Semiconductor laser

Example for direct band gap semiconductors are

• GaAs

• Ge

• Si

• AlSb

Direct band semiconductors are used to make

• Diode

• Transisters

• LED, Laser diodes

• Integrated circuits

Active medium in semiconductor laser is

• CO₂

• P-N junction diode

• Helium

• Neon

Wavelength produced by smeiconductor laser is

• 5000 Angstrom

• 6000 Angstrom

• 8400 to 8600 Angstrom

• None

The wavelength of the emitted radiations depends upon the -----------------------in GaAs

• Refractive Index

• Band gap, concentration of donor and acceptor atoms

• Current

• Resistance

To start the stimulated emissions in direct bandgap semiconductors is required

• low current density

• large divergence

• coherence

• Large current density

Which of the following has low threshold current density?

• Homojunction laser

• CO₂ laser

• Heterojunction laser

• He-Ne laser

In GaAs semiconductor diode, the band gap of GaAs is 1.44eV. Calculate the wavelength.

• 8400 Angstroms

• 8000 Angstroms

• 8628 Angstroms

• 8200 Angstroms

--------- is an injection laser.

• He-Ne laser

• Semiconductor laser

• Molecular gas laser

• Solid state laser

Pumping technique employed in semiconductor laser is -----------

• Direct conversion

• Optical pumping

• Electrical discharge method

• Chemicla reaction