Alan Arai - Academia.edu (original) (raw)

Papers by Alan Arai

Research paper thumbnail of Automatic Vehicle Steering Using a Fixed Orientation Distance Feedback Sensor

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Automatic Vehicle Steering Using a Fixed Orientation Distance Feedback Sensor

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Automatic Vehicle Steering Using a Fixed Orientation Distance Feedback Sensor

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A Theoretical and Experimental Study on Vehicle Lateral Control

The results of an experimental work on the lateral control of a full-scaled vehicle are reported ... more The results of an experimental work on the lateral control of a full-scaled vehicle are reported in this paper. Two control algorithms were tested, a simple PID controller to serve as the baseline, and an optimal preview controller, which was developed to improve the tracking performance, ride quality and robustness of the system. The theoretical development and the experimental setup are briefly discussed, followed by some experimental results.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Laser ablation threshold and etch rate comparison between the ultrafast Yb fiber-based FCPA laser and a Ti:sapphire laser for various materials

Ti:Sapphire lasers remain the most widely used utlrafast laser. However, precise optical alignmen... more Ti:Sapphire lasers remain the most widely used utlrafast laser. However, precise optical alignment and environmental control are necessary for continuous, long-term stable operatoin of the laser. IMRA's FCPA laser is an air-cooled, Yb fiber-based ultrafast laser designed to operate in an industrial environment and provide a stable, high-quality laser beam. In this work, the micromachining performance of the FCPA laser is directly compared with a conventional Ti:Sapphire regenerative amplifier laser. An experimental study was conducted to determine the ablation threshold and etch rate for a variety of materials (including metals, semiconductors, and dielectrics). The materials chosen for the experiments cover a wide range of optical, mechanical and physical properties. Similar focusing conditions were used for both lasers in order to ensure that any differences in the results are primarily due to the different characteristics of each laser. For materials with a relatively low ablation threshold, the full energy of the Ti:Sapphire laser is not needed. Furthermore, it is near the ablation threshold where ultrafast laser processing provides the benefit of minimal thermal damage to the surrounding material. Although the relatively low pulse energy of the FCPA limits its ability to ablate some harder materials, its high repetition rate increases the material processing speed and its good beam quality and stability facilitates tight, efficient focusing for precise machining of small features.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Ultrashort pulse micromachining with the 10-muJ FCPA fiber laser

IMRA's ultrashort pulse fiber laser products continue to evolve to expand the application scope. ... more IMRA's ultrashort pulse fiber laser products continue to evolve to expand the application scope. The latest prototype FCPA produces pulses with less than 500-fs pulse duration at a 50-kHz repetition rate. At the fundamental wavelength of 1045 nm, the pulse energy is greater than 10 mJ. The increase in pulse energy over the standard FCPA μJewel permits greater flexibility in the focusing conditions applicable for micromachining, enabling a wider variety of laser-machined structures and profiles. This paper describes the latest micromachining application areas being studied with this new laser.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Optimized precision micromachining using commercially available high-repetition rate microjoule femtosecond fiber lasers

Fiber lasers offer an excellent technology base for production of an industrial-quality tool for ... more Fiber lasers offer an excellent technology base for production of an industrial-quality tool for precision microfabrication, answering the need to expand the capabilities of laser material processing beyond traditional welding, cutting, and other industrial processes. IMRA's FCPA μJewel TM femtosecond fiber laser has been developed to address the particular need for direct-write lasers for creation of clean and high-quality micron and sub-micron features in materials of commercial interest. This flexible Yb:fiber chirped-pulse amplification architecture, capable of operating at rep-rates between 100 kHz and 5 MHz, balances the need for higher-repetition rate with that of sufficient pulse energy to work at or near ablation threshold, while meeting industrial standards for temperature, shock and vibration. Demonstration of the need for higher-repetition rates for direct write processes will be provided in this paper. Further, results of laser-processing of materials typically used in flat panel displays, photomasks, and waveguide production using the FCPA μJewel TM laser will be presented.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A spectroscopic comparison of femtosecond-laser-modified fused silica using kilohertz and megahertz laser systems

