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Quantum dot vertical-cavity surface-emitting lasers covering the 'green gap'.
Yang Mei1, Guo-En Weng1,2, Bao-Ping Zhang1
1Department of Electronic Engineering, Optoelectronics Engineering Research Center, Xiamen University, Xiamen, Fujian 361005, China.
Light, Science & Applications
|September 1, 2018
Summary
Researchers developed green vertical-cavity surface-emitting lasers (VCSELs) using quantum dots. These lasers achieve record low thresholds, long wavelengths, and continuous-wave operation, crucial for advanced displays.
Area of Science:
- Optoelectronics
- Semiconductor Lasers
Background:
- The 'green gap' in semiconductor lasers remains a challenge for full-color displays.
- Existing green laser technologies often face limitations in efficiency and performance.
Purpose of the Study:
- To demonstrate semiconductor vertical-cavity surface-emitting lasers (VCSELs) operating across the green spectrum.
- To achieve record-breaking performance metrics for green VCSELs, including low threshold current and continuous-wave operation.
Main Methods:
- Utilized a consistent quantum dot (QD) active region for all demonstrated lasers.
- Controlled emission wavelength by precisely adjusting the cavity length.
- Characterized laser performance, including threshold current, wavelength, and thermal resistance.
Main Results:
- Demonstrated green VCSELs with wavelengths spanning 491.8 to 565.7 nm.
- Achieved world-record lowest threshold current, longest wavelength, and room-temperature continuous-wave (CW) lasing for green VCSELs.
- Observed low thermal resistance (915 kW⁻¹) contributing to stable CW operation.
Conclusions:
- Nanoscale quantum dots are key to achieving low threshold currents in green VCSELs.
- Cavity length modulation effectively tunes the emission wavelength by influencing electron-photon interaction.
- These green VCSELs are promising for compact, energy-efficient full-color displays and projectors.