Diode lasers, also known as semiconductor lasers, operate by passing an electric current through a semiconductor material. This process generates light, which is then amplified to produce a coherent laser beam. The specific wavelength of the laser depends on the band gap of the semiconductor material used.
In diode lasers, electrons and holes (positive electron vacancies) recombine in the semiconductor, releasing energy in the form of photons. The wavelength of these photons corresponds to the energy difference between the electron’s original and final energy states. This process is known as spontaneous emission.
The key components of a tunable diode laser include:
Semiconductor Material: The type of semiconductor (e.g., Gallium Arsenide, Indium Phosphide) largely determines the laser’s operational wavelength.
Laser Cavity: This is where light amplification occurs.
Waveguides: These guide the light through the laser, typically made from layers of different semiconductor materials, which confine the light path due to differences in refractive index.
Tuning Mechanism: This can be an external cavity with a movable reflector or a diffraction grating, a distributed feedback structure, or other methods to enable wavelength tuning.
Tunable diode lasers come in various forms, each with unique characteristics and mechanisms for tuning the wavelength. The two most common types are External Cavity Diode Lasers (ECDLs) and Distributed Feedback (DFB) lasers.
External Cavity Diode Lasers (ECDLs): ECDLs use a diode laser with an external optical cavity for wavelength selection. The cavity typically consists of a diffraction grating or a tunable filter. By adjusting the external cavity, the wavelength of the laser can be precisely controlled.
Distributed Feedback (DFB) Lasers: In DFB lasers, the wavelength tuning is achieved through the integration of a grating structure within the diode’s active region. The grating provides feedback at a specific wavelength, which can be slightly adjusted by changing the diode’s temperature or current.
MOK Optics produce various of lenses, laser mirrors, laser optics for Tunable diode lasers. If you need laser optics for tunable diode lasers, welcome to contact us.