuit gives a warning in the form of a buzzer and red LED flashes when the Helium-Neon laser mesh is not detected by the LDR. From the experimental results, it was found that the laser power losses for horizontal mesh ranged from 33.16% to 73.19%; with higher losses occurring when the laser beam propagated through the aquarium. From the calculation results, the absorptivity value of water with a salinity of 35 ppt is 0.00962 L mol-1cm-1, this value is the value with the least error in the calculation. With further development, it is hoped that the results of this research can be applied to build an object detection system in water."

"Sejauh ini, pendeteksian objek di dalam air dilakukan dengan teknologi sonar yang memanfaatkan gelombang suara. Namun keterbatasan kecepatan rambat suara di dalam air menjadi penghambat perkembangan sistem deteksi di bawah air. Disisi lain cahaya dapat merambat lebih cepat di dalam air, selain itu laser memiliki sifat monokromatis dan koheren sehingga laser dapat mendeteksi objek dengan jarak yang cukup jauh dan dengan akurasi tinggi. Pada Skripsi ini dilakukan eksperimen untuk mengamati karakterisasi propagasi cahaya laser dengan λ = 532 nm sebagai dasar untuk mendeteksi objek di dalam air. Eksperimen dilakukan di berbagai tingkat salinitas air, untuk mewakili berbagai jenis air di alam. Selanjutnya dilakukan eksperimen dengan membuat jaring-jaring laser serta rangkaian pendeteksi sebagai sistem pendeteksi objek asing di dalam air dengan  memanfaatkan sensor fotodioda dan ESP32. Dari hasil eksperimen didapat nilai untuk absorptivitas berkas laser semikonduktor λ = 532 nm pada air garam dengan tingkat salinitas 35 ppt adalah sebesar 0,00415 L.

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So far, underwater object detection has been carried out using sonar technology that utilizes sound waves. However, the limited speed of sound propagation in the water is an obstacle for the development of underwater detection systems. On the other side, light can travel faster in water. In addition, the laser has monochromatic and coherent properties so that the laser can detect objects at a considerable distance and with high accuracy. In this thesis, an experiment was carried out to observe the characterization of laser light propagation with λ = 532 nm as the basis for detecting objects underwater. Experiments were carried out at various levels of water salinity, to represent the different types of water in nature. Furthermore, experiments were carried out by making laser nets and detection circuits as a system for detecting foreign objects underwater by utilizing photodiode sensors and ESP32. Based on the experimental results, it was found that the absorptivity of the semiconductor laser beam λ = 532 nm in salt water with a salinity level of 35 ppt was 0.00415 L."

"The T-S diagram of waters i s important to understand because useful to know the water mass origin of the local waters. Therefore it is need a better undestanding of T-S diagram dynamic of the waters...."

"Salinitas merupakan salah satu cekaman abiotik yang mengancam produksi padi di Indonesia. Dalam rangka mendukung program ketahanan pangan, BB-Biogen telah melakukan pengembangan varietas padi Ciherang toleran salinitas hingga generasi BC4F2 dan BC5F1. Tanaman generasi BC4F2 dan BC5F1 Ciherang-OsDREB1A selanjutnya memerlukan serangkaian pengujian. Pertama, penapisan toleransi terhadap salinitas tinggi untuk menyeleksi tanaman yang menunjukkan sifat toleran terhadap salinitas tinggi. Kedua, analisis molekuler yang mencakup analisis integrasi, ekspresi OsDREB1A, dan Southern blot. Hasil penapisan salinitas terhadap BC4F2 dan BC5F1 Ciherang-OsDREB1A selama 26 hari dengan EC akhir berkisar 18 mS/cm telah berhasil menyeleksi 134 individu putatif transgenik dari total 543 tanaman uji. Hasil analisis integrasi menggunakan primer hptII menujukkan 73 dari 134 tanaman putatif transgenik memiliki hasil positif hptII. Seluruh tanaman yang positif PCR hptII juga terdeteksi memiliki hasil positif PCR menggunakan primer kombinasi 35S-496-F/OsDREB1A-R, mengindikasikan kestabilan integrasi transgen tetap terjaga selama persilangan. Hasil analisis ekspresi OsDREB1A menunjukkan terdapat variasi level ekspresi OsDREB1A antar individu Ciherang transgenik. Hasil analisis Southern blot menunjukkan jumlah salinan T-DNA berjumlah sekitar 6--8 kopi. Galur terbaik berdasarkan hasil analisis molekuler adalah BC5F1-K14-23-3 dan BC4F2-K13-11-3.

