Vertical-external-cavity surface-emitting lasers (VECSELs) are the most versatile laser sources, combining unique features such as wide spectral coverage, ultrashort pulse operation, low noise properties, high output power, high brightness and compact form-factor. This paper reviews the recent technological developments of VECSELs in connection with the new milestones that continue to pave the way towards their use in numerous applications. Significant attention is devoted to the fabrication of VECSEL gain mirrors in challenging wavelength regions, especially at the yellow and red wavelengths. The reviewed fabrication approaches address wafer-bonded VECSEL structures as well as the use of hybrid mirror structures. Moreover, a comprehensive summary of VECSEL characterization methods is presented; the discussion covers different stages of VECSEL development and different operation regimes, pointing out specific characterization techniques for each of them. Finally, several emerging applications are discussed, with emphasis on the unique application objectives that VECSELs render possible, for example in atom and molecular physics, dermatology and spectroscopy.

https://iopscience.iop.org/article/10.1088/1361-6463/aa7bfd/pdf

Optically pumped VECSELs: review of technology and progress

We report a first dissipative dispersive-managed soliton fiber laser operating at 2 μm The cavity comprised of all-anomalous-dispersion fiber employs chirped fiber Bragg grating, which ensures net-normal cavity dispersion and semiconductor saturable absorber for mode-locking

Dissipative dispersion-managed soliton 2 μm thulium/holmium fiber laser

The report on a study of laser emission from a conceptually new organic material based on transparent wood (TW) with embedded dye Rhodamine 6G molecules is presented in this paper. The lasing perfo ...

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/adom.201700057

Lasing from Organic Dye Molecules Embedded in Transparent Wood

Conference on Lasers and Electro-Optics, 2008 and 2008 Conference on Quantum Electronics and Laser Science. CLEO/QELS 2008

We demonstrate passive mode-locking of a Raman fiber laser using a nanotube-based saturable absorber coupled to a net normal dispersion cavity. This generates highly chirped 500 ps pulses. These are then compressed down to 2 ps, with 1.4 kW peak power, making it a simple wavelength-versatile source for various applications.

/pdf/ultrafast-raman-laser-mode-locked-by-nanotubes-xbi9gfcd3l.pdf

Ultrafast Raman laser mode-locked by nanotubes.

3 W at genuine red wavelength of 650 nm has been achieved from a semiconductor disk laser by frequency doubling. An InP based active medium was fused with a GaAs/AlGaAs distributed Bragg reflector resulting in an integrated monolithic gain mirror. 6.6 W of output power at the fundamental wavelength of 1.3 µm represents the best achievement reported to date for this type of lasers.

3 W of 650 nm red emission by frequency doubling of wafer-fused semiconductor disk laser.

A mode-locked Raman fiber laser pumped by 1.3 µm semiconductor disk laser is demonstrated. Direct Watt-level core-pumping of the single-mode fiber Raman lasers and amplifiers with low-noise disk lasers is demonstrated to represent a highly practical solution as compared with conventional scheme using pumping by Raman wavelength convertors. Raman laser employing passive mode-locking by nonlinear polarization evolution in normal dispersion regime produces stable pedestal-free 1.97 ps pulses at 1.38 µm. Using semiconductor disk lasers capable of producing high power with diffraction-limited beam allows Raman gain to be obtained at virtually any wavelength of interest owing to spectral versatility of semiconductor gain materials and wafer-fusing technology.

1.38-µm mode-locked Raman fiber laser pumped by semiconductor disk laser

We demonstrate an optically pumped semiconductor disk laser operating at 1580 nm with 4.6 W of output power, which represents the highest output power reported from this type of laser. 1 W of output power at 785 nm with nearly diffraction-limited beam has been achieved from this laser through intracavity frequency doubling, which offers an attractive alternative to Ti:sapphire lasers and laser diodes in a number of applications, e.g., in spectroscopy, atomic cooling and biophotonics.

1 W at 785 nm from a frequency-doubled wafer-fused semiconductor disk laser.

We present a gold-to-gold bonding method that combines features of surface activated bonding and capillary bonding. The process is performed at a relatively low temperature of 150°C and therefore allows the integration of materials with highly mismatched coefficients of thermal expansion. In this letter, the potential of this technique is illustrated by assembling a high-power flip chip semiconductor disk laser utilizing a chemical vapor deposition diamond heat spreader. The laser produces up to 14 W of output power at 15°C gain element temperature with a nearly diffraction-limited output beam. Further scaling of bonding area to wafer-level could make this method useful in the packaging of various optoelectronic and microelectronic components.

Antti Rantamäki

Papers

Optically pumped VECSELs: review of technology and progress

3 W of 650 nm red emission by frequency doubling of wafer-fused semiconductor disk laser.

1.38-µm mode-locked Raman fiber laser pumped by semiconductor disk laser

1 W at 785 nm from a frequency-doubled wafer-fused semiconductor disk laser.

Low Temperature Gold-to-Gold Bonded Semiconductor Disk Laser