RefleKron Revolutionizes Laser Industry with Cutting-Edge SESAM Technology

Posted  by GoPhotonics


RefleKron, a leading provider of customized semiconductor saturable absorber mirrors (SESAMs), distinguishes itself through its unparalleled expertise in semiconductor technology, in-house epitaxy, SESAM design, and laser physics. With a commitment to innovation and excellence, RefleKron delivers bespoke SESAM solutions for mode-locking and Q-switching applications, spanning a broad wavelength range from 0.6 µm to 3 µm. This dedication positions RefleKron at the forefront of the laser industry, driving advancements that revolutionize various sectors.

The company originates from the Optoelectronics Research Centre at Tampere University of Technology. Established in 2004, at the rise of the ultrafast fiber laser industry, RefleKron has gained recognition for scientific and industrial development of SESAMs for a large variety of ultrafast and Q-switched lasers. As the industrial leader in customized SESAMs, RefleKron actively advances SESAM technology beyond its current limits to explore new lasers and wavelengths.

Customized SESAM Technology

Customized SESAMs are instrumental in the development and volume production of pulsed laser systems including fiber lasers, solid-state lasers, and semiconductor lasers operating in both mode-locked and Q-switched regimes. A team of experts proficient in semiconductor technology and laser physics stands ready to offer comprehensive consulting tailored to individual applications, ensuring the provision of customized SESAMs optimized for superior performance, prolonged lifespan, and consistent repeatability in volume production.

The design of their SESAMs relies on monolithic semiconductor structures fabricated through Molecular Beam Epitaxy (MBE), utilizing versatile material systems such as GaAs, InP, and GaSb. The inherent flexibility of this material system allows for the engineering of semiconductor mirrors across a wide wavelength spectrum, ranging from 620 nm to 3.5 µm.

Significance of Customized SESAMs

In laser technology, a prevailing misconception surrounding semiconductor saturable absorber mirrors (SESAMs) suggests they suffer from unreliability, poor lifetimes, and inconsistent repeatability. However, RefleKron, a leading authority in SESAM development, dispels these notions, emphasizing that such drawbacks only arise when SESAMs operate beyond their optimal parameters. RefleKron's experts explain that if SESAMs are not adequately tailored to a laser's architecture, excessive fluences may be required to stave off Q-switching, leading to subpar performance. By crafting SESAMs tailored to each laser's specific needs, RefleKron ensures operation within an optimal working regime, thereby prolonging SESAM lifetimes significantly—a critical factor for industrial applications. 

The company's deep understanding of process optimization and extensive experience in Molecular Beam Epitaxy (MBE) technology further bolster its capabilities. This expertise enables RefleKron to achieve remarkable wafer-to-wafer repeatability, a crucial aspect of industrial-scale production. Notably, SESAM product lines repeatedly undergo stringent testing, consistently exceeding 10,000 hours of operational lifespan and demonstrating superior repeatability across wafers.

The flexibility in material selection offers additional benefits to both the absorber layer and cavity design. Consequently, the nonlinearity and saturation properties of the SESAM can be precisely customized for specific laser systems, irrespective of the wavelength range. This enables adjustments in nonlinear absorption from below 0.5% to over 90%, with saturation fluences spanning from 10 µJ/cm² to above 100 µJ/cm².

The relaxation time stands out as a crucial parameter for SESAM repeatability, particularly pivotal in volume production settings. RefleKron boasts extensive expertise in manipulating absorber defect density to exert precise control over SESAM absorption recovery dynamics. This proficiency allows for the customization of relaxation times ranging from sub-picoseconds to nanoseconds, perfectly aligning with the requirements of each specific application. Notably, a notable instance arises with GaSb-based SESAMs operating at wavelengths of 2 µm and beyond, characterized by rapid recombination dynamics featuring a sub-picosecond relaxation time component.

RefleKron stands at the forefront of SESAM development, offering tailored solutions for mode-locking and Q-switching applications across a wide wavelength spectrum. Their expertise in semiconductor technology, epitaxy, and laser physics ensures the provision of SESAMs optimized for superior performance and repeatability in volume production. By addressing misconceptions and customizing SESAMs to match specific laser architectures, RefleKron continues to lead the way in advancing SESAM technology, paving the path for groundbreaking innovations in the field of laser systems.

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