100-W+ diode laser bars show &gt; 71% power conversion from 790- nm to 1000-nm and have clear route to &gt; 85%

Crump, P.; Dong, Weimin; Grimshaw, Mike; Wang, Jun; Patterson, Steve; Wise, Damian; DeFranza, Mark; Elim, Sandrio; Zhang, Shiguo; Bougher, Mike; Patterson, Jason; Das, Samaresh; Bell, Jake; Farmer, Jason; DeVito, Mark; Martinsen, R.

doi:10.1117/12.704496

Cited by 46 publications

(17 citation statements)

References 7 publications

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“…E/O efficiencies >39% have already been demonstrated by multi-kW spectrally beam combined fiber-coupled diode lasers (Honea et al, 2013). Focused development under the DARPA SHEDs program has also lead to extremely high power conversion efficiency in the 9xx-nm wavelength band, leading to diode bars with efficiency in excess of 74% and a clear route to efficiencies superior to 85% at room temperature (Crump et al, 2007). With demonstrated slope efficiency of optical fibers on the order of 80% (Jeong et al, 2004) and a demonstrated efficiency of spectral beam combining techniques of 91% (Drachenberg et al, 2011), we consider in this paper a global E/O efficiency of 50%.…”

Section: Laser Ablationmentioning

confidence: 98%

Statistical multi-criteria evaluation of non-nuclear asteroid deflection methods

Thiry

Vasile

2017

Acta Astronautica

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This version is available at https://strathprints.strath.ac.uk/61691/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the AbstractIn this paper we assess and compare the effectiveness of four classes of nonnuclear asteroid deflection methods applied to a wide range of virtual collision scenarios. We consider the kinetic impactor, laser ablation, the ion beaming technique and two variants of the gravity tractor. A simple but realistic model of each deflection method was integrated within a systematic approach to size the spacecraft and predict the achievable deflection for a given mission and a given maximum mass at launch. A sample of 100 synthetic asteroids was then created from the current distribution of NEAs and global optimisation methods were used to identify the optimal solution in each case according to two criteria: the minimum duration between the departure date and the time of virtual impact required to deflect the NEA by more than two Earth radii and the maximum miss-distance achieved within a total duration of 10 years. Our results provide an interesting insight into the range of applicability of individual deflection methods and argue the need to develop multiple methods in parallel for a global mitigation of all possible threats.

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Section: Laser Ablationmentioning

confidence: 98%

Statistical multi-criteria evaluation of non-nuclear asteroid deflection methods

Thiry

Vasile

2017

Acta Astronautica

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“…These types of conductive coolers are capable of linear output power operation at low input currents but are insufficient at preventing thermal roll-over and sustained peak wall-plug efficiency at higher input currents. The impact of a cooler's thermal resistance on lasing performance can be calculated using a temperature dependent model for output power shown in (1) where (2) is the slope efficiency and (3) the threshold current. ,…”

Section: Copper Coolersmentioning

confidence: 99%

“…The adoption of Molecular Beam Epitaxy (MBE) and Metal-Organic Chemical Vapor Deposition (MOCVD) increased the growth precision down to <1 nm which led to dramatic decreases in internal loss down to ~0.35 cm -1 [2]. Moreover, improvements in material growth and laser epitaxial design from efforts such as the DARPA SHEDS program, has demonstrated laser diode efficiencies as high as 85% [1]. This has enabled the growth of laser cavities as long as 8mm in length [3] which has greatly reduced the thermal resistance of laser diode bars and has allowed for the development of higher power lasers diodes.…”

Section: Introductionmentioning

confidence: 98%

Numerical modeling and simulation of laser diode diamond microcoolers

Matin

Zheng

Bar‐Cohen

2014

Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)

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High heat flux management schemes in laser diodes require appropriate cooling applications. Micro channel coolers are now widely used in high power laser diode industry with the highest total thermal resistance reported as low as 0.03 cm 2 -K/W with pressure drops as low as 10~50 psi. Since, the geometries, flow rates as well as high heat fluxes of current SOA LD micro-coolers differ, it is necessary to understand their thermal performance relative to conductive, convective and caloric thermal resistance. To do this comparison an equivalent effective micro-cooler thermal model is developed and then iterated with scaled input parameters from SOA LD micro-coolers. The objective is to identify the dominant thermal resistance -that plays the major role in decreasing the total thermal resistance. This paper will then predict a micro cooler that will perhaps be able to reduce total thermal resistance lower than 0.01 Kcm 2 /W with minimal pressure drop for next generation high heat flux applications. The current study will be restricted to only single phase liquid cooling.

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“…High-power narrow-vertical-divergence photonic band crystal laser diodes with optimized epitaxial structure Lei Liu,1,2 Hongwei Qu, 1,2 Yun Liu, 1,2 Yejin Zhang, 1,2 Yufei Wang, 2 Aiyi Qi, 2 and Wanhua Zheng 1,2,a) 900 nm longitudinal photonic band crystal (PBC) laser diodes with optimized epitaxial structure are fabricated. With a same calculated fundamental-mode divergence, stronger mode discrimination is achieved by a quasi-periodic index modulation in the PBC waveguide than a periodic one.…”

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confidence: 99%

High-power narrow-vertical-divergence photonic band crystal laser diodes with optimized epitaxial structure

Liu

et al. 2014

Applied Physics Letters

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100-W+ diode laser bars show > 71% power conversion from 790- nm to 1000-nm and have clear route to > 85%

Cited by 46 publications

References 7 publications

Statistical multi-criteria evaluation of non-nuclear asteroid deflection methods

Statistical multi-criteria evaluation of non-nuclear asteroid deflection methods

Numerical modeling and simulation of laser diode diamond microcoolers

High-power narrow-vertical-divergence photonic band crystal laser diodes with optimized epitaxial structure

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