Properties of Photodetector
There are several properties of photodetector describes as follow:
- Responsivity
- Quantum Efficiency
- Dark Current
- Spectrum Response
- Response Time
- Gain
- Noise Equivalent Power
- Frequency Bandwidth
- Detectivity
Responsivity
It is defined as the power output divided by the total incident power input.
[Tex] \frac{v}{P \times A} in {\frac{V}{W}} [/Tex]
where
V =output voltage signal
P= radiation power
A= area of detector surface.
Quantum Efficiency
It is defined as the ratio of the number of charge carriers that are generated to the number of each photon.
[Tex]Quantum efficiency,\eta=\frac{no of charge camers generated}{no of absorbed incident photons} [/Tex]
There are two type of quantum efficiency: Internal quantum efficiency and external quantum efficiency.
- Internal quantum efficiency: It is the number of charge carriers generated over number of incidence photons.
- External quantum efficiency: It is the number of carriers crossing the electrode over the number of incidence photons.
Dark Current
It is defined as a photocurrent that flows even in the absence of the incident light.
Spectrum Response
It is defined as the range of spectrum over which the photodetector is over specified.
Response time
It is defined as the speed or response of the photodetector in the form of a function of the frequency of photon pulses.
Gain
It is defined as the ratio of output photocurrent to the total input current produced by the charge carriers. Gain,G should always be greater than 1.
G>1
Noise Equivalent Power
It is defined as the noise photocurrent divided by the peak radiant sensitivity.
Frequency Bandwidth
It is defined as the modulation frequency when the responsivity reduces by 3dB.
Detectivity
It is defined as the inverse of noise equivalent power.
[Tex]D=\frac{f \times a}{p} in \frac{cm \times HZ}{W} [/Tex]
where
P = noise power
f= frequency bandwidth.
Photodetector
A photo is nothing but light. A detector is nothing but a device that detects something. Therefore, we can directly conclude that a photodetector can be defined as a device that is used to detect light radiations by absorption. In this Article, We will be going through Photodetector, We will start our Article with What is Photodetector?, Then we will go through its brief Working, then we will go through its properties and go through all the types, At last, we will conclude our Article with Advantages, Disadvantages and Some FAQs.
Table of Content
- What is PhotoDetectors ?
- Working of PhotoDetector
- Classes of PhotoDetector
- Photodetector Properties
- Types of PhotoDetector
- Comparison Between Photodetector and Photodiode
- Applications of Photodetector