Journal of Applied Physics, 2006

Waveguides were written in fused silica using both a femtosecond fiber laser with a 1 MHz pulse r... more Waveguides were written in fused silica using both a femtosecond fiber laser with a 1 MHz pulse repetition rate and a femtosecond amplified Ti:sapphire laser with a 1 kHz repetition rate. Confocal Raman and fluorescence microscopies were used to study structural changes in the waveguides written with both systems. A broad fluorescence band, centered at 650 nm, associated with nonbridging oxygen hole center (NBOHC) defects was observed after waveguide fabrication with the megahertz laser. With the kilohertz laser system these defects were only observed for pulse energies above 1 μJ. Far fewer NBOHC defects were formed with the megahertz laser than with kilohertz writing, possibly due to thermal annealing driven by heat accumulation effects at 1 MHz. When the kilohertz laser was used with pulse energies below 1 μJ, the predominant fluorescence was centered at 550 nm, a band assigned to the presence of silicon clusters (Eδ'). We also observed an increase in the intensity of the 605 cm-1 Raman peak relative to the total Raman intensity, corresponding to an increase in the concentration of three-membered rings in the lines fabricated with both laser systems.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Temporal pulse shaping using fiber laser technology: nano-scaling for flexible industrial laser material processing

On the basis of highly efficient Yb:fiber amplifiers, a new technology platform for compact and n... more On the basis of highly efficient Yb:fiber amplifiers, a new technology platform for compact and nearly maintenance-free laser sources from the femtosecond to the nanosecond time scale has been developed, allowing their application-customized use in industrial laser material processing. The core of this technology is the patented use of multimode fibers with TEM00 output characteristics, enabling high and efficient amplification while maintaining high quality of the output beam. First, we review the fiber laser amplifier developments in the femtosecond pulse regime. Then, we present for the first time a picosecond seed source, Yb fiber amplifier laser design. Next, we present a completely new laser seeder/amplifier design, enabling online temporal tuning of laser pulses between 4 and 20 ns without changing pulse energy by utilizing high-speed control circuitry to adjust pulse duration, repetition rate and pulse energy independently. Pulse length can be optimized to process a given dimension of a sample structure that needs to be modified. Pulse shape can be controlled to produce almost rectangular pulses with <1.5 ns rise times. The resultant pulses can be transported by a polarization-maintaining delivery fiber for easy integration and use in material processing applications. Finally, we describe a few examples of micromachining using pulses from this new, flexible, fiber-based nanosecond laser source.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Vehicle lateral control system using laser radar

This paper introduces our recent research on vehicle lateral control, a component of an automated... more This paper introduces our recent research on vehicle lateral control, a component of an automated highway system (AHS). We have developed a laser radar based automatic steering control system to study the performance and feasibility of such a system in an actual highway environment. Our approach does not require significant infrastructure investment because it is based on the retroreflective road markers currently installed on many roads. The system consists of a laser radar sensor, steering actuator, steering controller, and data processing system. The newly developed laser radar system measures not only the range to a target, but also the azimuth angle of the target in the sensor field of view. The azimuth angle measurement, which is essential for the lateral control system, has been implemented without any moving parts in the sensor system. A line scan CCD is used as the azimuth detector while an APD is used for the range measurement. The vehicle control algorithm was studied using computer simulation and a full-scale test vehicle was developed. Some previous related projects are reviewed and our unique sensor concept is described. The total system performance was demonstrated and evaluated on a California highway. Several issues remaining for further improvement of the system are also discussed.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Experimental Automatic Lateral Control System For An Automobile

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Three-dimensional micromachining inside transparent materials using femtosecond laser pulses: New applications

Page 1. 1 Three-Dimensional Micromachining Inside Transparent Materials Using Femtosecond Laser P... more Page 1. 1 Three-Dimensional Micromachining Inside Transparent Materials Using Femtosecond Laser Pulses: New Applications Jim Bovatseka, Alan Araia, and Chris B. Schafferb aIMRA America, Inc., Applications Research ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Self-assembled periodic sub-wavelength structures by femtosecond laser direct writing

