4-quadrant photodetector
![PD4Q 4-quadrant photodetector PD4Q 4-quadrant photodetector](https://assets.koheron.com/images/products/pd4q/PD4Q.jpg?01072024141256)
![PD4Q 4-quadrant photodetector PD4Q 4-quadrant photodetector](https://assets.koheron.com/images/products/pd4q/PD4Q.jpg?01072024141256)
![PD4Q 4-quadrant photodetector output power spectral density PD4Q 4-quadrant photodetector output power spectral density](https://assets.koheron.com/images/products/pd4q/PD4Q-100k_output-power-spectral-density.png?01072024141256)
![PD4Q 4-quadrant photodetector frequency response PD4Q 4-quadrant photodetector frequency response](https://assets.koheron.com/images/products/pd4q/PD4Q_frequency-response.png?01072024141256)
![PD4Q 4-quadrant photodetector noise equivalent power PD4Q 4-quadrant photodetector noise equivalent power](https://assets.koheron.com/images/products/pd4q/PD4Q_noise-equivalent-power.png?01072024141256)
![PD4Q 4-quadrant photodetector functional diagram PD4Q 4-quadrant photodetector functional diagram](https://assets.koheron.com/images/products/pd4q/PD4Q_functional-diagram.png?01072024141256)
![PD4Q 4-quadrant photodetector position noise PD4Q 4-quadrant photodetector position noise](https://assets.koheron.com/images/products/pd4q/PD4Q-100k_position-noise.png?01072024141256)
Koheron PD4Q is a 4-quadrant photodetector with 100 kV/A transimpedance gain and 250 kHz bandwidth. The PD4Q outputs three voltages: X = (A+D)-(B+C), Y = (A+B)-(C+D) and SUM = (A+B+C+D)/4. Thanks to its low noise and high dynamic range, the PD4Q can measure laser beam position with a resolution below 20 nm in a 10 kHz bandwidth.
Quantity | Price |
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Resources
Specifications
PD4Q-10k | PD4Q-100k | |
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Detector | ||
Wavelength range | 400 nm to 1050 nm | 400 nm to 1050 nm |
Active area per quadrant | 12.3 mm² | 12.3 mm² |
Photodiode peak responsivity(900 nm) | 0.64 A/W | 0.64 A/W |
Maximum photocurrent per quadrant | 1 mA | 100 µA |
Electronics | ||
3 dB bandwidth | 500 kHz | 250 kHz |
Transimpedance gain | 10 kV/A | 100 kV/A |
Noise Equivalent Power(at 10 kHz) | 8.3 pW/√Hz | 1.6 pW/√Hz |
Output impedance | 1 kΩ | 1 kΩ |
Output voltage range | -10 V to 10 V | -10 V to 10 V |
Output | SMA female connector | SMA female connector |
Power supplies | ||
Positive supply voltage | 11.5 V to 13 V, nom. 12 V | 11.5 V to 13 V, nom. 12 V |
Negative supply voltage | -13 V to -11.5 V, nom. -12 V | -13 V to -11.5 V, nom. -12 V |
Quiescent current per rail | 20 mA | 20 mA |
Maximum current per rail | 75 mA | 75 mA |
Other | ||
Outside dimensions | 60 mm x 49 mm x 18 mm | 60 mm x 49 mm x 18 mm |
Operating temperature | 0 °C to 50 °C | 0 °C to 50 °C |
Weight | 43 g | 43 g |
More Photodetectors
Functional diagram
![PD4Q 4-quadrant photodetector functional diagram PD4Q 4-quadrant photodetector functional diagram](https://assets.koheron.com/images/products/pd4q/PD4Q_functional-diagram.png?01072024141256)
Characterization
Output noise
The figure below shows the X output (X = (A+D)-(B+C)) power spectral density, with and without light. The optical source is a 810 nm LED driven by a Koheron DRV110-A-375 laser driver.
Frequency response
The figure below shows the frequency response of the PD4Q photodetector.
![PD4Q 4-quadrant photodetector frequency response PD4Q 4-quadrant photodetector frequency response](https://assets.koheron.com/images/products/pd4q/PD4Q_frequency-response.png?01072024141256)
Noise Equivalent Power
The figure below shows the Noise Equivalent Power of the PD4Q photodetector measured at 810 nm.
![PD4Q 4-quadrant photodetector noise equivalent power PD4Q 4-quadrant photodetector noise equivalent power](https://assets.koheron.com/images/products/pd4q/PD4Q_noise-equivalent-power.png?01072024141256)
Position noise
The Noise Equivalent Power (NEP) of the detector can be converted into a position noise spectral density:
where $D$ is the beam diameter, $P_{\rm opt}$ is the total input optical power and $S$ is the photodiode responsivity. Below is the position noise over a $\Delta f$ = 10 kHz bandwidth for a 800 nm laser with 4 mm beam diameter:
![PD4Q-100k 4-quadrant photodetector position noise PD4Q-100k 4-quadrant photodetector position noise](https://assets.koheron.com/images/products/pd4q/PD4Q-100k_position-noise.png?01072024141256)