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Contract Opportunity

Opportunity:

Lawrence Livermore National Laboratory (LLNL), operated by the Lawrence Livermore National Security (LLNS), LLC under contract no. DE-AC52-07NA27344 (Contract 44) with the U.S. Department of Energy (DOE), is offering the opportunity to enter into a collaboration to further develop and commercialize its method of reducing detrimental thermal lensing effects on laser diode beam quality.

Background:

Maximizing the brightness of semiconductor laser diodes is important for increasing the delivery of their optical output to gain media, in order to enhance the output power and efficiency of diode pumped lasers. Devices such as fiber lasers, diode-pumped solid-state lasers, and diode-pumped gas lasers all benefit from improved laser diode brightness. A particular challenge for laser diodes is a significant increase in their slow-axis divergence when operated at high power output. The increased divergence results in a (proportional) decrease in diode brightness. It is believed to be caused by thermal lensing, which in turn is induced by waste heat in the semiconductor laser that spreads along the slow axis to create a thermal profile. The change in semiconductor temperature causes a change in refractive index which forms a thermal lens.

Description:

Laser diode lensing effect can be substantially reduced by creating a pattern interface such that the substrate is only attached at the diode mesa. This is achieved by either creating a pattern solder joint and/or pattern substrate.

In a standard diode attach process, planar substrate surface is attached to the laser diode for heatsinking purpose. However, for high power diode with large emitter array, this can cause a thermal lensing issue due to large temperature difference within each emitter. Changing emitter pitch and or changing emitter width have minimal effect on thermal lensing problem for the planar interface.

This effect can be substantially reduced by creating a pattern interface such that the substrate is only attached at the diode mesa. This is achieved by either creating a pattern solder joint and/or pattern substrate.

Advantages/Benefits:

• Minimizes detrimental thermal lensing effects.


• Limits slow axis divergence in laser diodes at high output power levels.


• Improves overall laser diode brightness at high output power levels.

Potential Applications:

• High average power laser materials processing


• High average power solid-state laser and fiber laser pumping

Development Status:

Current stage of technology development: TRL 2-3

LLNL has filed for patent protection on this invention.

U.S. Patent Application No. 2023/0106189 Patterning of Diode/Substrate Interface to Reduce Thermal Lensing published 4/6/2023

LLNL is seeking industry partners with a demonstrated ability to bring such inventions to the market. Moving critical technology beyond the Laboratory to the commercial world helps our licensees gain a competitive edge in the marketplace. All licensing activities are conducted under policies relating to the strict nondisclosure of company proprietary information.

Please visit the IPO website at https://ipo.llnl.gov/resources for more information on working with LLNL and the industrial partnering and technology transfer process.

Note: THIS IS NOT A PROCUREMENT. Companies interested in commercializing LLNL's method of reducing detrimental thermal lensing effects on laser diode beam quality should provide an electronic OR written statement of interest, which includes the following:

1. Company Name and address.


2. The name, address, and telephone number of a point of contact.


3. A description of corporate expertise and/or facilities relevant to commercializing this technology.

Please provide a complete electronic OR written statement to ensure consideration of your interest in LLNL's method of reducing detrimental thermal lensing effects on laser diode beam quality.

The subject heading in an email response should include the Notice ID and/or the title of LLNL’s Technology/Business Opportunity and directed to the Primary and Secondary Point of Contacts listed below.

Written responses should be directed to:

Lawrence Livermore National Laboratory

Innovation and Partnerships Office

P.O. Box 808, L-779

Livermore, CA 94551-0808

Attention: IL-13498

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