Despeckling fly’s eye homogenizer for single mode laser diodes

Mizuyama, Yosuke; Harrison, Nathan; Leto, Riccardo

doi:10.1364/oe.21.009081

Cited by 5 publications

(3 citation statements)

References 7 publications

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“…When directly using laser beams as the light source in headlamp systems, a further investigation of whether the laser speckle impacts the illumination performance should be made. When necessary, additional optics or vibrators can be considered as complementary elements to the LAs to cope with the speckle pattern [26,27]. Besides the laser speckle, the projection homogeneity is affected by the aperture ratio of the LCoS as well.…”

Section: Prototype Demonstrationmentioning

confidence: 99%

Beam Pre-Shaping Methods Using Lenslet Arrays for Area-Based High-Resolution Vehicle Headlamp Systems

Knöchelmann

Lachmayer

2020

Applied Sciences

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High-resolution light distributions are lately in demand for vehicle headlamp systems as an innovative lighting approach. This lighting approach can realize functionalities, such as precise glare avoidance and on-road projection, which are useful for improving traffic comfort and safety. For achieving the required high-resolution light distribution, area-based projection technologies, such as DMD, LCD, and LCoS, are considered to be integrated into such headlamps. These projection devices demand rectangular illumination areas with specific light distributions to fulfill the requirements for illumination efficiency and performance in headlamp systems. Lenslet arrays, based on the principle of Köhler illumination, can effectively homogenize the light and shape it into rectangular shapes simultaneously. Such components are widely used in projection applications. However, they also show functional potentialities to be applied in high-resolution headlamps. This paper explains the design principles and methods of lenslet arrays for beam pre-shaping in headlamp systems. It validates the homogenization using a self-designed and manufactured lenslet array in a demonstrator in the first place. Afterward, this paper introduces two new methods for the centralized beam shaping required by some headlamps. These methods are validated by optical simulations.

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Section: Prototype Demonstrationmentioning

confidence: 99%

Beam Pre-Shaping Methods Using Lenslet Arrays for Area-Based High-Resolution Vehicle Headlamp Systems

Knöchelmann

Lachmayer

2020

Applied Sciences

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“…An ever-present consequence of using highly coherent illumination is speckle, arising from selfinterference of the beam as it propagates through the optical system. While some have harnessed this effect for beneficial results [60,61], it is more often undesirable and needs to be reduced or suppressed [62,63]. This random intensity variation is particularly problematic for lithography, since it creates spatial noise in the reconstructed intensity pattern.…”

Section: Speckle Reductionmentioning

confidence: 99%

Volumetric Additive Manufacturing of Polymer Structures by Holographically Projected Light Fields

Shusteff

2017

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The experience of completing this doctoral dissertation has been akin to the effort of climbing a tall mountain peakreaching the top, you look around with satisfaction and a sense of accomplishment (and possibly also fatigue), and see all the others who made the climb with you. Just as the tallest peaks are virtually impossible to climb without a team, this PhD is not something that I did alone, and the accomplishment belongs as much to my family, friends, and colleagues as it does to me. Most prominently, I owe an enormous debt of gratitude to my wife Tamar. Thank you for supporting and encouraging this slightly foolish endeavor of a PhD all the way through, in the myriad ways that you did (and the ways I didn't even notice), though I was already prone to bouts of working a little too hard even before I started. Мама и папа, вам я вечно благодарен за прочное основание знаний и любви к учёбe. Вы научили меня что такое старание до последних усилий, и зародили во мне безграничноe любопытство, без которых никакой исследователь из меня не мог бы выйтидоктор или нет. И конечно за тот месяц, что вы провели у нас, позволив мне сделать последний рывок к финишу. To my brother Sasha, thank you for putting me up for every visit to Boston to meet with my committee, and for always keeping me humble. To my kids, thank you for being a constant reminder that life is more than work; I hope one day this thesis might serve as a measure of inspiration to climb your own mountain. Thank you to all the friends who cheered, needled, heckled, commiserated, and cheered again along the way, especially Jessica Blazer, and Dr. Dave Sopchak. In the professional realm, thank you foremost to Chris Spadaccini, my friend and unfailingly supportive center lead, for the trust you place in those who work for you, and the example you set as a leader. To my thesis supervisor Prof. Nick Fang, our longtime collaborator, for being willing to take on a grad student with a very weird arrangement, and to my other committee members Profs. Karl Berggren and Jeff Lang for your guidance and mentorship throughout. To the staff of the MIT EECS Graduate Office, who enabled me to thread the administrative and bureaucratic needles needed to get to this point. The reason I could carry out this research at all is because I'm highly fortunate to work with the additive manufacturing team at LLNL, a truly exceptional group of people. When talking about my job, I always tell people how lucky I am to be able to learn something literally every single day; my generous, creative, and knowledgeable colleagues are the reason why. Thanks especially to Allie Browar for the Kingdom of Cubes, and to James Oakdale and Todd Weisgraber for giving me a framework which allowed me to start filling in the yawning gaps in my understanding of photopolymerization. Thank you to my other colleagues, who are too many to nameyour kindness and advice, technical and otherwise, and good humor most of all give me the real reasons that I like coming in to work every day. To those of my managers who s...

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“…In one dimension, the lenticular array converts the plane wave into a series of cylindrically expanding wave fronts thus reducing the spatial coherence of the wavefront. This element alone serves to partially reduce the speckle seen in the visible line but the temporal coherence also plays a role [5]. This is the first step to reducing the speckle of a laser-line scanning system while maintaining the minimum focus size for higher spatial resolution.…”

Section: -D Beam Homogenizersmentioning

confidence: 99%

Laser-line scanning speckle reduction based on a one-dimensional beam homogenizer

Nelsen

Hartmann

2017

SPIE Proceedings

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Despeckling fly’s eye homogenizer for single mode laser diodes

Cited by 5 publications

References 7 publications

Beam Pre-Shaping Methods Using Lenslet Arrays for Area-Based High-Resolution Vehicle Headlamp Systems

Beam Pre-Shaping Methods Using Lenslet Arrays for Area-Based High-Resolution Vehicle Headlamp Systems

Volumetric Additive Manufacturing of Polymer Structures by Holographically Projected Light Fields

Laser-line scanning speckle reduction based on a one-dimensional beam homogenizer

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