Optics Express, 2006

Self-assembled, sub-wavelength periodic structures are induced in fused silica by a tightly focus... more Self-assembled, sub-wavelength periodic structures are induced in fused silica by a tightly focused, linearly polarized, femtosecond laser beam. Two different types of periodic structures, the main one with period (Lambda(E)) in the direction of the laser beam polarization and the second with period (Lambda(k)) in the direction of the light propagation, are identified from the cross-sectional images of the modified regions using scanning electron microscopy. We demonstrate the spatial coherence of these nanogratings in the plane perpendicular to the beam propagation direction. The range of effective pulse energy which could produce nanogratings narrows when the pulse repetition rate of writing laser increases. The period Lambda(E) is proportional to the wavelength of the writing laser and period Lambda(k) in the head of the modified region remains approximately the wavelength of light in fused silica.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Quill'' writing with ultrashort light pulses in transparent materials

Applied Physics Letters, 2007

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Experimental Results Of Fuzzy Logic Control For Lateral Vehicle Guidance

Bookmarks Related papers MentionsView impact

Research paper thumbnail of <title>Thermal heating effects in writing optical waveguides with 0.1 - 5 MHz repetition rate</title>

Photon Processing in Microelectronics and Photonics IV, 2005

Bookmarks Related papers MentionsView impact

Research paper thumbnail of <title>Ultrashort pulse micromachining with the 10-μJ FCPA fiber laser</title>

Fiber Lasers III: Technology, Systems, and Applications, 2006

IMRA's ultrashort pulse fiber laser products continue to evolve to expand the application sco... more IMRA's ultrashort pulse fiber laser products continue to evolve to expand the application scope. The latest prototype FCPA produces pulses with less than 500-fs pulse duration at a 50-kHz repetition rate. At the fundamental wavelength of 1045 nm, the pulse energy is greater than 10 mJ. The increase in pulse energy over the standard FCPA muJewel permits greater flexibility in

Bookmarks Related papers MentionsView impact

Research paper thumbnail of <title>MHz-rate ultrafast fiber laser for writing of optical waveguides in silica glasses</title>

Commercial and Biomedical Applications of Ultrafast Lasers V, 2005

Direct waveguide writing with femtosecond lasers can be divided into two general categories based... more Direct waveguide writing with femtosecond lasers can be divided into two general categories based upon the type of lasers used: amplified systems that emit high pulse energy (>2 μJ) at low repetition rates (<250 kHz), and oscillators that produce low energy (<200 nJ) at high ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Femtosecond Fiber Laser Microprocessing of Thin Films and Transparent Materials at High Repetition Rates

Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference and Photonic Applications Systems Technologies, 2006

Bookmarks Related papers MentionsView impact

Research paper thumbnail of <title>Temporal pulse shaping using fiber laser technology: nano-scaling for flexible industrial laser material processing</title>

Third International Symposium on Laser Precision Microfabrication, 2003

On the basis of highly efficient Yb:fiber amplifiers, a new technology platform for compact and n... more On the basis of highly efficient Yb:fiber amplifiers, a new technology platform for compact and nearly maintenance-free laser sources from the femtosecond to the nanosecond time scale has been developed, allowing their application-customized use in industrial laser material processing. The core of this technology is the patented use of multimode fibers with TEM00 output characteristics, enabling high and efficient amplification while maintaining high quality of the output beam. First, we review the fiber laser amplifier developments in the femtosecond pulse regime. Then, we present for the first time a picosecond seed source, Yb fiber amplifier laser design. Next, we present a completely new laser seeder/amplifier design, enabling online temporal tuning of laser pulses between 4 and 20 ns without changing pulse energy by utilizing high-speed control circuitry to adjust pulse duration, repetition rate and pulse energy independently. Pulse length can be optimized to process a given dimension of a sample structure that needs to be modified. Pulse shape can be controlled to produce almost rectangular pulses with <1.5 ns rise times. The resultant pulses can be transported by a polarization-maintaining delivery fiber for easy integration and use in material processing applications. Finally, we describe a few examples of micromachining using pulses from this new, flexible, fiber-based nanosecond laser source.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Automatic Vehicle Steering Using a Fixed Orientation Distance Feedback Sensor

