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Full-Text Articles in Engineering
External Cavity Mode-Locked Semiconductor Lasers For The Generation Of Ultra-Low Noise Multi-Gigahertz Frequency Combs And Applications In Multi-Heterodyne Detection Of Arbitrary Optical Waveforms, Josue Davila-Rodriguez
External Cavity Mode-Locked Semiconductor Lasers For The Generation Of Ultra-Low Noise Multi-Gigahertz Frequency Combs And Applications In Multi-Heterodyne Detection Of Arbitrary Optical Waveforms, Josue Davila-Rodriguez
Electronic Theses and Dissertations
The construction and characterization of ultra-low noise semiconductor-based mode-locked lasers as frequency comb sources with multi-gigahertz combline-to-combline spacing is studied in this dissertation. Several different systems were built and characterized. The first of these systems includes a novel mode-locking mechanism based on phase modulation and periodic spectral filtering. This mode-locked laser design uses the same intra-cavity elements for both mode-locking and frequency stabilization to an intra-cavity, 1,000 Finesse, Fabry-Pérot Etalon (FPE). On a separate effort, a mode-locked laser based on a Slab-Coupled Optical Waveguide Amplifier (SCOWA) was built. This system generates a pulse-train with residual timing jitter of
Metrology Of Volume Chirped Bragg Gratings Recorded In Photo-Thermo-Refractive Glass For Ultrashort Pulse Stretching And Compressing, Christopher Lantigua
Metrology Of Volume Chirped Bragg Gratings Recorded In Photo-Thermo-Refractive Glass For Ultrashort Pulse Stretching And Compressing, Christopher Lantigua
Electronic Theses and Dissertations
Chirped Bragg gratings (CBGs) recorded in photo-thermo-refractive (PTR) glass provide a very efficient and robust way to stretch and compress ultra-short laser pulses. These gratings offer the ability to stretch pulses from hundreds of femtoseconds, to the order of 1 ns and then recompress them. However, in order to achieve pulse stretching of this magnitude, 100 mm thick CBGs are needed. Using these CBGs to both stretch, and re-compress the pulse thus requires propagation through 200 mm of optical glass. This therefore demands perfect control of the glass homogeneity, as well as the holographic recording process of the CBG. In …
Ultra High Density Spectral Beam Combining By Thermal Tuning Of Volume Bragg Gratings In Photo-Thermo-Refractive Glass, Derrek Drachenberg
Ultra High Density Spectral Beam Combining By Thermal Tuning Of Volume Bragg Gratings In Photo-Thermo-Refractive Glass, Derrek Drachenberg
Electronic Theses and Dissertations
High power lasers with diffraction limited beam quality are desired for many applications in defense and manufacturing. A lot of applications require laser beams at the 100 kW power level along with divergence close to the diffraction limit. The figure of merit for a beam used in such applications should be radiance which determines the laser power delivered to a remote target. One of the primary limiting factors is thermal distortion of a laser beam caused by excessive heat generated in the laser media. Combination of multiple laser beams is usually considered as a method to mitigate these limitations. Spectral …
Cholesteric Liquid Crystal Photonic Crystal Lasers And Photonic Devices, Ying Zhou
Cholesteric Liquid Crystal Photonic Crystal Lasers And Photonic Devices, Ying Zhou
Electronic Theses and Dissertations
This dissertation discusses cholesteric liquid crystals (CLCs) and polymers based photonic devices including one-dimensional (1D) photonic crystal lasers and broadband circular polarizers. CLCs showing unique self-organized chiral structures have been widely used in bistable displays, flexible displays, and reflectors. However, the photonic band gap they exhibit opens a new way for generating laser light at the photonic band edge (PBE) or inside the band gap. When doped with an emissive laser dye, cholesteric liquid crystals provide distributed feedback so that mirrorless lasing is hence possible. Due to the limited surface anchoring, the thickness of gain medium and feedback length is …
Dispersion-Managed Breathing-Mode Semiconductor Mode-Locked Ring Laser, Bojan Resan
Dispersion-Managed Breathing-Mode Semiconductor Mode-Locked Ring Laser, Bojan Resan
Electronic Theses and Dissertations
A novel dispersion-managed breathing-mode semiconductor mode-locked ring laser is developed. The "breathing-mode" designation derives from the fact that intracavity pulses are alternately stretched and compressed as they circulate around the ring resonator. The pulses are stretched before entering the semiconductor gain medium to minimize the detrimental strong integrating self-phase modulation and to enable efficient pulse amplification. Subsequently compressed pulses facilitate bleaching the semiconductor saturable absorber. The intracavity pulse compression ratio is higher than 50. Down chirping when compared to up chirping allows broader mode-locked spectra and shorter pulse generation owing to temporal and spectral semiconductor gain dynamics. Pulses as short …
An Interactive Training Device Using A Laser Video Disc, Mary C. Bertrand
An Interactive Training Device Using A Laser Video Disc, Mary C. Bertrand
Retrospective Theses and Dissertations
The goal of this paper is to develop an interactive training system. Although the system developed was used to train tank gunners, the system concepts are generic in that they can be applied to many training scenarios. Applications of computer-based training systems are briefly discussed. The system concepts are defined and hardware and software subsystems are outlined. An architectural overview will precede a detailed discussion of subsystems.
