A laser diode, also known as an injection laser or diode laser, is a
semiconductor device
that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it.
What is principle of semiconductor laser?
When a p-n junction diode is forward biased,
the electrons from n – region and the holes from the p- region cross the junction and recombine with each other
. During the recombination process, the light radiation (photons) is released from a certain specified direct band gap semiconductors like Ga-As.
What is an example of a semiconductor laser?
One example of semiconductor laser is
diode laser
, which is currently the most efficient device for converting electrical energy into optical energy. It is a distant cousin of the light-emitting diode (LED) in that it is a semiconductor diode, which emits light.
What is made of semiconductor laser?
Compared to other laser types, semiconductor lasers are compact, reliable and last a long time. Such lasers consist of two basic components, an optical amplifier and a resonator. The amplifier is made from a
direct-bandgap semiconductor material based on either gallium arsenide (GaAs) or InP substrates
.
Where is semiconductor laser used?
Such characteristics make semiconductor lasers the most important type of lasers, technologically speaking. Their applications are extremely widespread and include
optical telecommunications, optical data storage, metrology, spectroscopy, material processing, pumping of other lasers, and medical treatments
.
What are the advantages of semiconductor laser?
The advantages of semiconductor lasers are:
small volume, lightweight, good reliability, long service life, and low power consumption
. In addition, semiconductor laser adopted low voltage constant current power supply mode, hence provided low powder failure rate, safe operation, and low cost of maintenance.
What are the application of laser?
- Laser cutting.
- Laser welding.
- Laser drilling.
- Laser marking.
- Laser cleaning.
- Laser cladding, a surface engineering process applied to mechanical components for reconditioning, repair work or hardfacing.
- Photolithography.
What are 3 types of lasers?
Types of lasers –
Solid state laser, Gas laser, Liquid laser & Semiconductor laser
.
What is laser principle?
The principle of laser amplification is
stimulated emission
. … As high laser powers saturate the gain by extracting energy from the gain medium, the laser power will in the steady state reach a level so that the saturated gain just equals the resonator losses (→ gain clamping).
What are the characteristics of semiconductor laser?
Semiconductor Laser is used for a variety of applications by taking advantage of characteristics that include
straightness, small emission spot size (several um), monochromaticity, high light density, and coherence
.
Which is the most efficient laser?
- The lowest lasing thresholds and the highest quality factors reported to date.
- Near 100% quantum yield (ratio of the number of photons emitted to those absorbed)
- Broad tunability of emissions covering the near infrared to visible wavelength region.
Which laser is eye safe?
Lasers with emission wavelengths longer than ≈ 1.4 μm
are often called “eye-safe”, because light in that wavelength range is strongly absorbed in the eye’s cornea and lens and therefore cannot reach the significantly more sensitive retina.
Are LEDs lasers?
The main difference between lasers and LEDs is that
a laser has one single wavelength
and a LED emits a Gaussian-like distribution of wavelengths as displayed in figure 1.
What are the types of semiconductor?
| Intrinsic Semiconductor Extrinsic Semiconductor | Pure semiconductor Impure semiconductor | Density of electrons is equal to the density of holes Density of electrons is not equal to the density of holes | Electrical conductivity is low Electrical conductivity is high |
|---|
Which is a semiconductor?
Semiconductors. Semiconductors are materials which have a conductivity between conductors (generally metals) and nonconductors or insulators (such as most ceramics). Semiconductors can be pure elements, such as
silicon
or germanium, or compounds such as gallium arsenide or cadmium selenide.
What is the importance of metastable state in a laser?
In a three-level laser, the material is first excited to a short-lived high-energy state that spontaneously drops to a somewhat lower-energy state with an unusually long lifetime, called a metastable state. The metastable state is important
because it traps and holds the excitation energy, building up a
…