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Automatic Vehicle Steering Using a Fixed Orientation Distance Feedback Sensor

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Automatic Vehicle Steering Using a Fixed Orientation Distance Feedback Sensor

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A Theoretical and Experimental Study on Vehicle Lateral Control

The results of an experimental work on the lateral control of a full-scaled vehicle are reported ... more The results of an experimental work on the lateral control of a full-scaled vehicle are reported in this paper. Two control algorithms were tested, a simple PID controller to serve as the baseline, and an optimal preview controller, which was developed to improve the tracking performance, ride quality and robustness of the system. The theoretical development and the experimental setup are briefly discussed, followed by some experimental results.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Laser ablation threshold and etch rate comparison between the ultrafast Yb fiber-based FCPA laser and a Ti:sapphire laser for various materials

Ti:Sapphire lasers remain the most widely used utlrafast laser. However, precise optical alignmen... more Ti:Sapphire lasers remain the most widely used utlrafast laser. However, precise optical alignment and environmental control are necessary for continuous, long-term stable operatoin of the laser. IMRA's FCPA laser is an air-cooled, Yb fiber-based ultrafast laser designed to operate in an industrial environment and provide a stable, high-quality laser beam. In this work, the micromachining performance of the FCPA laser is directly compared with a conventional Ti:Sapphire regenerative amplifier laser. An experimental study was conducted to determine the ablation threshold and etch rate for a variety of materials (including metals, semiconductors, and dielectrics). The materials chosen for the experiments cover a wide range of optical, mechanical and physical properties. Similar focusing conditions were used for both lasers in order to ensure that any differences in the results are primarily due to the different characteristics of each laser. For materials with a relatively low ablation threshold, the full energy of the Ti:Sapphire laser is not needed. Furthermore, it is near the ablation threshold where ultrafast laser processing provides the benefit of minimal thermal damage to the surrounding material. Although the relatively low pulse energy of the FCPA limits its ability to ablate some harder materials, its high repetition rate increases the material processing speed and its good beam quality and stability facilitates tight, efficient focusing for precise machining of small features.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Ultrashort pulse micromachining with the 10-muJ FCPA fiber laser

IMRA's ultrashort pulse fiber laser products continue to evolve to expand the application scope. ... more IMRA's ultrashort pulse fiber laser products continue to evolve to expand the application scope. The latest prototype FCPA produces pulses with less than 500-fs pulse duration at a 50-kHz repetition rate. At the fundamental wavelength of 1045 nm, the pulse energy is greater than 10 mJ. The increase in pulse energy over the standard FCPA μJewel permits greater flexibility in the focusing conditions applicable for micromachining, enabling a wider variety of laser-machined structures and profiles. This paper describes the latest micromachining application areas being studied with this new laser.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Optimized precision micromachining using commercially available high-repetition rate microjoule femtosecond fiber lasers

Fiber lasers offer an excellent technology base for production of an industrial-quality tool for ... more Fiber lasers offer an excellent technology base for production of an industrial-quality tool for precision microfabrication, answering the need to expand the capabilities of laser material processing beyond traditional welding, cutting, and other industrial processes. IMRA's FCPA μJewel TM femtosecond fiber laser has been developed to address the particular need for direct-write lasers for creation of clean and high-quality micron and sub-micron features in materials of commercial interest. This flexible Yb:fiber chirped-pulse amplification architecture, capable of operating at rep-rates between 100 kHz and 5 MHz, balances the need for higher-repetition rate with that of sufficient pulse energy to work at or near ablation threshold, while meeting industrial standards for temperature, shock and vibration. Demonstration of the need for higher-repetition rates for direct write processes will be provided in this paper. Further, results of laser-processing of materials typically used in flat panel displays, photomasks, and waveguide production using the FCPA μJewel TM laser will be presented.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A spectroscopic comparison of femtosecond-laser-modified fused silica using kilohertz and megahertz laser systems

