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"Pada masa kini, sangat diharapkan adanya material semikonduktor yang mampu merealisasikan kebutuhan akan divais dioda laser yang dapat dioperasikan pada spektrum gelombang pendek (short-wavelength), serta aplikasi suhu dan daya tinggi. Semikonduktor-semikonduktor group III-Nitride seperti Aluminium Nitride (AIN), Galium Nitride (GaN), dan Indium Nitride (lnN) merupakan material- material yang cocok (tahan) dioperasikan pada suhu dan daya yang tinggi karena rnemiliki energi gap yang besar (wide direct band-gap semiconductor device). Dioda laser semikonduktor sebagai sumber cahaya koheren penting sekali untuk teknologi menulis dan membaca dengan kerapatan optik yang tinggi. Kebutuhan ini bisa dipenuhi dengan menggunakan divais multiquantum well (MQW) dioda laser yang berbasis pada paduan ternary group III-Nitride, InGaN/GaN/AlGaN.Pada Skripsi ini telah dilakukan perhitungan dan analisa struktur divais optimum Multi Quantum Well Diodal Laser InGaN/GaN/AlGaN pada λ =420 nm tanpa memperhitungkan piezoresistive (strain) eject, lateral current spreading, defect recombination, dan heavy doping dan diperoleh besar efisiensi kuantum ekstemal, ηext = 19, 2152 %, threshold current density, Jth =1,9 kA/cm2, dan daya keluaran, Pout = 56,7291 W."

"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."

"This book offers the reader a practical guide to the control and characterization of laser diode beams. Following a short introduction to the working principles of laser diodes, the book describes the basics of laser diode beams and beam propagation, including Zemax modeling of a Gaussian beam propagating through a lens. The core of the book is concerned with laser diode beam manipulations, collimating and focusing, circularization and astigmatism correction, coupling into a single mode optical fiber, diffractive optics and beam shaping, and manipulation of multi transverse mode beams. The final chapter of the book covers beam characterization methods, describing the measurement of spatial and spectral properties, including wavelength and linewidth measurement techniques. "

"This thesis describes the device physics of GaN-based laser diodes, together with recent efforts to achieve longer emission wavelengths and short-pulse emission. Experimental and theoretical approaches are employed to address the individual device properties and optimize the laser diodes toward the requirements of specific applications."

"ABSTRAKPada Skripsi ini akan dibahas analisa disain divais menggunakan laser dioda dan Heterojunction Phototransistor yang berfungsi sebagai Light to Light Transducer. Latar belakang teori dan prinsip kerja dari laser Diode dan Heterojunction Phototransistor serta disain transduser juga akan dibahas pada Skripsi ini. Transduser melakukan pendeteksian cahaya, mengubah besaran optis ke dalam besaran listrik, diperkuat dan oleh Laser Dioda dipancarkan lagi sebagai besaran optis yang juga telah diperkuat, koheren dan monokromatis. Transduser ini dapat didisain dengan integrasi langsung secara vertikal dan Laser Diode dengan Phototransistor berbahan GaAs dengan dimensi 210 x 290 m2 dan penguatan maksimal 250 kali. Perhitungan dan analisa dilakukan pada daerah operasi panjang Gelombang 0.8-1.3 μm dan daya input 0-100 μW. Model preliminary Rangkaian yang dianggap dapat mewakili karakteristik struktur divais yang dirancang juga dibahas untuk mempermudah menganalisa dan memperhitungkan karakteristik divais.

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"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. "