Intermediate high index layer for laser mode tuning in organic semiconductor lasers

Area of Science:

• Materials Science
• Optoelectronics
• Laser Physics

Background:

• Organic semiconductor lasers offer tunable emission properties.
• Distributed feedback (DFB) lasers rely on refractive index modulation for wavelength selection.
• Controlling the optical properties of the guided mode is crucial for tuning laser output.

Purpose of the Study:

• To modify the optical properties of organic semiconductor DFB lasers.
• To introduce a high refractive index intermediate layer to tune laser emission.
• To investigate the effect of intermediate layer thickness on laser mode and wavelength.

Main Methods:

• Fabrication of DFB lasers with a tantalum pentoxide (high refractive index) intermediate layer.
• Utilizing tris-(8-hydroxyquinoline) aluminium doped with a specific laser dye as the active layer.
• Varying the thickness of the tantalum pentoxide layer to alter the effective refractive index of the guided mode.

Main Results:

• Successful tuning of laser emission wavelength between 613 nm and 667 nm.
• Demonstrated control over the effective refractive index of the guided laser mode by adjusting intermediate layer thickness.
• Observed a shift in laser operation mode from TE(0) to TE(1) for tantalum pentoxide layer thicknesses exceeding 40 nm.

Conclusions:

• Introducing a high refractive index layer is an effective method for tuning the emission wavelength of organic semiconductor DFB lasers.
• The thickness of the intermediate layer plays a critical role in determining the laser's effective refractive index and operating mode.
• This technique provides a pathway for developing tunable organic laser sources.