Journal of Applied Physics, 2006

Waveguides were written in fused silica using both a femtosecond fiber laser with a 1 MHz pulse r... more Waveguides were written in fused silica using both a femtosecond fiber laser with a 1 MHz pulse repetition rate and a femtosecond amplified Ti:sapphire laser with a 1 kHz repetition rate. Confocal Raman and fluorescence microscopies were used to study structural changes in the waveguides written with both systems. A broad fluorescence band, centered at 650 nm, associated with nonbridging oxygen hole center (NBOHC) defects was observed after waveguide fabrication with the megahertz laser. With the kilohertz laser system these defects were only observed for pulse energies above 1 μJ. Far fewer NBOHC defects were formed with the megahertz laser than with kilohertz writing, possibly due to thermal annealing driven by heat accumulation effects at 1 MHz. When the kilohertz laser was used with pulse energies below 1 μJ, the predominant fluorescence was centered at 550 nm, a band assigned to the presence of silicon clusters (Eδ'). We also observed an increase in the intensity of the 605 cm-1 Raman peak relative to the total Raman intensity, corresponding to an increase in the concentration of three-membered rings in the lines fabricated with both laser systems.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Temporal pulse shaping using fiber laser technology: nano-scaling for flexible industrial laser material processing

On the basis of highly efficient Yb:fiber amplifiers, a new technology platform for compact and n... more On the basis of highly efficient Yb:fiber amplifiers, a new technology platform for compact and nearly maintenance-free laser sources from the femtosecond to the nanosecond time scale has been developed, allowing their application-customized use in industrial laser material processing. The core of this technology is the patented use of multimode fibers with TEM00 output characteristics, enabling high and efficient amplification while maintaining high quality of the output beam. First, we review the fiber laser amplifier developments in the femtosecond pulse regime. Then, we present for the first time a picosecond seed source, Yb fiber amplifier laser design. Next, we present a completely new laser seeder/amplifier design, enabling online temporal tuning of laser pulses between 4 and 20 ns without changing pulse energy by utilizing high-speed control circuitry to adjust pulse duration, repetition rate and pulse energy independently. Pulse length can be optimized to process a given dimension of a sample structure that needs to be modified. Pulse shape can be controlled to produce almost rectangular pulses with <1.5 ns rise times. The resultant pulses can be transported by a polarization-maintaining delivery fiber for easy integration and use in material processing applications. Finally, we describe a few examples of micromachining using pulses from this new, flexible, fiber-based nanosecond laser source.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Vehicle lateral control system using laser radar

This paper introduces our recent research on vehicle lateral control, a component of an automated... more This paper introduces our recent research on vehicle lateral control, a component of an automated highway system (AHS). We have developed a laser radar based automatic steering control system to study the performance and feasibility of such a system in an actual highway environment. Our approach does not require significant infrastructure investment because it is based on the retroreflective road markers currently installed on many roads. The system consists of a laser radar sensor, steering actuator, steering controller, and data processing system. The newly developed laser radar system measures not only the range to a target, but also the azimuth angle of the target in the sensor field of view. The azimuth angle measurement, which is essential for the lateral control system, has been implemented without any moving parts in the sensor system. A line scan CCD is used as the azimuth detector while an APD is used for the range measurement. The vehicle control algorithm was studied using computer simulation and a full-scale test vehicle was developed. Some previous related projects are reviewed and our unique sensor concept is described. The total system performance was demonstrated and evaluated on a California highway. Several issues remaining for further improvement of the system are also discussed.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Experimental Automatic Lateral Control System For An Automobile

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Three-dimensional micromachining inside transparent materials using femtosecond laser pulses: New applications

Page 1. 1 Three-Dimensional Micromachining Inside Transparent Materials Using Femtosecond Laser P... more Page 1. 1 Three-Dimensional Micromachining Inside Transparent Materials Using Femtosecond Laser Pulses: New Applications Jim Bovatseka, Alan Araia, and Chris B. Schafferb aIMRA America, Inc., Applications Research ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Self-assembled periodic sub-wavelength structures by femtosecond laser direct writing