Optimization Analysis For Alignment Criteria And Installation Of Gravity Flow Underground Pipe, Eugene N. Balter
Optimization Analysis For Alignment Criteria And Installation Of Gravity Flow Underground Pipe, Eugene N. Balter
Retrospective Theses and Dissertations
In 1982 the Business Roundtable prepared several reports which investigated various aspects of construction which posed significant research opportunities. Their findings placed piping construction in the group of activities categorized as having "highest potential" for improvements based on inefficiency, or construction difficulty and proportionate costs. It was estimated that over $1 billion could be saved annually if the difficulty in the piping industry was improved to only average of other areas. Further investigation into the piping area showed that the alignment process took 20% of the cycle time for installation and ranked either first or second as compared to other …
Computerized Displacement Data Analysis In Laser Speckle Photography, Bijan Chitsaz
Computerized Displacement Data Analysis In Laser Speckle Photography, Bijan Chitsaz
Retrospective Theses and Dissertations
Laser speckle photography is an experimental technique which provides a non-contract means for direct measurement of in-plane displacements of objects subjected to different loading conditions. It requires a camera system to record two images of the object that are illuminated with laser light on a high resolution film. The double-exposure film (specklegram) is a permanent record of the displacement information of the object. Point-by-point analysis of the specklegram will yield the displacement data, but requires considerable time to complete the data reduction. An automated data analysis system is developed and described in this report. He-Ne laser and computer-controlled translation stages …
On The Theory And Experimental Results Of A Sensitive Fiber Optic Laser Accelerometer, Steven C. Furlong
On The Theory And Experimental Results Of A Sensitive Fiber Optic Laser Accelerometer, Steven C. Furlong
Retrospective Theses and Dissertations
No abstract provided.
Statistical Fading Of A Spherical Optical Wave In Atmospheric Turbulence, Lorraine M. Locke
Statistical Fading Of A Spherical Optical Wave In Atmospheric Turbulence, Lorraine M. Locke
Retrospective Theses and Dissertations
A formula for the average fade time of the intensity of a spherical optical wave travelling through atmospheric turbulence is developed. The model employed involves isotropic, homogeneous statistics using a lognormal distribution for the channel. The analysis is based on the fact that the logarithm of the irradiance is normally distributed and uses the work of S. O. Rice who developed such an expression for a zero mean, Gaussian process. The analysis employs the covariance function and the Taylor frozen turbulence hypothesis which results in an expression for the autocorrelation function.
Application Of Optimization Techniques To The Optical Design Of A Laser Seeker, David William Allemeier
Application Of Optimization Techniques To The Optical Design Of A Laser Seeker, David William Allemeier
Retrospective Theses and Dissertations
This report describes the development of a computer model for the design of a laser seeker optical system. A laser seeker is a device that detects pulsed laser energy. The computer model is configured to design the seeker optics based on the following performance criteria: Sensitivity to laser energy, which can be related to target acquisition range; optical field of view; and seeker optics cross section area. The design is defined by four variables and a set of fixed parameters, and is configured using computer optimization with both a direct search and a random search being used. A superior design …