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Salinity is one of the abiotic stresses that threaten rice production in Indonesia. In order to support the food security programs, BB-Biogen has started doing development of salinity tolerant rice varieties Ciherang up to BC4F2 and BC5F1 generations. BC4F2 and BC5F1 generations of Ciherang-OsDREB1A transgenic lines require a series of tests for verifying the salinity tolerance and stability of transgene integration. First, screening for selecting the Ciherang-OsDREB1A transgenic lines that revealed tolerance to high salinity. Second, molecular analysis that includes analysis of integration, OsDREB1A expression, and Southern blot. The screening result of Ciherang-OsDREB1A transgenic lines BC4F2 and BC5F1 for 26 days with final EC approximately 18 mS/cm, had been successfully selected 134 putative transgenic plants of a total 543 tested plants.

PCR analysis results showed that 73 of 134 putative transgenic plants had PCR positive using hptII-F/hptII-R primer. Plants were detected positive in PCR analysis using hptII-F/hptII-R primer were also positive in PCR analysis using specific primer 35S-496-F/OsDREB1A-R, indicating that the stability of the transgene integration is maintained during the crossing. The results of OsDREB1A expression analysis showed that there were variations in expression levels among individuals Ciherang-OsDREB1A transgenic lines. The results of Southern blot analysis showed that the T-DNA copy number around 6--8 copies. Best lines based on the results of molecular analysis is BC5F1-K14-23-3 and BC4F2-K13-11-3."

"ABSTRAKA compact, simple and low-cost transversely excited atmospheric (TEA) pressure ultraviolet nitrogen laser {337 nm) has been designed and constructed employing the conventional Blumlein circuit. The measured energy of the output pulse of 337 nm is around 80 -J at 25 kV of charging voltage and l atm operating gas pressure. The beam divergence is found to be 7.7 mrad horizontally and 1.5 mrad vertically. The energy output decreases slightly with increasing gas pressure and gas flow rate, while the beam divergence is relatively stable with respect to the same operating parameters."

"ABSTRACTObservation of fluorescence decay signal of condensed-state molecular samples in the time domain has proved very useful for its identification and analysis. In order to overcome the noise problem in the generally weak fluorescence signals a double-gated boxcar integrator has been designed and incorporated into a spectrometer. The design concept and the working principle of this spectrometer is presented along with detailed description of its subsystems. Performance of this spectrometer has been tested with well-known sample (rhodamine 6G) and the results are duely analyzed. Application of this spectrometer to the measurement of fluorescence spectrum and mean life time of an E. Cali bacteria sample is also described in this work."

"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

Recently, the Indonesian researchers have anticipated the research on photonic devices especially on semiconductor laser. According to the anticipation above, the scope of this research is on photonic devices particularly on design and performance fabrication of 1.55 um GaInAsPfInP semiconductor laser using intrinsic single-mode layers.

The semiconductor laser was designed using intrinsic single-mode layers that consist of 4 (four) layers i.e., 2 (two) waveguiding layers with 1,15 p.m, AMB (Anti Melt Back) layer with 1.3 pm, and active layer with 1.55 pm. The layers were growth by designing 0.17 pm waveguiding layer thickness, 0.1 pm active layer- and AMB layer thickness, respectively. The performance optimizing were on optical confinement factor of the single-mode layers and threshold current.

The design and simulation results that threshold current of 702,5 mA and the optical confinement factor of 0.801 can be achieved. In addition, the optimum performance was obtained with thicker AMB layer, thicker active layer, and thinner wave-guiding layers.

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ABSTRAKPara peneliti di Indonesia hingga saat ini telah mengantisipasi penelitian di bidang devais fotonik terutama diode laser semikonduktor. Penelitian pada tesis ini di bidang devais fotonik diutamakan pada rancang bangun dan simulasi unjuk kerja dari diode laser semikonduktor pada panjang gelombang 1,55 um dengan bahan GalnAs-PIInP menggunakan lapisan mode tunggal intrinsik.Pada rancang bangun dirancang suatu diode laser semikonduktor dengan lapisan mode tunggal yang terdiri dari empat buah lapisan GaInAsP masing-masing 2 buah lapisan pandu gelombang dengan panjang gelombang 1,15 µm, lapisan aktif dengan 1,55 gm, dan lapisan anti cair ulang (ACU) dengan 1.3 µm. Untuk penumbuhan dipilih lapisan pandu gelombang setebal 0,17 gm, lapisan aktif setebal 0,1 gm dan lapisan ACU setebal 0,1 gm. Dalam perancangan, parameter faktor perangkap cahaya dari lapisan mode tunggal dan besamya arus ambang memegang peranan penting untuk mengoptimalkan unjuk kerja.Hasil rancang bangun dan simulasi memperlihatkan bahwa unjuk kerja perhitungan dengan arus ambang sebesar 702,5 mA dan faktor perangkap cahaya lapisan mode tunggal sebesar 0,801 dapat dicapai. Selain itu optimalisasi unjuk kerja dapat diperoleh dengan cara mempertebal lapisan ACU, membuat lapisan aktif tidak tipis dan lapisan pandu gelombang tidak tebal."