Optics Express, 2006

Self-assembled, sub-wavelength periodic structures are induced in fused silica by a tightly focus... more Self-assembled, sub-wavelength periodic structures are induced in fused silica by a tightly focused, linearly polarized, femtosecond laser beam. Two different types of periodic structures, the main one with period (Lambda(E)) in the direction of the laser beam polarization and the second with period (Lambda(k)) in the direction of the light propagation, are identified from the cross-sectional images of the modified regions using scanning electron microscopy. We demonstrate the spatial coherence of these nanogratings in the plane perpendicular to the beam propagation direction. The range of effective pulse energy which could produce nanogratings narrows when the pulse repetition rate of writing laser increases. The period Lambda(E) is proportional to the wavelength of the writing laser and period Lambda(k) in the head of the modified region remains approximately the wavelength of light in fused silica.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Quill'' writing with ultrashort light pulses in transparent materials

Applied Physics Letters, 2007

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Experimental Results Of Fuzzy Logic Control For Lateral Vehicle Guidance

Bookmarks Related papers MentionsView impact

Research paper thumbnail of <title>Thermal heating effects in writing optical waveguides with 0.1 - 5 MHz repetition rate</title>

Photon Processing in Microelectronics and Photonics IV, 2005

Bookmarks Related papers MentionsView impact

Research paper thumbnail of <title>Ultrashort pulse micromachining with the 10-μJ FCPA fiber laser</title>

Fiber Lasers III: Technology, Systems, and Applications, 2006

IMRA's ultrashort pulse fiber laser products continue to evolve to expand the application sco... more IMRA's ultrashort pulse fiber laser products continue to evolve to expand the application scope. The latest prototype FCPA produces pulses with less than 500-fs pulse duration at a 50-kHz repetition rate. At the fundamental wavelength of 1045 nm, the pulse energy is greater than 10 mJ. The increase in pulse energy over the standard FCPA muJewel permits greater flexibility in

Bookmarks Related papers MentionsView impact

Research paper thumbnail of <title>MHz-rate ultrafast fiber laser for writing of optical waveguides in silica glasses</title>

Commercial and Biomedical Applications of Ultrafast Lasers V, 2005

Direct waveguide writing with femtosecond lasers can be divided into two general categories based... more Direct waveguide writing with femtosecond lasers can be divided into two general categories based upon the type of lasers used: amplified systems that emit high pulse energy (>2 μJ) at low repetition rates (<250 kHz), and oscillators that produce low energy (<200 nJ) at high ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Femtosecond Fiber Laser Microprocessing of Thin Films and Transparent Materials at High Repetition Rates

Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference and Photonic Applications Systems Technologies, 2006

Bookmarks Related papers MentionsView impact

Research paper thumbnail of <title>Temporal pulse shaping using fiber laser technology: nano-scaling for flexible industrial laser material processing</title>

Third International Symposium on Laser Precision Microfabrication, 2003

On the basis of highly efficient Yb:fiber amplifiers, a new technology platform for compact and n... more On the basis of highly efficient Yb:fiber amplifiers, a new technology platform for compact and nearly maintenance-free laser sources from the femtosecond to the nanosecond time scale has been developed, allowing their application-customized use in industrial laser material processing. The core of this technology is the patented use of multimode fibers with TEM00 output characteristics, enabling high and efficient amplification while maintaining high quality of the output beam. First, we review the fiber laser amplifier developments in the femtosecond pulse regime. Then, we present for the first time a picosecond seed source, Yb fiber amplifier laser design. Next, we present a completely new laser seeder/amplifier design, enabling online temporal tuning of laser pulses between 4 and 20 ns without changing pulse energy by utilizing high-speed control circuitry to adjust pulse duration, repetition rate and pulse energy independently. Pulse length can be optimized to process a given dimension of a sample structure that needs to be modified. Pulse shape can be controlled to produce almost rectangular pulses with <1.5 ns rise times. The resultant pulses can be transported by a polarization-maintaining delivery fiber for easy integration and use in material processing applications. Finally, we describe a few examples of micromachining using pulses from this new, flexible, fiber-based nanosecond laser source.

Bookmarks Related papers MentionsView impact