Browsing by Author "Kuo, Shuo-Yi"

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Demonstration of polarization control GaN-based micro-cavity lasers using a rigid high-contrast grating reflector
(2019-09-10)
Chang, Tsu-Chi
;
Kuo-Bin Hong
;
Kuo, Shuo-Yi
;
Lu, Tien-Chang
;
光電工程學系
We reported on GaN microcavity (MC) lasers combined with one rigid TiO2 high-contrast grating (HCG) structure as the output mirror. The HCG structure was directly fabricated on the GaN structure without an airgap. The entire MC structure comprised a bottom dielectric distributed Bragg reflector; a GaN cavity; and a top HCG reflector, which was designed to yield high reflectance for transverse magnetic (TM)- or transverse electric (TE)-polarized light. The MC device revealed an operation threshold of approximately 0.79 MW/cm(2) when pulsed optical pumping was conducted using the HCG structure at room temperature. The laser emission was TM polarized with a degree of polarization of 99.2% and had a small divergence angle of 14 degrees (full width at half maximum). This laser operation demonstration for the GaN-based MC structure employing an HCG exhibited the advantages of HCGs in semiconductor lasers at wavelengths from green to ultraviolet.
GaN vertical-cavity surface-emitting laser with a high-contrast grating reflector
(2018-01-01)
Chang, Tsu-Chi
;
Kuo, Shuo-Yi
;
Hashemi, Ehsan
;
Haglund, Asa
;
Lu, Tien-Chang
We report a GaN-based VCSEL with a high-contrast grating (HCG) as the top mirror. The HCG consisted of TiO2 and rested directly on the n-GaN without an airgap or the use of any DBR layers to boost the reflectivity. The full VCSEL structure was optically pumped at room temperature and showed a lasing threshold of approximately 0.69MW/cm(2) and a lasing wavelength at 369.1 nm. This first demonstration of lasing in a HCG GaN based VCSEL opens up the possibility to explore all the potential benefits of HCGs in the blue and ultraviolet spectral regime.
Lasing action in GaN-based VCSELs with top high-contrast grating reflectors
(2018-01-01)
Chang, Tsu-Chi
;
Kuo, Shuo-Yi
;
Hashemi, Ehsan
;
Haglund, Asa
;
Lu, Tien-Chang
We report a GaN-based VCSEL with a high-contrast grating (HCG) as the top mirror. The HCG consisted of TiO2 and rested directly on the n-GaN without an airgap or the use of any DBR layers to boost the reflectivity. The full VCSEL structure was optically pumped at room temperature and showed a lasing threshold of approximately 0.99 MW/cm(2) and a lasing wavelength at 369.8 nm. The demonstration of HCG GaN-based VCSEL opens up the possibility to explore all the potential benefits of HCGs in the blue and ultraviolet spectral regime.